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  • Community Conversation

    - by ultan o'broin
    Applications User Experience members (Erika Webb, Laurie Pattison, and I) attended the User Assistance Europe Conference in Stockholm, Sweden. We were impressed with the thought leadership and practical application of ideas in Anne Gentle's keynote address "Social Web Strategies for Documentation". After the conference, we spoke with Anne to explore the ideas further. Applications User Experience Senior Director Laurie Pattison (left) with Anne Gentle at the User Assistance Europe Conference In Anne's book called Conversation and Community: The Social Web for Documentation, she explains how user assistance is undergoing a seismic shift. The direction is away from the old print manuals and online help concept towards a web-based, user community-driven solution using social media tools. User experience professionals now have a vast range of such tools to start and nurture this "conversation": blogs, wikis, forums, social networking sites, microblogging systems, image and video sharing sites, virtual worlds, podcasts, instant messaging, mashups, and so on. That user communities are a rich source of user assistance is not a surprise, but the extent of available assistance is. For example, we know from the Consortium for Service Innovation that there has been an 'explosion' of user-generated content on the web. User-initiated community conversations provide as much as 30 times the number of official help desk solutions for consortium members! The growing reliance on user community solutions is clearly a user experience issue. Anne says that user assistance as conversation "means getting closer to users and helping them perform well. User-centered design has been touted as one of the most important ideas developed in the last 20 years of workplace writing. Now writers can take the idea of user-centered design a step further by starting conversations with users and enabling user assistance in interactions." Some of Anne's favorite examples of this paradigm shift from the world of traditional documentation to community conversation include: * Writer Bob Bringhurst's blog about Adobe InDesign and InCopy products and Adobe's community help * The Microsoft Development Network Community Center * ·The former Sun (now Oracle) OpenDS wiki, NetBeans Ruby and other community approaches to engage diverse audiences using screencasts, wikis, and blogs. * Cisco's customer support wiki, EMC's community, as well as Symantec and Intuit's approaches * The efforts of Ubuntu, Mozilla, and the FLOSS community generally Adobe Writer Bob Bringhurst's Blog Oracle is not without a user community conversation too. Besides the community discussions and blogs around documentation offerings, we have the My Oracle Support Community forums, Oracle Technology Network (OTN) communities, wiki, blogs, and so on. We have the great work done by our user groups and customer councils. Employees like David Haimes are reaching out, and enthusiastic non-employee gurus like Chet Justice (OracleNerd), Floyd Teter and Eddie Awad provide great "how-to" information too. But what does this paradigm shift mean for existing technical writers as users turn away from the traditional printable PDF manual deliverables? We asked Anne after the conference. The writer role becomes one of conversation initiator or enabler. The role evolves, along with the process, as the users define their concept of user assistance and terms of engagement with the product instead of having it pre-determined. It is largely a case now of "inventing the job while you're doing it, instead of being hired for it" Anne said. There is less emphasis on formal titles. Anne mentions that her own title "Content Stacker" at OpenStack; others use titles such as "Content Curator" or "Community Lead". However, the role remains one essentially about communications, "but of a new type--interacting with users, moderating, curating content, instead of sitting down to write a manual from start to finish." Clearly then, this role is open to more than professional technical writers. Product managers who write blogs, developers who moderate forums, support professionals who update wikis, rock star programmers with a penchant for YouTube are ideal. Anyone with the product knowledge, empathy for the user, and flair for relationships on the social web can join in. Some even perform these roles already but do not realize it. Anne feels the technical communicator space will move from hiring new community conversation professionals (who are already active in the space through blogging, tweets, wikis, and so on) to retraining some existing writers over time. Our own research reveals that the established proponents of community user assistance even set employee performance objectives for internal content curators about the amount of community content delivered by people outside the organization! To take advantage of the conversations on the web as user assistance, enterprises must first establish where on the spectrum their community lies. "What is the line between community willingness to contribute and the enterprise objectives?" Anne asked. "The relationship with users must be managed and also measured." Anne believes that the process can start with a "just do it" approach. Begin by reaching out to existing user groups, individual bloggers and tweeters, forum posters, early adopter program participants, conference attendees, customer advisory board members, and so on. Use analytical tools to measure the level of conversation about your products and services to show a return on investment (ROI), winning management support. Anne emphasized that success with the community model is dependent on lowering the technical and motivational barriers so that users can readily contribute to the conversation. Simple tools must be provided, and guidelines, if any, must be straightforward but not mandatory. The conversational approach is one where traditional style and branding guides do not necessarily apply. Tools and infrastructure help users to create content easily, to search and find the information online, read it, rate it, translate it, and participate further in the content's evolution. Recognizing contributors by using ratings on forums, giving out Twitter kudos, conference invitations, visits to headquarters, free products, preview releases, and so on, also encourages the adoption of the conversation model. The move to conversation as user assistance is not free, but there is a business ROI. The conversational model means that customer service is enhanced, as user experience moves from a functional to a valued, emotional level. Studies show a positive correlation between loyalty and financial performance (Consortium for Service Innovation, 2010), and as customer experience and loyalty become key differentiators, user experience professionals cannot explore the model's possibilities. The digital universe (measured at 1.2 million petabytes in 2010) is doubling every 12 to 18 months, and 70 percent of that universe consists of user-generated content (IDC, 2010). Conversation as user assistance cannot be ignored but must be embraced. It is a time to manage for abundance, not scarcity. Besides, the conversation approach certainly sounds more interesting, rewarding, and fun than the traditional model! I would like to thank Anne for her time and thoughts, and recommend that all user assistance professionals read her book. You can follow Anne on Twitter at: http://www.twitter.com/annegentle. Oracle's Acrolinx IQ deployment was used to author this article.

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  • LLBLGen Pro v3.1 released!

    - by FransBouma
    Yesterday we released LLBLGen Pro v3.1! Version 3.1 comes with new features and enhancements, which I'll describe briefly below. v3.1 is a free upgrade for v3.x licensees. What's new / changed? Designer Extensible Import system. An extensible import system has been added to the designer to import project data from external sources. Importers are plug-ins which import project meta-data (like entity definitions, mappings and relational model data) from an external source into the loaded project. In v3.1, an importer plug-in for importing project elements from existing LLBLGen Pro v3.x project files has been included. You can use this importer to create source projects from which you import parts of models to build your actual project with. Model-only relationships. In v3.1, relationships of the type 1:1, m:1 and 1:n can be marked as model-only. A model-only relationship isn't required to have a backing foreign key constraint in the relational model data. They're ideal for projects which have to work with relational databases where changes can't always be made or some relationships can't be added to (e.g. the ones which are important for the entity model, but are not allowed to be added to the relational model for some reason). Custom field ordering. Although fields in an entity definition don't really have an ordering, it can be important for some situations to have the entity fields in a given order, e.g. when you use compound primary keys. Field ordering can be defined using a pop-up dialog which can be opened through various ways, e.g. inside the project explorer, model view and entity editor. It can also be set automatically during refreshes based on new settings. Command line relational model data refresher tool, CliRefresher.exe. The command line refresh tool shipped with v2.6 is now available for v3.1 as well Navigation enhancements in various designer elements. It's now easier to find elements like entities, typed views etc. in the project explorer from editors, to navigate to related entities in the project explorer by right clicking a relationship, navigate to the super-type in the project explorer when right-clicking an entity and navigate to the sub-type in the project explorer when right-clicking a sub-type node in the project explorer. Minor visual enhancements / tweaks LLBLGen Pro Runtime Framework Entity creation is now up to 30% faster and takes 5% less memory. Creating an entity object has been optimized further by tweaks inside the framework to make instantiating an entity object up to 30% faster. It now also takes up to 5% less memory than in v3.0 Prefetch Path node merging is now up to 20-25% faster. Setting entity references required the creation of a new relationship object. As this relationship object is always used internally it could be cached (as it's used for syncing only). This increases performance by 20-25% in the merging functionality. Entity fetches are now up to 20% faster. A large number of tweaks have been applied to make entity fetches up to 20% faster than in v3.0. Full WCF RIA support. It's now possible to use your LLBLGen Pro runtime framework powered domain layer in a WCF RIA application using the VS.NET tools for WCF RIA services. WCF RIA services is a Microsoft technology for .NET 4 and typically used within silverlight applications. SQL Server DQE compatibility level is now per instance. (Usable in Adapter). It's now possible to set the compatibility level of the SQL Server Dynamic Query Engine (DQE) per instance of the DQE instead of the global setting it was before. The global setting is still available and is used as the default value for the compatibility level per-instance. You can use this to switch between CE Desktop and normal SQL Server compatibility per DataAccessAdapter instance. Support for COUNT_BIG aggregate function (SQL Server specific). The aggregate function COUNT_BIG has been added to the list of available aggregate functions to be used in the framework. Minor changes / tweaks I'm especially pleased with the import system, as that makes working with entity models a lot easier. The import system lets you import from another LLBLGen Pro v3 project any entity definition, mapping and / or meta-data like table definitions. This way you can build repository projects where you store model fragments, e.g. the building blocks for a customer-order system, a user credential model etc., any model you can think of. In most projects, you'll recognize that some parts of your new model look familiar. In these cases it would have been easier if you would have been able to import these parts from projects you had pre-created. With LLBLGen Pro v3.1 you can. For example, say you have an Oracle schema called CRM which contains the bread 'n' butter customer-order-product kind of model. You create an entity model from that schema and save it in a project file. Now you start working on another project for another customer and you have to use SQL Server. You also start using model-first development, so develop the entity model from scratch as there's no existing database. As this customer also requires some CRM like entity model, you import the entities from your saved Oracle project into this new SQL Server targeting project. Because you don't work with Oracle this time, you don't import the relational meta-data, just the entities, their relationships and possibly their inheritance hierarchies, if any. As they're now entities in your project you can change them a bit to match the new customer's requirements. This can save you a lot of time, because you can re-use pre-fab model fragments for new projects. In the example above there are no tables yet (as you work model first) so using the forward mapping capabilities of LLBLGen Pro v3 creates the tables, PK constraints, Unique Constraints and FK constraints for you. This way you can build a nice repository of model fragments which you can re-use in new projects.

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  • Life Technologies: Making Life Easier to Manage

    - by Michael Snow
    12.00 Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-family:"Calibri","sans-serif"; mso-bidi-font-family:"Times New Roman";} When we’re thinking about customer engagement, we’re acutely aware of all the forces at play competing for our customer’s attention. Solutions that make life easier for our customers draw attention to themselves. We tend to engage more when there is a distinct benefit and we can take a deep breath and accept that there is hope in the world and everything isn’t designed to frustrate us and make our lives miserable. (sigh…) When products are designed to automate processes that were consuming hours of our time with no relief in sight, they deserve to be recognized. One of our recent Oracle Fusion Middleware Innovation Award Winners in the WebCenter category, Life Technologies, has recently posted a video promoting their “award winning” solution. The Oracle Innovation Awards are part of the overall Oracle Excellence awards given to customers for innovation with Oracle products. More info here. Their award nomination included this description: Life Technologies delivered the My Life Service Portal as part of a larger Digital Hub strategy. This Portal is the first of its kind in the biotechnology service providing industry. The Portal provides access to Life Technologies cloud based service monitoring system where all customer deployed instruments can be remotely monitored and proactively repaired. The portal provides alerts from these cloud based monitoring services directly to the customer and to Life Technologies Field Engineers. The Portal provides insight into the instruments and services customers purchased for the purpose of analyzing and anticipating future customer needs and creating targeted sales and service programs. This portal not only provides benefits for Life Technologies internal sales and service teams but provides customers a central place to track all pertinent instrument information including: instrument service history instrument status and previous activities instrument performance analytics planned service visits warranty/contract information discussion forums social networks for lab management and collaboration alerts and notifications on all of the above team scheduling for instrument usage promote optional reagents required to keep instruments performing From their website The Life Technologies Instruments & Services Portal Helps You Save Time and Gain Peace of Mind Introducing the new, award-winning, free online tool that enables easier management of your instrument use and care, faster response to requests for service or service quotes, and instant sharing of key instrument and service information with your colleagues. Now – this unto itself is obviously beneficial for their customers who were previously burdened with having to do all of these tasks separately, manually and inconsistently by nature. Now – all in one place and free to their customers – a portal that ties it all together. They now have built the platform to give their customers yet another reason to do business with them – Their headline on their product page says it all: “Life is now easier to manage - All your instrument use and care in one place – the no-cost, no-hassle Instruments and Services Portal.” Of course – it’s very convenient that the company name includes “Life” and now can also promote to their clients and prospects that doing business with them is easy and their sophisticated lab equipment is easy to manage. In an industry full of PhD’s – “Easy” isn’t usually the first word that comes to mind, but Life Technologies has now tied the word to their brand in a very eloquent way. Between our work lives and family or personal lives, getting any mono-focused minutes of dedicated attention has become such a rare occurrence in our current era of multi-tasking that those moments of focus are highly prized. So – when something is done really well – so well that it becomes captivating and urges sharing impulses – I take notice and dig deeper and most of the time I discover other gems not so hidden below the surface. And then I share with those I know would enjoy and understand. In the spirit of full disclosure, I must admit here that the first person I shared the videos below with was my daughter. She’s in her senior year of high school in the midst of her college search. She’s passionate about her academics and has already decided that she wants to study Neuroscience in college and like her mother will be in for the long haul to a PhD eventually. In a summer science program at Smith College 2 summers ago – she sent the family famous text to me – “I just dissected a sheep’s brain – wicked cool!” – This was followed by an equally memorable text this past summer in a research mentorship in Neuroscience at UConn – “Just sliced up some rat brain. Reminded me of a deli slicer at the supermarket… sorry I forgot to call last night…” So… needless to say – I knew I had an audience that would enjoy and understand these videos below and are now being shared among her science classmates and faculty. And evidently - so does Life Technologies! They’ve done a great job on these making them fun and something that will easily be shared among their customers social networks. They’ve created a neuro-archetypal character, “Ph.Diddy” and know that their world of clients in academics, research, and other institutions would understand and enjoy the “edutainment” value in this series of videos on their YouTube channel that pokes fun at the stereotypes while also promoting their products at the same time. They use their Facebook page for additional engagement with their clients and as another venue to promote these videos. Enjoy this one as well! More to be found here: http://www.youtube.com/lifetechnologies Stay tuned to this Oracle WebCenter blog channel. Tomorrow we'll be taking a look at another winner of the Innovation Awards, LADWP - helping to keep the citizens of Los Angeles engaged with their Water and Power provider.

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  • Five Ways Enterprise 2.0 Can Transform Your Business - Q&A from the Webcast

    - by [email protected]
    A few weeks ago, Vince Casarez and I presented with KMWorld on the Five Ways Enterprise 2.0 Can Transform Your Business. It was an enjoyable, interactive webcast in which Vince and I discussed the ways Enterprise 2.0 can transform your business and more importantly, highlighted key customer examples of how to do so. If you missed the webcast, you can catch a replay here. We had a lot of audience participation in some of the polls we conducted and in the Q&A session. We weren't able to address all of the questions during the broadcast, so we attempted to answer them here: Q: Which area within your firm focuses on Web 2.0? Meaning, do you find new departments developing just to manage the web 2.0 (Twitter, Facebook, etc.) user experience or are you structuring current departments? A: There are three distinct efforts within Oracle. The first is around delivery of these Web 2.0 services for enterprise deployments. This is the focus of the WebCenter team. The second effort is injecting these Web 2.0 services into use cases that drive the different enterprise applications. This effort is focused on how to manage these external services and bring them into a cohesive flow for marketing programs, customer care, and purchasing. The third effort is how we consume these services internally to enhance Oracle's business delivery. It leverages the technologies and use cases of the first two but also pushes the envelope with regards to future directions of these other two areas. Q: In a business, Web 2.0 is mostly like action logs. How can we leverage the official process practice versus the logs of a recent action? Example: a system configuration modified last night on a call out versus the official practice that everybody would use in the morning.A: The key thing to remember is that most Web 2.0 actions / activity streams today are based on collaboration and communication type actions. At least with public social sites like Facebook and Twitter. What we're delivering as part of the WebCenter Suite are not just these types of activities but also enterprise application activities. These enterprise application activities come from different application modules: purchasing, HR, order entry, sales opportunity, etc. The actions within these systems are normally tied to a business object or process: purchase order/customer, employee or department, customer and supplier, customer and product, respectively. Therefore, the activities or "logs" as you name them are able to be "typed" so that as a viewer, you can filter or decide to see only certain types of information. In your example, you could have a view that only showed you recent "configuration" changes and this could be right next to a view that showed off the items to be watched every morning. Q: It's great to hear about customers using the software but is there any plan for future webinars to show what the products/installs look like? That would be very helpful.A: We don't have a webinar planned to show off the install process. However, we have a viewlet that's posted on Oracle Technology Network. You can see it here:http://www.oracle.com/technetwork/testcontent/wcs-install-098014.htmlAnd we've got excellent documentation that walks you through the steps here:http://download.oracle.com/docs/cd/E14571_01/install.1111/e12001/install.htmAnd there's a whole set of demos and examples of what WebCenter can do at this URL:http://www.oracle.com/technetwork/middleware/webcenter/release11-demos-097468.html Q: How do you anticipate managing metadata across the enterprise to make content findable?A: We need to first make sure we are all talking about the same thing when we use a word like "metadata". Here's why...  For a developer, metadata means information that describes key elements of the portal or application and what the portal or application can do. For content systems, metadata means key terms that provide a taxonomy or folksonomy about the information that is being indexed, ordered, and managed. For business intelligence systems, metadata means key terms that provide labels to groups of data that most non-mathematicians need to understand. And for SOA, metadata means labels for parts of the processes that business owners should understand that connect development terminology. There are also additional requirements for metadata to be available to the team building these new solutions as well as requirements to make this metadata available to the running system. These requirements are often separated by "design time" and "run time" respectively. So clearly, a general goal of managing metadata across the enterprise is very challenging. We've invested a huge amount of resources around Oracle Metadata Services (MDS) to be able to provide a more generic system for all of these elements. No other vendor has anything like this technology foundation in their products. This provides a huge benefit to our customers as they will now be able to find content, processes, people, and information from a common set of search interfaces with consistent enterprise wide results. Q: Can you give your definition of terms as to document and content, please?A: Content applies to a broad category of information from Word documents, presentations and reports through attachments to invoices and/or purchase orders. Content is essentially any type of digital asset including images, video, and voice. A document is just one type of content. Q: Do you have special integration tools to realize an interaction between UCM and WebCenter Spaces/Services?A: Yes, we've dedicated a whole team of engineers to exploit the key features of Oracle UCM within WebCenter.  While ensuring that WebCenter can connect to other non-Oracle systems, we've made sure that with the combined set of Oracle technology, no other solution can match the combined power and integration.  This is part of the Oracle Fusion Middleware strategy which is to provide best in class capabilities for Content and Portals.  When combined together, the synergy between the two products enables users to quickly add capabilities when they are needed.  For example, simple document sharing is part of the combined product offering, but if legal discovery or archiving is required, Oracle UCM product includes these capabilities that can be quickly added.  There's no need to move content around or add another system to support this, it's just a feature that gets turned on within Oracle UCM. Q: All customers have some interaction with their applications and have many older versions, how do you see some of these new Enterprise 2.0 capabilities adding value to existing enterprise application deployments?A: Just as Service Oriented Architectures allowed for connecting the processes of different applications systems to work together, there's a need for a similar approach with regards to these enterprise 2.0 capabilities. Oracle WebCenter is built on a core architecture that allows for SOA of these Enterprise 2.0 services so that one set of scalable services can be used and integrated directly into any type of application. In this way, users can get immediate value out of the Enterprise 2.0 capabilities without having to wait for the next major release or upgrade. These centrally managed WebCenter services expose a set of standard interfaces that make it extremely easy to add them into existing applications no matter what technology the application has been implemented. Q: We've heard about Oracle Next Generation applications called "Fusion Applications", can you tell me how all this works together?A: Oracle WebCenter powers the core collaboration and social computing services found within Fusion Applications. It is the core user experience technology for how all the application screens have been implemented. And the core concept of task flows allows for all the Fusion Applications modules to be adaptable and composable by business users and IT without needing to be a professional developer. Oracle WebCenter is at the heart of the new Fusion Applications. In addition, the same patterns and technologies are now being added to the existing applications including JD Edwards, Siebel, Peoplesoft, and eBusiness Suite. The core technology enables all these customers to have a much smoother upgrade path to Fusion Applications. They get immediate benefits of injecting new user interactions into their existing applications without having to completely move to Fusion Applications. And then when the time comes, their users will already be well versed in how the new capabilities work. Q: Does any of this work with non Oracle software? Other databases? Other application servers? etc.A: We have made sure that Oracle WebCenter delivers the broadest set of development choices so that no matter what technology you developers are using, WebCenter capabilities can be quickly and easily added to the site or application. In addition, we have certified Oracle WebCenter to run against non-Oracle databases like DB2 and SQLServer. We have stated plans for certification against MySQL as well. Later in CY 2011, Oracle will provide certification on non-Oracle application servers such as WebSphere and JBoss. Q: How do we balance User and IT requirements in regards to Enterprise 2.0 technologies?A: Wrong decisions are often made because employee knowledge is not tapped efficiently and opportunities to innovate are often missed because the right people do not work together. Collaboration amongst workers in the right business context is critical for success. While standalone Enterprise 2.0 technologies can improve collaboration for collaboration's sake, using social collaboration tools in the context of business applications and processes will improve business responsiveness and lead companies to a more competitive position. As these systems become more mission critical it is essential that they maintain the highest level of performance and availability while scaling to support larger communities. Q: What are the ways in which Enterprise 2.0 can improve business responsiveness?A: With a wide range of Enterprise 2.0 tools in the marketplace, CIOs need to deploy solutions that will meet the requirements from users as well as address the requirements from IT. Workers want a next-generation user experience that is personalized and aggregates their daily tools and tasks, while IT needs to ensure the solution is secure, scalable, flexible, reliable and easily integrated with existing systems. An open and integrated approach to deploying portals, content management, and collaboration can enhance your business by addressing both the needs of knowledge workers for better information and the IT mandate to conserve resources by simplifying, consolidating and centralizing infrastructure and administration.  

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  • DRY and SRP

    - by Timothy Klenke
    Originally posted on: http://geekswithblogs.net/TimothyK/archive/2014/06/11/dry-and-srp.aspxKent Beck’s XP Simplicity Rules (aka Four Rules of Simple Design) are a prioritized list of rules that when applied to your code generally yield a great design.  As you’ll see from the above link the list has slightly evolved over time.  I find today they are usually listed as: All Tests Pass Don’t Repeat Yourself (DRY) Express Intent Minimalistic These are prioritized.  If your code doesn’t work (rule 1) then everything else is forfeit.  Go back to rule one and get the code working before worrying about anything else. Over the years the community have debated whether the priority of rules 2 and 3 should be reversed.  Some say a little duplication in the code is OK as long as it helps express intent.  I’ve debated it myself.  This recent post got me thinking about this again, hence this post.   I don’t think it is fair to compare “Expressing Intent” against “DRY”.  This is a comparison of apples to oranges.  “Expressing Intent” is a principal of code quality.  “Repeating Yourself” is a code smell.  A code smell is merely an indicator that there might be something wrong with the code.  It takes further investigation to determine if a violation of an underlying principal of code quality has actually occurred. For example “using nouns for method names”, “using verbs for property names”, or “using Booleans for parameters” are all code smells that indicate that code probably isn’t doing a good job at expressing intent.  They are usually very good indicators.  But what principle is the code smell of Duplication pointing to and how good of an indicator is it? Duplication in the code base is bad for a couple reasons.  If you need to make a change and that needs to be made in a number of locations it is difficult to know if you have caught all of them.  This can lead to bugs if/when one of those locations is overlooked.  By refactoring the code to remove all duplication there will be left with only one place to change, thereby eliminating this problem. With most projects the code becomes the single source of truth for a project.  If a production code base is inconsistent with a five year old requirements or design document the production code that people are currently living with is usually declared as the current reality (or truth).  Requirement or design documents at this age in a project life cycle are usually of little value. Although comparing production code to external documentation is usually straight forward, duplication within the code base muddles this declaration of truth.  When code is duplicated small discrepancies will creep in between the two copies over time.  The question then becomes which copy is correct?  As different factions debate how the software should work, trust in the software and the team behind it erodes. The code smell of Duplication points to a violation of the “Single Source of Truth” principle.  Let me define that as: A stakeholder’s requirement for a software change should never cause more than one class to change. Violation of the Single Source of Truth principle will always result in duplication in the code.  However, the inverse is not always true.  Duplication in the code does not necessarily indicate that there is a violation of the Single Source of Truth principle. To illustrate this, let’s look at a retail system where the system will (1) send a transaction to a bank and (2) print a receipt for the customer.  Although these are two separate features of the system, they are closely related.  The reason for printing the receipt is usually to provide an audit trail back to the bank transaction.  Both features use the same data:  amount charged, account number, transaction date, customer name, retail store name, and etcetera.  Because both features use much of the same data, there is likely to be a lot of duplication between them.  This duplication can be removed by making both features use the same data access layer. Then start coming the divergent requirements.  The receipt stakeholder wants a change so that the account number has the last few digits masked out to protect the customer’s privacy.  That can be solve with a small IF statement whilst still eliminating all duplication in the system.  Then the bank wants to take a picture of the customer as well as capture their signature and/or PIN number for enhanced security.  Then the receipt owner wants to pull data from a completely different system to report the customer’s loyalty program point total. After a while you realize that the two stakeholders have somewhat similar, but ultimately different responsibilities.  They have their own reasons for pulling the data access layer in different directions.  Then it dawns on you, the Single Responsibility Principle: There should never be more than one reason for a class to change. In this example we have two stakeholders giving two separate reasons for the data access class to change.  It is clear violation of the Single Responsibility Principle.  That’s a problem because it can often lead the project owner pitting the two stakeholders against each other in a vein attempt to get them to work out a mutual single source of truth.  But that doesn’t exist.  There are two completely valid truths that the developers need to support.  How is this to be supported and honour the Single Responsibility Principle?  The solution is to duplicate the data access layer and let each stakeholder control their own copy. The Single Source of Truth and Single Responsibility Principles are very closely related.  SST tells you when to remove duplication; SRP tells you when to introduce it.  They may seem to be fighting each other, but really they are not.  The key is to clearly identify the different responsibilities (or sources of truth) over a system.  Sometimes there is a single person with that responsibility, other times there are many.  This can be especially difficult if the same person has dual responsibilities.  They might not even realize they are wearing multiple hats. In my opinion Single Source of Truth should be listed as the second rule of simple design with Express Intent at number three.  Investigation of the DRY code smell should yield to the proper application SST, without violating SRP.  When necessary leave duplication in the system and let the class names express the different people that are responsible for controlling them.  Knowing all the people with responsibilities over a system is the higher priority because you’ll need to know this before you can express it.  Although it may be a code smell when there is duplication in the code, it does not necessarily mean that the coder has chosen to be expressive over DRY or that the code is bad.

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  • Mysql - help me optimize this query

    - by sandeepan-nath
    About the system: -The system has a total of 8 tables - Users - Tutor_Details (Tutors are a type of User,Tutor_Details table is linked to Users) - learning_packs, (stores packs created by tutors) - learning_packs_tag_relations, (holds tag relations meant for search) - tutors_tag_relations and tags and orders (containing purchase details of tutor's packs), order_details linked to orders and tutor_details. For a more clear idea about the tables involved please check the The tables section in the end. -A tags based search approach is being followed.Tag relations are created when new tutors register and when tutors create packs (this makes tutors and packs searcheable). For details please check the section How tags work in this system? below. Following is a simpler representation (not the actual) of the more complex query which I am trying to optimize:- I have used statements like explanation of parts in the query select SUM(DISTINCT( t.tag LIKE "%Dictatorship%" )) as key_1_total_matches, SUM(DISTINCT( t.tag LIKE "%democracy%" )) as key_2_total_matches, td., u., count(distinct(od.id_od)), if (lp.id_lp > 0) then some conditional logic on lp fields else 0 as tutor_popularity from Tutor_Details AS td JOIN Users as u on u.id_user = td.id_user LEFT JOIN Learning_Packs_Tag_Relations AS lptagrels ON td.id_tutor = lptagrels.id_tutor LEFT JOIN Learning_Packs AS lp ON lptagrels.id_lp = lp.id_lp LEFT JOIN `some other tables on lp.id_lp - let's call learning pack tables set (including Learning_Packs table)` LEFT JOIN Order_Details as od on td.id_tutor = od.id_author LEFT JOIN Orders as o on od.id_order = o.id_order LEFT JOIN Tutors_Tag_Relations as ttagrels ON td.id_tutor = ttagrels.id_tutor JOIN Tags as t on (t.id_tag = ttagrels.id_tag) OR (t.id_tag = lptagrels.id_tag) where some condition on Users table's fields AND CASE WHEN ((t.id_tag = lptagrels.id_tag) AND (lp.id_lp 0)) THEN `some conditions on learning pack tables set` ELSE 1 END AND CASE WHEN ((t.id_tag = wtagrels.id_tag) AND (wc.id_wc 0)) THEN `some conditions on webclasses tables set` ELSE 1 END AND CASE WHEN (od.id_od0) THEN od.id_author = td.id_tutor and some conditions on Orders table's fields ELSE 1 END AND ( t.tag LIKE "%Dictatorship%" OR t.tag LIKE "%democracy%") group by td.id_tutor HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 order by tutor_popularity desc, u.surname asc, u.name asc limit 0,20 ===================================================================== What does the above query do? Does AND logic search on the search keywords (2 in this example - "Democracy" and "Dictatorship"). Returns only those tutors for which both the keywords are present in the union of the two sets - tutors details and details of all the packs created by a tutor. To make things clear - Suppose a Tutor name "Sandeepan Nath" has created a pack "My first pack", then:- Searching "Sandeepan Nath" returns Sandeepan Nath. Searching "Sandeepan first" returns Sandeepan Nath. Searching "Sandeepan second" does not return Sandeepan Nath. ====================================================================================== The problem The results returned by the above query are correct (AND logic working as per expectation), but the time taken by the query on heavily loaded databases is like 25 seconds as against normal query timings of the order of 0.005 - 0.0002 seconds, which makes it totally unusable. It is possible that some of the delay is being caused because all the possible fields have not yet been indexed, but I would appreciate a better query as a solution, optimized as much as possible, displaying the same results ========================================================================================== How tags work in this system? When a tutor registers, tags are entered and tag relations are created with respect to tutor's details like name, surname etc. When a Tutors create packs, again tags are entered and tag relations are created with respect to pack's details like pack name, description etc. tag relations for tutors stored in tutors_tag_relations and those for packs stored in learning_packs_tag_relations. All individual tags are stored in tags table. ==================================================================== The tables Most of the following tables contain many other fields which I have omitted here. CREATE TABLE IF NOT EXISTS users ( id_user int(10) unsigned NOT NULL AUTO_INCREMENT, name varchar(100) NOT NULL DEFAULT '', surname varchar(155) NOT NULL DEFAULT '', PRIMARY KEY (id_user) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=636 ; CREATE TABLE IF NOT EXISTS tutor_details ( id_tutor int(10) NOT NULL AUTO_INCREMENT, id_user int(10) NOT NULL DEFAULT '0', PRIMARY KEY (id_tutor), KEY Users_FKIndex1 (id_user) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=51 ; CREATE TABLE IF NOT EXISTS orders ( id_order int(10) unsigned NOT NULL AUTO_INCREMENT, PRIMARY KEY (id_order), KEY Orders_FKIndex1 (id_user), ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=275 ; ALTER TABLE orders ADD CONSTRAINT Orders_ibfk_1 FOREIGN KEY (id_user) REFERENCES users (id_user) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS order_details ( id_od int(10) unsigned NOT NULL AUTO_INCREMENT, id_order int(10) unsigned NOT NULL DEFAULT '0', id_author int(10) NOT NULL DEFAULT '0', PRIMARY KEY (id_od), KEY Order_Details_FKIndex1 (id_order) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=284 ; ALTER TABLE order_details ADD CONSTRAINT Order_Details_ibfk_1 FOREIGN KEY (id_order) REFERENCES orders (id_order) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS learning_packs ( id_lp int(10) unsigned NOT NULL AUTO_INCREMENT, id_author int(10) unsigned NOT NULL DEFAULT '0', PRIMARY KEY (id_lp), KEY Learning_Packs_FKIndex2 (id_author), KEY id_lp (id_lp) ) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=23 ; CREATE TABLE IF NOT EXISTS tags ( id_tag int(10) unsigned NOT NULL AUTO_INCREMENT, tag varchar(255) DEFAULT NULL, PRIMARY KEY (id_tag), UNIQUE KEY tag (tag), KEY id_tag (id_tag), KEY tag_2 (tag), KEY tag_3 (tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=3419 ; CREATE TABLE IF NOT EXISTS tutors_tag_relations ( id_tag int(10) unsigned NOT NULL DEFAULT '0', id_tutor int(10) DEFAULT NULL, KEY Tutors_Tag_Relations (id_tag), KEY id_tutor (id_tutor), KEY id_tag (id_tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; ALTER TABLE tutors_tag_relations ADD CONSTRAINT Tutors_Tag_Relations_ibfk_1 FOREIGN KEY (id_tag) REFERENCES tags (id_tag) ON DELETE NO ACTION ON UPDATE NO ACTION; CREATE TABLE IF NOT EXISTS learning_packs_tag_relations ( id_tag int(10) unsigned NOT NULL DEFAULT '0', id_tutor int(10) DEFAULT NULL, id_lp int(10) unsigned DEFAULT NULL, KEY Learning_Packs_Tag_Relations_FKIndex1 (id_tag), KEY id_lp (id_lp), KEY id_tag (id_tag) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; ALTER TABLE learning_packs_tag_relations ADD CONSTRAINT Learning_Packs_Tag_Relations_ibfk_1 FOREIGN KEY (id_tag) REFERENCES tags (id_tag) ON DELETE NO ACTION ON UPDATE NO ACTION; =================================================================================== Following is the exact query (this includes classes also - tutors can create classes and search terms are matched with classes created by tutors):- select count(distinct(od.id_od)) as tutor_popularity, CASE WHEN (IF((wc.id_wc 0), ( wc.wc_api_status = 1 AND wc.wc_type = 0 AND wc.class_date '2010-06-01 22:00:56' AND wccp.status = 1 AND (wccp.country_code='IE' or wccp.country_code IN ('INT'))), 0)) THEN 1 ELSE 0 END as 'classes_published', CASE WHEN (IF((lp.id_lp 0), (lp.id_status = 1 AND lp.published = 1 AND lpcp.status = 1 AND (lpcp.country_code='IE' or lpcp.country_code IN ('INT'))),0)) THEN 1 ELSE 0 END as 'packs_published', td . * , u . * from Tutor_Details AS td JOIN Users as u on u.id_user = td.id_user LEFT JOIN Learning_Packs_Tag_Relations AS lptagrels ON td.id_tutor = lptagrels.id_tutor LEFT JOIN Learning_Packs AS lp ON lptagrels.id_lp = lp.id_lp LEFT JOIN Learning_Packs_Categories AS lpc ON lpc.id_lp_cat = lp.id_lp_cat LEFT JOIN Learning_Packs_Categories AS lpcp ON lpcp.id_lp_cat = lpc.id_parent LEFT JOIN Learning_Pack_Content as lpct on (lp.id_lp = lpct.id_lp) LEFT JOIN Webclasses_Tag_Relations AS wtagrels ON td.id_tutor = wtagrels.id_tutor LEFT JOIN WebClasses AS wc ON wtagrels.id_wc = wc.id_wc LEFT JOIN Learning_Packs_Categories AS wcc ON wcc.id_lp_cat = wc.id_wp_cat LEFT JOIN Learning_Packs_Categories AS wccp ON wccp.id_lp_cat = wcc.id_parent LEFT JOIN Order_Details as od on td.id_tutor = od.id_author LEFT JOIN Orders as o on od.id_order = o.id_order LEFT JOIN Tutors_Tag_Relations as ttagrels ON td.id_tutor = ttagrels.id_tutor JOIN Tags as t on (t.id_tag = ttagrels.id_tag) OR (t.id_tag = lptagrels.id_tag) OR (t.id_tag = wtagrels.id_tag) where (u.country='IE' or u.country IN ('INT')) AND CASE WHEN ((t.id_tag = lptagrels.id_tag) AND (lp.id_lp 0)) THEN lp.id_status = 1 AND lp.published = 1 AND lpcp.status = 1 AND (lpcp.country_code='IE' or lpcp.country_code IN ('INT')) ELSE 1 END AND CASE WHEN ((t.id_tag = wtagrels.id_tag) AND (wc.id_wc 0)) THEN wc.wc_api_status = 1 AND wc.wc_type = 0 AND wc.class_date '2010-06-01 22:00:56' AND wccp.status = 1 AND (wccp.country_code='IE' or wccp.country_code IN ('INT')) ELSE 1 END AND CASE WHEN (od.id_od0) THEN od.id_author = td.id_tutor and o.order_status = 'paid' and CASE WHEN (od.id_wc 0) THEN od.can_attend_class=1 ELSE 1 END ELSE 1 END AND 1 group by td.id_tutor order by tutor_popularity desc, u.surname asc, u.name asc limit 0,20 Please note - The provided database structure does not show all the fields and tables as in this query

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  • Can this Query be corrected or different table structure needed? (database dumps provided)

    - by sandeepan
    This is a bit lengthy but I have provided sufficient details and kept things very clear. Please see if you can help. (I will surely accept answer if it solves my problem) I am sure a person experienced with this can surely help or suggest me to decide the tables structure. About the system:- There are tutors who create classes A tags based search approach is being followed Tag relations are created/edited when new tutors registers/edits profile data and when tutors create classes (this makes tutors and classes searcheable).For simplicity, let us consider only tutor name and class name are the fields which are matched against search keywords. In this example, I am considering - tutor "Sandeepan Nath" has created a class called "first class" tutor "Bob Cratchit" has created a class called "new class" Desired search results- AND logic to be appied on the search keywords and match against class and tutor data(class name + tutor name), in other words, All those classes be shown such that all the search terms are present in the class name or its tutor name. Example to be clear - Searching "first class" returns class with id_wc = 1. Working Searching "Sandeepan class" should also return class with id_wc = 1. Not working in System 2. Problem with profile editing and searching To tell in one sentence, I am facing a conflict between the ease of profile edition (edition of tag relations when tutor profiles are edited) and the ease of search logic. In the beginning, we had one table structure and search was easy but tag edition logic was very clumsy and unmaintainable(Check System 1 in the section below) . So we created separate tag relations tables to make profile edition simpler but search has become difficult. Please dump the tables so that you can run the search query I have given below and see the results. System 1 (previous system - search easy - profile edition difficult):- Only one table called All_Tag_Relations table had the all the tag relations. The tags table below is common to both systems 1 and 2. CREATE TABLE IF NOT EXISTS `all_tag_relations` ( `id_tag_rel` int(10) NOT NULL AUTO_INCREMENT, `id_tag` int(10) unsigned NOT NULL DEFAULT '0', `id_tutor` int(10) DEFAULT NULL, `id_wc` int(10) unsigned DEFAULT NULL, PRIMARY KEY (`id_tag_rel`), KEY `All_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_wc` (`id_wc`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `all_tag_relations` (`id_tag_rel`, `id_tag`, `id_tutor`, `id_wc`) VALUES (1, 1, 1, NULL), (2, 2, 1, NULL), (3, 1, 1, 1), (4, 2, 1, 1), (5, 3, 1, 1), (6, 4, 1, 1), (7, 6, 2, NULL), (8, 7, 2, NULL), (9, 6, 2, 2), (10, 7, 2, 2), (11, 5, 2, 2), (12, 4, 2, 2); CREATE TABLE IF NOT EXISTS `tags` ( `id_tag` int(10) unsigned NOT NULL AUTO_INCREMENT, `tag` varchar(255) DEFAULT NULL, PRIMARY KEY (`id_tag`), UNIQUE KEY `tag` (`tag`), KEY `id_tag` (`id_tag`), KEY `tag_2` (`tag`), KEY `tag_3` (`tag`), KEY `tag_4` (`tag`), FULLTEXT KEY `tag_5` (`tag`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=8 ; INSERT INTO `tags` (`id_tag`, `tag`) VALUES (1, 'Sandeepan'), (2, 'Nath'), (3, 'first'), (4, 'class'), (5, 'new'), (6, 'Bob'), (7, 'Cratchit'); Please note that for every class, the tag rels of its tutor have to be duplicated. Example, for class with id_wc=1, the tag rel records with id_tag_rel = 3 and 4 are actually extras if you compare with the tag rel records with id_tag_rel = 1 and 2. System 2 (present system - profile edition easy, search difficult) Two separate tables Tutors_Tag_Relations and Webclasses_Tag_Relations have the corresponding tag relations data (Please dump into a separate database)- CREATE TABLE IF NOT EXISTS `tutors_tag_relations` ( `id_tag_rel` int(10) NOT NULL AUTO_INCREMENT, `id_tag` int(10) unsigned NOT NULL DEFAULT '0', `id_tutor` int(10) DEFAULT NULL, PRIMARY KEY (`id_tag_rel`), KEY `All_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `tutors_tag_relations` (`id_tag_rel`, `id_tag`, `id_tutor`) VALUES (1, 1, 1), (2, 2, 1), (3, 6, 2), (4, 7, 2); CREATE TABLE IF NOT EXISTS `webclasses_tag_relations` ( `id_tag_rel` int(10) NOT NULL AUTO_INCREMENT, `id_tag` int(10) unsigned NOT NULL DEFAULT '0', `id_tutor` int(10) DEFAULT NULL, `id_wc` int(10) DEFAULT NULL, PRIMARY KEY (`id_tag_rel`), KEY `webclasses_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_wc` (`id_wc`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `webclasses_tag_relations` (`id_tag_rel`, `id_tag`, `id_tutor`, `id_wc`) VALUES (1, 3, 1, 1), (2, 4, 1, 1), (3, 5, 2, 2), (4, 4, 2, 2); CREATE TABLE IF NOT EXISTS `tags` ( `id_tag` int(10) unsigned NOT NULL AUTO_INCREMENT, `tag` varchar(255) DEFAULT NULL, PRIMARY KEY (`id_tag`), UNIQUE KEY `tag` (`tag`), KEY `id_tag` (`id_tag`), KEY `tag_2` (`tag`), KEY `tag_3` (`tag`), KEY `tag_4` (`tag`), FULLTEXT KEY `tag_5` (`tag`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=8 ; INSERT INTO `tags` (`id_tag`, `tag`) VALUES (1, 'Sandeepan'), (2, 'Nath'), (3, 'first'), (4, 'class'), (5, 'new'), (6, 'Bob'), (7, 'Cratchit'); CREATE TABLE IF NOT EXISTS `all_tag_relations` ( `id_tag_rel` int(10) NOT NULL AUTO_INCREMENT, `id_tag` int(10) unsigned NOT NULL DEFAULT '0', `id_tutor` int(10) DEFAULT NULL, `id_wc` int(10) unsigned DEFAULT NULL, PRIMARY KEY (`id_tag_rel`), KEY `All_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_wc` (`id_wc`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; insert into All_Tag_Relations select NULL,id_tag,id_tutor,NULL from Tutors_Tag_Relations; insert into All_Tag_Relations select NULL,id_tag,id_tutor,id_wc from Webclasses_Tag_Relations; Here you can see how easily tutor first name can be edited only in one place. But search has become really difficult, so on being advised to use a Temporary table, I am creating one at every search request, then dumping all the necessary data and then searching from it, I am creating this All_Tag_Relations table at search run time. Here I am just dumping all the data from the two tables Tutors_Tag_Relations and Webclasses_Tag_Relations. But, I am still not able to get classes if I search with tutor name This is the query which searches "first class". Running them on both the systems shows correct results (returns the class with id_wc = 1). SELECT wtagrels.id_wc,SUM(DISTINCT( wtagrels.id_tag =3)) AS key_1_total_matches, SUM(DISTINCT( wtagrels.id_tag =4)) AS key_2_total_matches FROM all_tag_relations AS wtagrels WHERE ( wtagrels.id_tag =3 OR wtagrels.id_tag =4 ) GROUP BY wtagrels.id_wc HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 LIMIT 0, 20 But, searching for "Sandeepan class" works only with the 1st system Here is the query which searches "Sandeepan class" SELECT wtagrels.id_wc,SUM(DISTINCT( wtagrels.id_tag =1)) AS key_1_total_matches, SUM(DISTINCT( wtagrels.id_tag =4)) AS key_2_total_matches FROM all_tag_relations AS wtagrels WHERE ( wtagrels.id_tag =1 OR wtagrels.id_tag =4 ) GROUP BY wtagrels.id_wc HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 LIMIT 0, 20 Can anybody alter this query and somehow do a proper join or something to get correct results. That solves my problem in a nice way. As you can figure out, the reason why it does not work in system 2 is that in system 1, for every class, one additional tag relation linking class and tutor name is present. e.g. for class first class, (records with id_tag_rel 3 and 4) which returns the class on searching with tutor name. So, you see the trade-off between the search and profile edition difficulty with the two systems. How do I overcome both. I have to reach a conclusion soon. So far my reasoning is it is definitely not good from a code maintainability point of view to follow the single tag rel table structure of system one, because in a real system while editing a field like "tutor qualifications", there can be as many records in tag rels table as there are words in qualification of a tutor (one word in a field = one tag relation). Now suppose a tutor has 100 classes. When he edits his qualification, all the tag rel rows corresponding to him are deleted and then as many copies are to be created (as per the new qualification data) as there are classes. This becomes particularly difficult if later more searcheable fields are added. The code cannot be robust. Is the best solution to follow system 2 (edition has to be in one table - no extra work for each and every class) and somehow re-create the all_tag_relations table like system 1 (from the tables tutor_tag_relations and webclasses_tag_relations), creating the extra tutor tag rels for each and every class by a tutor (which is currently missing in system 2's temporary all_tag_relations table). That would be a time consuming logic script. I doubt that table can be recreated without resorting to PHP sript (mysql alone cannot do that). But the problem is that running all this at search time will make search definitely slow. So, how do such systems work? How are such situations handled? I thought about we can run a cron which initiates that PHP script, say every 1 minute and replaces the existing all_tag_relations table as per new tag rels from tutor_tag_relations and webclasses_tag_relations (replaces means creates a new table, deletes the original and renames the new one as all_tag_relations, otherwise search won't work during that period- or is there any better way to that?). Anyway, the result would be that any changes by tutors will reflect in search in the next 1 minute and not immediately. An alternateve would be to initate that PHP script every time a tutor edits his profile. But here again, since many users may edit their profiles concurrently, will the creation of so many tables be a burden and can mysql make the server slow? Any help would be appreciated and working solution will be accepted as answer. Thanks, Sandeepan

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  • Can this Query can be corrected or different table structure needed? (question is clear, detailed, d

    - by sandeepan
    This is a bit lengthy but I have provided sufficient details and kept things very clear. Please see if you can help. (I will surely accept answer if it solves my problem) I am sure a person experienced with this can surely help or suggest me to decide the tables structure. About the system:- There are tutors who create classes A tags based search approach is being followed Tag relations are created/edited when new tutors registers/edits profile data and when tutors create classes (this makes tutors and classes searcheable).For simplicity, let us consider only tutor name and class name are the fields which are matched against search keywords. In this example, I am considering - tutor "Sandeepan Nath" has created a class called "first class" tutor "Bob Cratchit" has created a class called "new class" Desired search results- AND logic to be appied on the search keywords and match against class and tutor data(class name + tutor name), in other words, All those classes be shown such that all the search terms are present in the class name or its tutor name. Example to be clear - Searching "first class" returns class with id_wc = 1. Working Searching "Sandeepan class" should also return class with id_wc = 1. Not working in System 2. Problem with profile editing and searching To tell in one sentence, I am facing a conflict between the ease of profile edition (edition of tag relations when tutor profiles are edited) and the ease of search logic. In the beginning, we had one table structure and search was easy but tag edition logic was very clumsy and unmaintainable(Check System 1 in the section below) . So we created separate tag relations tables to make profile edition simpler but search has become difficult. Please dump the tables so that you can run the search query I have given below and see the results. System 1 (previous system - search easy - profile edition difficult):- Only one table called All_Tag_Relations table had the all the tag relations. The tags table below is common to both systems 1 and 2. CREATE TABLE IF NOT EXISTS `all_tag_relations` ( `id_tag_rel` int(10) NOT NULL AUTO_INCREMENT, `id_tag` int(10) unsigned NOT NULL DEFAULT '0', `id_tutor` int(10) DEFAULT NULL, `id_wc` int(10) unsigned DEFAULT NULL, PRIMARY KEY (`id_tag_rel`), KEY `All_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_wc` (`id_wc`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `all_tag_relations` (`id_tag_rel`, `id_tag`, `id_tutor`, `id_wc`) VALUES (1, 1, 1, NULL), (2, 2, 1, NULL), (3, 1, 1, 1), (4, 2, 1, 1), (5, 3, 1, 1), (6, 4, 1, 1), (7, 6, 2, NULL), (8, 7, 2, NULL), (9, 6, 2, 2), (10, 7, 2, 2), (11, 5, 2, 2), (12, 4, 2, 2); CREATE TABLE IF NOT EXISTS `tags` ( `id_tag` int(10) unsigned NOT NULL AUTO_INCREMENT, `tag` varchar(255) DEFAULT NULL, PRIMARY KEY (`id_tag`), UNIQUE KEY `tag` (`tag`), KEY `id_tag` (`id_tag`), KEY `tag_2` (`tag`), KEY `tag_3` (`tag`), KEY `tag_4` (`tag`), FULLTEXT KEY `tag_5` (`tag`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=8 ; INSERT INTO `tags` (`id_tag`, `tag`) VALUES (1, 'Sandeepan'), (2, 'Nath'), (3, 'first'), (4, 'class'), (5, 'new'), (6, 'Bob'), (7, 'Cratchit'); Please note that for every class, the tag rels of its tutor have to be duplicated. Example, for class with id_wc=1, the tag rel records with id_tag_rel = 3 and 4 are actually extras if you compare with the tag rel records with id_tag_rel = 1 and 2. System 2 (present system - profile edition easy, search difficult) Two separate tables Tutors_Tag_Relations and Webclasses_Tag_Relations have the corresponding tag relations data (Please dump into a separate database)- CREATE TABLE IF NOT EXISTS `tutors_tag_relations` ( `id_tag_rel` int(10) NOT NULL AUTO_INCREMENT, `id_tag` int(10) unsigned NOT NULL DEFAULT '0', `id_tutor` int(10) DEFAULT NULL, PRIMARY KEY (`id_tag_rel`), KEY `All_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `tutors_tag_relations` (`id_tag_rel`, `id_tag`, `id_tutor`) VALUES (1, 1, 1), (2, 2, 1), (3, 6, 2), (4, 7, 2); CREATE TABLE IF NOT EXISTS `webclasses_tag_relations` ( `id_tag_rel` int(10) NOT NULL AUTO_INCREMENT, `id_tag` int(10) unsigned NOT NULL DEFAULT '0', `id_tutor` int(10) DEFAULT NULL, `id_wc` int(10) DEFAULT NULL, PRIMARY KEY (`id_tag_rel`), KEY `webclasses_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_wc` (`id_wc`), KEY `id_tag` (`id_tag`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; INSERT INTO `webclasses_tag_relations` (`id_tag_rel`, `id_tag`, `id_tutor`, `id_wc`) VALUES (1, 3, 1, 1), (2, 4, 1, 1), (3, 5, 2, 2), (4, 4, 2, 2); CREATE TABLE IF NOT EXISTS `tags` ( `id_tag` int(10) unsigned NOT NULL AUTO_INCREMENT, `tag` varchar(255) DEFAULT NULL, PRIMARY KEY (`id_tag`), UNIQUE KEY `tag` (`tag`), KEY `id_tag` (`id_tag`), KEY `tag_2` (`tag`), KEY `tag_3` (`tag`), KEY `tag_4` (`tag`), FULLTEXT KEY `tag_5` (`tag`) ) ENGINE=MyISAM DEFAULT CHARSET=latin1 AUTO_INCREMENT=8 ; INSERT INTO `tags` (`id_tag`, `tag`) VALUES (1, 'Sandeepan'), (2, 'Nath'), (3, 'first'), (4, 'class'), (5, 'new'), (6, 'Bob'), (7, 'Cratchit'); CREATE TABLE IF NOT EXISTS `all_tag_relations` ( `id_tag_rel` int(10) NOT NULL AUTO_INCREMENT, `id_tag` int(10) unsigned NOT NULL DEFAULT '0', `id_tutor` int(10) DEFAULT NULL, `id_wc` int(10) unsigned DEFAULT NULL, PRIMARY KEY (`id_tag_rel`), KEY `All_Tag_Relations_FKIndex1` (`id_tag`), KEY `id_wc` (`id_wc`) ) ENGINE=InnoDB DEFAULT CHARSET=latin1; insert into All_Tag_Relations select NULL,id_tag,id_tutor,NULL from Tutors_Tag_Relations; insert into All_Tag_Relations select NULL,id_tag,id_tutor,id_wc from Webclasses_Tag_Relations; Here you can see how easily tutor first name can be edited only in one place. But search has become really difficult, so on being advised to use a Temporary table, I am creating one at every search request, then dumping all the necessary data and then searching from it, I am creating this All_Tag_Relations table at search run time. Here I am just dumping all the data from the two tables Tutors_Tag_Relations and Webclasses_Tag_Relations. But, I am still not able to get classes if I search with tutor name This is the query which searches "first class". Running them on both the systems shows correct results (returns the class with id_wc = 1). SELECT wtagrels.id_wc,SUM(DISTINCT( wtagrels.id_tag =3)) AS key_1_total_matches, SUM(DISTINCT( wtagrels.id_tag =4)) AS key_2_total_matches FROM all_tag_relations AS wtagrels WHERE ( wtagrels.id_tag =3 OR wtagrels.id_tag =4 ) GROUP BY wtagrels.id_wc HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 LIMIT 0, 20 But, searching for "Sandeepan class" works only with the 1st system Here is the query which searches "Sandeepan class" SELECT wtagrels.id_wc,SUM(DISTINCT( wtagrels.id_tag =1)) AS key_1_total_matches, SUM(DISTINCT( wtagrels.id_tag =4)) AS key_2_total_matches FROM all_tag_relations AS wtagrels WHERE ( wtagrels.id_tag =1 OR wtagrels.id_tag =4 ) GROUP BY wtagrels.id_wc HAVING key_1_total_matches = 1 AND key_2_total_matches = 1 LIMIT 0, 20 Can anybody alter this query and somehow do a proper join or something to get correct results. That solves my problem in a nice way. As you can figure out, the reason why it does not work in system 2 is that in system 1, for every class, one additional tag relation linking class and tutor name is present. e.g. for class first class, (records with id_tag_rel 3 and 4) which returns the class on searching with tutor name. So, you see the trade-off between the search and profile edition difficulty with the two systems. How do I overcome both. I have to reach a conclusion soon. So far my reasoning is it is definitely not good from a code maintainability point of view to follow the single tag rel table structure of system one, because in a real system while editing a field like "tutor qualifications", there can be as many records in tag rels table as there are words in qualification of a tutor (one word in a field = one tag relation). Now suppose a tutor has 100 classes. When he edits his qualification, all the tag rel rows corresponding to him are deleted and then as many copies are to be created (as per the new qualification data) as there are classes. This becomes particularly difficult if later more searcheable fields are added. The code cannot be robust. Is the best solution to follow system 2 (edition has to be in one table - no extra work for each and every class) and somehow re-create the all_tag_relations table like system 1 (from the tables tutor_tag_relations and webclasses_tag_relations), creating the extra tutor tag rels for each and every class by a tutor (which is currently missing in system 2's temporary all_tag_relations table). That would be a time consuming logic script. I doubt that table can be recreated without resorting to PHP sript (mysql alone cannot do that). But the problem is that running all this at search time will make search definitely slow. So, how do such systems work? How are such situations handled? I thought about we can run a cron which initiates that PHP script, say every 1 minute and replaces the existing all_tag_relations table as per new tag rels from tutor_tag_relations and webclasses_tag_relations (replaces means creates a new table, deletes the original and renames the new one as all_tag_relations, otherwise search won't work during that period- or is there any better way to that?). Anyway, the result would be that any changes by tutors will reflect in search in the next 1 minute and not immediately. An alternateve would be to initate that PHP script every time a tutor edits his profile. But here again, since many users may edit their profiles concurrently, will the creation of so many tables be a burden and can mysql make the server slow? Any help would be appreciated and working solution will be accepted as answer. Thanks, Sandeepan

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  • Introducing Data Annotations Extensions

    - by srkirkland
    Validation of user input is integral to building a modern web application, and ASP.NET MVC offers us a way to enforce business rules on both the client and server using Model Validation.  The recent release of ASP.NET MVC 3 has improved these offerings on the client side by introducing an unobtrusive validation library built on top of jquery.validation.  Out of the box MVC comes with support for Data Annotations (that is, System.ComponentModel.DataAnnotations) and can be extended to support other frameworks.  Data Annotations Validation is becoming more popular and is being baked in to many other Microsoft offerings, including Entity Framework, though with MVC it only contains four validators: Range, Required, StringLength and Regular Expression.  The Data Annotations Extensions project attempts to augment these validators with additional attributes while maintaining the clean integration Data Annotations provides. A Quick Word About Data Annotations Extensions The Data Annotations Extensions project can be found at http://dataannotationsextensions.org/, and currently provides 11 additional validation attributes (ex: Email, EqualTo, Min/Max) on top of Data Annotations’ original 4.  You can find a current list of the validation attributes on the afore mentioned website. The core library provides server-side validation attributes that can be used in any .NET 4.0 project (no MVC dependency). There is also an easily pluggable client-side validation library which can be used in ASP.NET MVC 3 projects using unobtrusive jquery validation (only MVC3 included javascript files are required). On to the Preview Let’s say you had the following “Customer” domain model (or view model, depending on your project structure) in an MVC 3 project: public class Customer { public string Email { get; set; } public int Age { get; set; } public string ProfilePictureLocation { get; set; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } When it comes time to create/edit this Customer, you will probably have a CustomerController and a simple form that just uses one of the Html.EditorFor() methods that the ASP.NET MVC tooling generates for you (or you can write yourself).  It should look something like this: With no validation, the customer can enter nonsense for an email address, and then can even report their age as a negative number!  With the built-in Data Annotations validation, I could do a bit better by adding a Range to the age, adding a RegularExpression for email (yuck!), and adding some required attributes.  However, I’d still be able to report my age as 10.75 years old, and my profile picture could still be any string.  Let’s use Data Annotations along with this project, Data Annotations Extensions, and see what we can get: public class Customer { [Email] [Required] public string Email { get; set; }   [Integer] [Min(1, ErrorMessage="Unless you are benjamin button you are lying.")] [Required] public int Age { get; set; }   [FileExtensions("png|jpg|jpeg|gif")] public string ProfilePictureLocation { get; set; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now let’s try to put in some invalid values and see what happens: That is very nice validation, all done on the client side (will also be validated on the server).  Also, the Customer class validation attributes are very easy to read and understand. Another bonus: Since Data Annotations Extensions can integrate with MVC 3’s unobtrusive validation, no additional scripts are required! Now that we’ve seen our target, let’s take a look at how to get there within a new MVC 3 project. Adding Data Annotations Extensions To Your Project First we will File->New Project and create an ASP.NET MVC 3 project.  I am going to use Razor for these examples, but any view engine can be used in practice.  Now go into the NuGet Extension Manager (right click on references and select add Library Package Reference) and search for “DataAnnotationsExtensions.”  You should see the following two packages: The first package is for server-side validation scenarios, but since we are using MVC 3 and would like comprehensive sever and client validation support, click on the DataAnnotationsExtensions.MVC3 project and then click Install.  This will install the Data Annotations Extensions server and client validation DLLs along with David Ebbo’s web activator (which enables the validation attributes to be registered with MVC 3). Now that Data Annotations Extensions is installed you have all you need to start doing advanced model validation.  If you are already using Data Annotations in your project, just making use of the additional validation attributes will provide client and server validation automatically.  However, assuming you are starting with a blank project I’ll walk you through setting up a controller and model to test with. Creating Your Model In the Models folder, create a new User.cs file with a User class that you can use as a model.  To start with, I’ll use the following class: public class User { public string Email { get; set; } public string Password { get; set; } public string PasswordConfirm { get; set; } public string HomePage { get; set; } public int Age { get; set; } } Next, create a simple controller with at least a Create method, and then a matching Create view (note, you can do all of this via the MVC built-in tooling).  Your files will look something like this: UserController.cs: public class UserController : Controller { public ActionResult Create() { return View(new User()); }   [HttpPost] public ActionResult Create(User user) { if (!ModelState.IsValid) { return View(user); }   return Content("User valid!"); } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Create.cshtml: @model NuGetValidationTester.Models.User   @{ ViewBag.Title = "Create"; }   <h2>Create</h2>   <script src="@Url.Content("~/Scripts/jquery.validate.min.js")" type="text/javascript"></script> <script src="@Url.Content("~/Scripts/jquery.validate.unobtrusive.min.js")" type="text/javascript"></script>   @using (Html.BeginForm()) { @Html.ValidationSummary(true) <fieldset> <legend>User</legend> @Html.EditorForModel() <p> <input type="submit" value="Create" /> </p> </fieldset> } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } In the Create.cshtml view, note that we are referencing jquery validation and jquery unobtrusive (jquery is referenced in the layout page).  These MVC 3 included scripts are the only ones you need to enjoy both the basic Data Annotations validation as well as the validation additions available in Data Annotations Extensions.  These references are added by default when you use the MVC 3 “Add View” dialog on a modification template type. Now when we go to /User/Create we should see a form for editing a User Since we haven’t yet added any validation attributes, this form is valid as shown (including no password, email and an age of 0).  With the built-in Data Annotations attributes we can make some of the fields required, and we could use a range validator of maybe 1 to 110 on Age (of course we don’t want to leave out supercentenarians) but let’s go further and validate our input comprehensively using Data Annotations Extensions.  The new and improved User.cs model class. { [Required] [Email] public string Email { get; set; }   [Required] public string Password { get; set; }   [Required] [EqualTo("Password")] public string PasswordConfirm { get; set; }   [Url] public string HomePage { get; set; }   [Integer] [Min(1)] public int Age { get; set; } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now let’s re-run our form and try to use some invalid values: All of the validation errors you see above occurred on the client, without ever even hitting submit.  The validation is also checked on the server, which is a good practice since client validation is easily bypassed. That’s all you need to do to start a new project and include Data Annotations Extensions, and of course you can integrate it into an existing project just as easily. Nitpickers Corner ASP.NET MVC 3 futures defines four new data annotations attributes which this project has as well: CreditCard, Email, Url and EqualTo.  Unfortunately referencing MVC 3 futures necessitates taking an dependency on MVC 3 in your model layer, which may be unadvisable in a multi-tiered project.  Data Annotations Extensions keeps the server and client side libraries separate so using the project’s validation attributes don’t require you to take any additional dependencies in your model layer which still allowing for the rich client validation experience if you are using MVC 3. Custom Error Message and Globalization: Since the Data Annotations Extensions are build on top of Data Annotations, you have the ability to define your own static error messages and even to use resource files for very customizable error messages. Available Validators: Please see the project site at http://dataannotationsextensions.org/ for an up-to-date list of the new validators included in this project.  As of this post, the following validators are available: CreditCard Date Digits Email EqualTo FileExtensions Integer Max Min Numeric Url Conclusion Hopefully I’ve illustrated how easy it is to add server and client validation to your MVC 3 projects, and how to easily you can extend the available validation options to meet real world needs. The Data Annotations Extensions project is fully open source under the BSD license.  Any feedback would be greatly appreciated.  More information than you require, along with links to the source code, is available at http://dataannotationsextensions.org/. Enjoy!

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  • The Incremental Architect&acute;s Napkin - #2 - Balancing the forces

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/06/02/the-incremental-architectacutes-napkin---2---balancing-the-forces.aspxCategorizing requirements is the prerequisite for ecconomic architectural decisions. Not all requirements are created equal. However, to truely understand and describe the requirement forces pulling on software development, I think further examination of the requirements aspects is varranted. Aspects of Functionality There are two sides to Functionality requirements. It´s about what a software should do. I call that the Operations it implements. Operations are defined by expressions and control structures or calls to frameworks of some sort, i.e. (business) logic statements. Operations calculate, transform, aggregate, validate, send, receive, load, store etc. Operations are about behavior; they take input and produce output by considering state. I´m not using the term “function” here, because functions - or methods or sub-programs - are not necessary to implement Operations. Functions belong to a different sub-aspect of requirements (see below). Operations alone are not enough, though, to make a customer happy with regard to his/her Functionality requirements. Only correctly implemented Operations provide full value. This should make clear, why testing is so important. And not just manual tests during development of some operational feature, but automated tests. Because only automated tests scale when over time the number of operations increases. Without automated tests there is no guarantee formerly correct operations are still correct after more got added. To retest all previous operations manually is infeasible. So whoever relies just on manual tests is not really balancing the two forces Operations and Correctness. With manual tests more weight is put on the side of the scale of Operations. That might be ok for a short period of time - but in the long run it will bite you. You need to plan for Correctness in the long run from the first day of your project on. Aspects of Quality As important as Functionality is, it´s not the driver for software development. No software has ever been written to just implement some operation in code. We don´t need computers just to do something. All computers can do with software we can do without them. Well, at least given enough time and resources. We could calculate the most complex formulas without computers. We could do auctions with millions of people without computers. The only reason we want computers to help us with this and a million other Operations is… We don´t want to wait for the results very long. Or we want less errors. Or we want easier accessability to complicated solutions. So the main reason for customers to buy/order software is some Quality. They want some Functionality with a higher Quality (e.g. performance, scalability, usability, security…) than without the software. But Qualities come in at least two flavors: Most important are Primary Qualities. That´s the Qualities software truely is written for. Take an online auction website for example. Its Primary Qualities are performance, scalability, and usability, I´d say. Auctions should come within reach of millions of people; setting up an auction should be very easy; finding a suitable auction and bidding on it should be as fast as possible. Only if those Qualities have been implemented does security become relevant. A secure auction website is important - but not as important as a fast auction website. Nobody would want to use the most secure auction website if it was unbearably slow. But there would be people willing to use the fastest auction website even it was lacking security. That´s why security - with regard to online auction software - is not a Primary Quality, but just a Secondary Quality. It´s a supporting quality, so to speak. It does not deliver value by itself. With a password manager software this might be different. There security might be a Primary Quality. Please get me right: I don´t want to denigrate any Quality. There´s a long list of non-functional requirements at Wikipedia. They are all created equal - but that does not mean they are equally important for all software projects. When confronted with Quality requirements check with the customer which are primary and which are secondary. That will help to make good economical decisions when in a crunch. Resources are always limited - but requirements are a bottomless ocean. Aspects of Security of Investment Functionality and Quality are traditionally the requirement aspects cared for most - by customers and developers alike. Even today, when pressure rises in a project, tunnel vision will focus on them. Any measures to create and hold up Security of Investment (SoI) will be out of the window pretty quickly. Resistance to customers and/or management is futile. As long as SoI is not placed on equal footing with Functionality and Quality it´s bound to suffer under pressure. To look closer at what SoI means will help to become more conscious about it and make customers and management aware of the risks of neglecting it. SoI to me has two facets: Production Efficiency (PE) is about speed of delivering value. Customers like short response times. Short response times mean less money spent. So whatever makes software development faster supports this requirement. This must not lead to duct tape programming and banging out features by the dozen, though. Because customers don´t just want Operations and Quality, but also Correctness. So if Correctness gets compromised by focussing too much on Production Efficiency it will fire back. Customers want PE not just today, but over the whole course of a software´s lifecycle. That means, it´s not just about coding speed, but equally about code quality. If code quality leads to rework the PE is on an unsatisfactory level. Also if code production leads to waste it´s unsatisfactory. Because the effort which went into waste could have been used to produce value. Rework and waste cost money. Rework and waste abound, however, as long as PE is not addressed explicitly with management and customers. Thanks to the Agile and Lean movements that´s increasingly the case. Nevertheless more could and should be done in many teams. Each and every developer should keep in mind that Production Efficiency is as important to the customer as Functionality and Quality - whether he/she states it or not. Making software development more efficient is important - but still sooner or later even agile projects are going to hit a glas ceiling. At least as long as they neglect the second SoI facet: Evolvability. Delivering correct high quality functionality in short cycles today is good. But not just any software structure will allow this to happen for an indefinite amount of time.[1] The less explicitly software was designed the sooner it´s going to get stuck. Big ball of mud, monolith, brownfield, legacy code, technical debt… there are many names for software structures that have lost the ability to evolve, to be easily changed to accomodate new requirements. An evolvable code base is the opposite of a brownfield. It´s code which can be easily understood (by developers with sufficient domain expertise) and then easily changed to accomodate new requirements. Ideally the costs of adding feature X to an evolvable code base is independent of when it is requested - or at least the costs should only increase linearly, not exponentially.[2] Clean Code, Agile Architecture, and even traditional Software Engineering are concerned with Evolvability. However, it seems no systematic way of achieving it has been layed out yet. TDD + SOLID help - but still… When I look at the design ability reality in teams I see much room for improvement. As stated previously, SoI - or to be more precise: Evolvability - can hardly be measured. Plus the customer rarely states an explicit expectation with regard to it. That´s why I think, special care must be taken to not neglect it. Postponing it to some large refactorings should not be an option. Rather Evolvability needs to be a core concern for every single developer day. This should not mean Evolvability is more important than any of the other requirement aspects. But neither is it less important. That´s why more effort needs to be invested into it, to bring it on par with the other aspects, which usually are much more in focus. In closing As you see, requirements are of quite different kinds. To not take that into account will make it harder to understand the customer, and to make economic decisions. Those sub-aspects of requirements are forces pulling in different directions. To improve performance might have an impact on Evolvability. To increase Production Efficiency might have an impact on security etc. No requirement aspect should go unchecked when deciding how to allocate resources. Balancing should be explicit. And it should be possible to trace back each decision to a requirement. Why is there a null-check on parameters at the start of the method? Why are there 5000 LOC in this method? Why are there interfaces on those classes? Why is this functionality running on the threadpool? Why is this function defined on that class? Why is this class depending on three other classes? These and a thousand more questions are not to mean anything should be different in a code base. But it´s important to know the reason behind all of these decisions. Because not knowing the reason possibly means waste and having decided suboptimally. And how do we ensure to balance all requirement aspects? That needs practices and transparency. Practices means doing things a certain way and not another, even though that might be possible. We´re dealing with dangerous tools here. Like a knife is a dangerous tool. Harm can be done if we use our tools in just any way at the whim of the moment. Over the centuries rules and practices have been established how to use knifes. You don´t put them in peoples´ legs just because you´re feeling like it. You hand over a knife with the handle towards the receiver. You might not even be allowed to cut round food like potatos or eggs with it. The same should be the case for dangerous tools like object-orientation, remote communication, threads etc. We need practices to use them in a way so requirements are balanced almost automatically. In addition, to be able to work on software as a team we need transparency. We need means to share our thoughts, to work jointly on mental models. So far our tools are focused on working with code. Testing frameworks, build servers, DI containers, intellisense, refactoring support… That´s all nice and well. I don´t want to miss any of that. But I think it´s not enough. We´re missing mental tools, tools for making thinking and talking about software (independently of code) easier. You might think, enough of such tools already exist like all those UML diagram types or Flow Charts. But then, isn´t it strange, hardly any team is using them to design software? Or is that just due to a lack of education? I don´t think so. It´s a matter value/weight ratio: the current mental tools are too heavy weight compared to the value they deliver. So my conclusion is, we need lightweight tools to really be able to balance requirements. Software development is complex. We need guidance not to forget important aspects. That´s like with flying an airplane. Pilots don´t just jump in and take off for their destination. Yes, there are times when they are “flying by the seats of their pants”, when they are just experts doing thing intuitively. But most of the time they are going through honed practices called checklist. See “The Checklist Manifesto” for very enlightening details on this. Maybe then I should say it like this: We need more checklists for the complex businss of software development.[3] But that´s what software development mostly is about: changing software over an unknown period of time. It needs to be corrected in order to finally provide promised operations. It needs to be enhanced to provide ever more operations and qualities. All this without knowing when it´s going to stop. Probably never - until “maintainability” hits a wall when the technical debt is too large, the brownfield too deep. Software development is not a sprint, is not a marathon, not even an ultra marathon. Because to all this there is a foreseeable end. Software development is like continuously and foreever running… ? And sometimes I dare to think that costs could even decrease over time. Think of it: With each feature a software becomes richer in functionality. So with each additional feature the chance of there being already functionality helping its implementation increases. That should lead to less costs of feature X if it´s requested later than sooner. X requested later could stand on the shoulders of previous features. Alas, reality seems to be far from this despite 20+ years of admonishing developers to think in terms of reusability.[1] ? Please don´t get me wrong: I don´t want to bog down the “art” of software development with heavyweight practices and heaps of rules to follow. The framework we need should be lightweight. It should not stand in the way of delivering value to the customer. It´s purpose is even to make that easier by helping us to focus and decreasing waste and rework. ?

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  • Abstracting functionality

    - by Ralf Westphal
    Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/08/22/abstracting-functionality.aspxWhat is more important than data? Functionality. Yes, I strongly believe we should switch to a functionality over data mindset in programming. Or actually switch back to it. Focus on functionality Functionality once was at the core of software development. Back when algorithms were the first thing you heard about in CS classes. Sure, data structures, too, were important - but always from the point of view of algorithms. (Niklaus Wirth gave one of his books the title “Algorithms + Data Structures” instead of “Data Structures + Algorithms” for a reason.) The reason for the focus on functionality? Firstly, because software was and is about doing stuff. Secondly because sufficient performance was hard to achieve, and only thirdly memory efficiency. But then hardware became more powerful. That gave rise to a new mindset: object orientation. And with it functionality was devalued. Data took over its place as the most important aspect. Now discussions revolved around structures motivated by data relationships. (John Beidler gave his book the title “Data Structures and Algorithms: An Object Oriented Approach” instead of the other way around for a reason.) Sure, this data could be embellished with functionality. But nevertheless functionality was second. When you look at (domain) object models what you mostly find is (domain) data object models. The common object oriented approach is: data aka structure over functionality. This is true even for the most modern modeling approaches like Domain Driven Design. Look at the literature and what you find is recommendations on how to get data structures right: aggregates, entities, value objects. I´m not saying this is what object orientation was invented for. But I´m saying that´s what I happen to see across many teams now some 25 years after object orientation became mainstream through C++, Delphi, and Java. But why should we switch back? Because software development cannot become truly agile with a data focus. The reason for that lies in what customers need first: functionality, behavior, operations. To be clear, that´s not why software is built. The purpose of software is to be more efficient than the alternative. Money mainly is spent to get a certain level of quality (e.g. performance, scalability, security etc.). But without functionality being present, there is nothing to work on the quality of. What customers want is functionality of a certain quality. ASAP. And tomorrow new functionality needs to be added, existing functionality needs to be changed, and quality needs to be increased. No customer ever wanted data or structures. Of course data should be processed. Data is there, data gets generated, transformed, stored. But how the data is structured for this to happen efficiently is of no concern to the customer. Ask a customer (or user) whether she likes the data structured this way or that way. She´ll say, “I don´t care.” But ask a customer (or user) whether he likes the functionality and its quality this way or that way. He´ll say, “I like it” (or “I don´t like it”). Build software incrementally From this very natural focus of customers and users on functionality and its quality follows we should develop software incrementally. That´s what Agility is about. Deliver small increments quickly and often to get frequent feedback. That way less waste is produced, and learning can take place much easier (on the side of the customer as well as on the side of developers). An increment is some added functionality or quality of functionality.[1] So as it turns out, Agility is about functionality over whatever. But software developers’ thinking is still stuck in the object oriented mindset of whatever over functionality. Bummer. I guess that (at least partly) explains why Agility always hits a glass ceiling in projects. It´s a clash of mindsets, of cultures. Driving software development by demanding small increases in functionality runs against thinking about software as growing (data) structures sprinkled with functionality. (Excuse me, if this sounds a bit broad-brush. But you get my point.) The need for abstraction In the end there need to be data structures. Of course. Small and large ones. The phrase functionality over data does not deny that. It´s not functionality instead of data or something. It´s just over, i.e. functionality should be thought of first. It´s a tad more important. It´s what the customer wants. That´s why we need a way to design functionality. Small and large. We need to be able to think about functionality before implementing it. We need to be able to reason about it among team members. We need to be able to communicate our mental models of functionality not just by speaking about them, but also on paper. Otherwise reasoning about it does not scale. We learned thinking about functionality in the small using flow charts, Nassi-Shneiderman diagrams, pseudo code, or UML sequence diagrams. That´s nice and well. But it does not scale. You can use these tools to describe manageable algorithms. But it does not work for the functionality triggered by pressing the “1-Click Order” on an amazon product page for example. There are several reasons for that, I´d say. Firstly, the level of abstraction over code is negligible. It´s essentially non-existent. Drawing a flow chart or writing pseudo code or writing actual code is very, very much alike. All these tools are about control flow like code is.[2] In addition all tools are computationally complete. They are about logic which is expressions and especially control statements. Whatever you code in Java you can fully (!) describe using a flow chart. And then there is no data. They are about control flow and leave out the data altogether. Thus data mostly is assumed to be global. That´s shooting yourself in the foot, as I hope you agree. Even if it´s functionality over data that does not mean “don´t think about data”. Right to the contrary! Functionality only makes sense with regard to data. So data needs to be in the picture right from the start - but it must not dominate the thinking. The above tools fail on this. Bottom line: So far we´re unable to reason in a scalable and abstract manner about functionality. That´s why programmers are so driven to start coding once they are presented with a problem. Programming languages are the only tool they´ve learned to use to reason about functional solutions. Or, well, there might be exceptions. Mathematical notation and SQL may have come to your mind already. Indeed they are tools on a higher level of abstraction than flow charts etc. That´s because they are declarative and not computationally complete. They leave out details - in order to deliver higher efficiency in devising overall solutions. We can easily reason about functionality using mathematics and SQL. That´s great. Except for that they are domain specific languages. They are not general purpose. (And they don´t scale either, I´d say.) Bummer. So to be more precise we need a scalable general purpose tool on a higher than code level of abstraction not neglecting data. Enter: Flow Design. Abstracting functionality using data flows I believe the solution to the problem of abstracting functionality lies in switching from control flow to data flow. Data flow very naturally is not about logic details anymore. There are no expressions and no control statements anymore. There are not even statements anymore. Data flow is declarative by nature. With data flow we get rid of all the limiting traits of former approaches to modeling functionality. In addition, nomen est omen, data flows include data in the functionality picture. With data flows, data is visibly flowing from processing step to processing step. Control is not flowing. Control is wherever it´s needed to process data coming in. That´s a crucial difference and needs some rewiring in your head to be fully appreciated.[2] Since data flows are declarative they are not the right tool to describe algorithms, though, I´d say. With them you don´t design functionality on a low level. During design data flow processing steps are black boxes. They get fleshed out during coding. Data flow design thus is more coarse grained than flow chart design. It starts on a higher level of abstraction - but then is not limited. By nesting data flows indefinitely you can design functionality of any size, without losing sight of your data. Data flows scale very well during design. They can be used on any level of granularity. And they can easily be depicted. Communicating designs using data flows is easy and scales well, too. The result of functional design using data flows is not algorithms (too low level), but processes. Think of data flows as descriptions of industrial production lines. Data as material runs through a number of processing steps to be analyzed, enhances, transformed. On the top level of a data flow design might be just one processing step, e.g. “execute 1-click order”. But below that are arbitrary levels of flows with smaller and smaller steps. That´s not layering as in “layered architecture”, though. Rather it´s a stratified design à la Abelson/Sussman. Refining data flows is not your grandpa´s functional decomposition. That was rooted in control flows. Refining data flows does not suffer from the limits of functional decomposition against which object orientation was supposed to be an antidote. Summary I´ve been working exclusively with data flows for functional design for the past 4 years. It has changed my life as a programmer. What once was difficult is now easy. And, no, I´m not using Clojure or F#. And I´m not a async/parallel execution buff. Designing the functionality of increments using data flows works great with teams. It produces design documentation which can easily be translated into code - in which then the smallest data flow processing steps have to be fleshed out - which is comparatively easy. Using a systematic translation approach code can mirror the data flow design. That way later on the design can easily be reproduced from the code if need be. And finally, data flow designs play well with object orientation. They are a great starting point for class design. But that´s a story for another day. To me data flow design simply is one of the missing links of systematic lightweight software design. There are also other artifacts software development can produce to get feedback, e.g. process descriptions, test cases. But customers can be delighted more easily with code based increments in functionality. ? No, I´m not talking about the endless possibilities this opens for parallel processing. Data flows are useful independently of multi-core processors and Actor-based designs. That´s my whole point here. Data flows are good for reasoning and evolvability. So forget about any special frameworks you might need to reap benefits from data flows. None are necessary. Translating data flow designs even into plain of Java is possible. ?

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  • EMC ESRS stops working when it is VMotioned

    - by makerofthings7
    EMC is on site and told me: The ESRS SAN monitoring solution will cease to function if that host is VMotioned In case anyone doesn't know, the ESRS is a dial home solution that works over IP. An EMC SecureID is required to add or modify the list of devices that are monitored. The ESRS software is installed on the customer premises. Question If ESRS truly fails to work, as the EMC engineer stated, and based on our customer experience, what is it within VMWare that is exposed to the virtualized host that allows this behavior to happen?

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  • Sending email from various domains

    - by IMHO
    We are building hosted software service that is used by multiple customers. These customers want to communicate with their customers (end customer). So, today we send it from our domain: example.com However, we would like to send email to come from their specific domains. When we put their customer emails in Reply-To - it shows up as "on behalf" in clients like outlook. What are the ways to send email from their domain without installing software on their network?

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  • DB2 runstats not working for xml columns

    - by Keshav Prasad
    Hello, I am running runstats command to update the runtime statistics of a particular table called "CUSTOMER" in DB2. The customer has two columns- CID (integer) and INFO (xml column). After running the command, if I look into the SYSCOLDIST table, the information for column CID is populated correctly. But there is nothing filled for the INFO xml column. The same happens with a different table that has xml columns. Please help.. Thanks, -Keshav

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  • Measuring talk time.

    - by Workshop Alex
    Situation: a financial advisor starts talking to a customer after starting a timer. When the conversation ends, he stops the timer and the amount of time is added to a log file with information about the customer. Does such an application already exist?

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  • Multiple subdomains resolving to one domain?

    - by Matt
    I'm trying to host an application, but allow the customer to use their own sub domain so that it does not confuse their own customers. So for example, by application would run on app.mydomain.com, but my customer would access it via their own subdomain (app.somedomain.com and/or app.anotherdomain.com). Is this even possible? (Possibly relevant information: my application is hosted on media temple and uses Apache) Thanks!

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  • Domain Forwarding | A Magento Store

    - by WaZ
    I have installed Magento inside a folder called magento. The URL of the site currently looks like this: http://gios.azamdevelopment.co.uk/magento/ We want our domain forwarded to the above URL and moreover, any links relative should work as well. e.g. http://gios.azamdevelopment.co.uk/magento/customer/account/login/ should ideally be www.giosconcept.com/customer/account/login and so forth. Thanks very much.

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  • Domain Forwarding | A Magento Store

    - by WaZ
    I have installed Magento inside a folder called magento. The URL of the site currently looks like this: http://gios.azamdevelopment.co.uk/magento/ We want our domain forwarded to the above URL and moreover, any links relative should work as well. e.g. http://gios.azamdevelopment.co.uk/magento/customer/account/login/ should ideally be www.giosconcept.com/customer/account/login and so forth. Thanks very much.

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  • what are the components you can install on RHEL?

    - by user16654
    I just got a question from a customer(actually from a customer to my manager then to me) and he is asking the following question: What are the components that were installed with RHEL? It may sound like a silly question but to me it sounds vague. The main thing I am thinking about now is during install you can select three components: webserver software development and virtualisation. Could they be asking fro something else?

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  • Bidirectional Serialization with Linq

    - by Andy
    Anyone know why only undirectional serialization is supported in the Linq designer? Consider the following example: Say we have a Customer who requested an Order containing Products. We set the Serialization Mode in the Linq designer to Unidirectional to enable serialization. When looking at the code for the Order object, the DataMember attribute is added to all its internal properties such as ID,OrderNumber, etc. and also to the EntitySet of Products, but not to Customer. One can get around this by manually adding the DataMember attribute to Customer, but this becomes quite cumbersome when there's loads of entities in the database.

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  • Symfony dynamic subdomains

    - by Jamie
    Hi all, I'm trying to match subdomains to a customer id in symfony. i.e. i have customer1.example.com and customer2.example.com Domains are stored in a table. When a user goes to customer1.example.com, I would like to get the subdomain, look up the domain name in the database, once matched, it will then deploy the app config for that customer and then store the customer_Id in a global attribute so i know exactly which customer I'm dealing with througout the whole application. The virtual host will have the relevant wildcard servername. Have you managed to achieve this, and if so, how? If not, any ideas would be a great help! I'm thinking about using a filter to do it. :-)

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  • ETL Operation - Return Primary Key

    - by user302254
    I am using Talend to populate a data warehouse. My job is writing customer data to a dimension table and transaction data to the fact table. The surrogate key (p_key) on the fact table is auto-incrementing. When I insert a new customer, I need my fact table to reflect the id of the related customer. As I mentioned my p_key is auto auto_incrementing so I can't just insert an arbitrary value for the p_key. Any thought on how I can insert a row into my dimension table and still retrieve the primary key to reference in my fact record? Thanks.

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  • Inline editing of ManyToMany relation in Django

    - by vorpyg
    After working through the Django tutorial I'm now trying to build a very simple invoicing application. I want to add several Products to an Invoice, and to specify the quantity of each product in the Invoice form in the Django admin. Now I've to create a new Product object if I've got different quantites of the same Product. Right now my models look like this (Company and Customer models left out): class Product(models.Model): description = models.TextField() quantity = models.IntegerField() price = models.DecimalField(max_digits=10,decimal_places=2) tax = models.ForeignKey(Tax) class Invoice(models.Model): company = models.ForeignKey(Company) customer = models.ForeignKey(Customer) products = models.ManyToManyField(Product) invoice_no = models.IntegerField() invoice_date = models.DateField(auto_now=True) due_date = models.DateField(default=datetime.date.today() + datetime.timedelta(days=14)) I guess the quantity should be left out of the Product model, but how can I make a field for it in the Invoice model?

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  • Test Case Design and Responsibility

    - by Sakamoto Kazuma
    So it seems like a lot of people are playing the blame game around where I work, and it brings up an interesting question. Knowns: Requirements team writes requirements for product. Developers create their own unit tests out of requirements. Testing team creates their general tests out of requirements and past customer issues. Product released if and only if X% of testcases from Testing team passes Customer response team gets bugs from the field, and lets the testing team know about these issues. Question: If the customer ends up filing a lot of defects, who is to blame? Is it the Testing team for not covering those? Or is it the requirements team for not writing better requirements? And how does one improve upon the system?

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  • Passing to service custom class instance in WCF

    - by hgulyan
    Hi, I have my custom class Customer with its properties. I added DataContract mark above the class and DataMember to properties and it was working fine, but I'm calling a service class's function, passing customer instance as parameter and some of my properties get 0 values. While debugging I can see my properties values and after it gets to the function, some properties' values are 0. Why it can be so? There's no code between this two actions. DataContract mark workes fine, everything's ok. Any suggestions on this issue? I tried to change ByRef to ByVal, but it doesn't change anything. Why it would pass other values right and some of integer types just 0? Maybe the answer is simple, but I can't figure it out. Thank You. _ Public Class Customer Private Type_of_clientField As Integer = -1 _ Public Property type_of_client() As Integer Get Return Type_of_clientField End Get Set(ByVal value As Integer) Type_of_clientField = value End Set End Property End Class _ _

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