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  • Ghost in the machine

    - by GrumpyOldDBA
    Well it does relate to ghosts, in this case dbGhost, http://dbghost.com/    which is what this post is about. Ghost creates databases on the fly, something I personally don’t like too much, which it then compares to a “base” database to produce release scripts. ( The brief description ). As with all things sometimes all is not well and the server is left with a number of ghost created databases so I have to have a job to delete these every night before backups, it’s not difficult to code...(read more)

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  • How should I study programming languages?

    - by gcc
    I am a student of computer engineering. I have never done any programming before, and as you can understand, I don't know how to study it or how to make my own programs. My English is weak [edited for clarity - ed], and so if you don't like the choices I list, please feel free to provide others. How should I study? How should I learn programming languages? Study completely from a book. Don't study from a book, just try writing code. A mix of the two; study from a book, then try writing code. Study half the book, then write the code by hand on paper. Listed to the teacher, then try to solve general problems (those not from any specific chapter).

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  • Financial institutions build predictive models using Oracle R Enterprise to speed model deployment

    - by Mark Hornick
    See the Oracle press release, Financial Institutions Leverage Metadata Driven Modeling Capability Built on the Oracle R Enterprise Platform to Accelerate Model Deployment and Streamline Governance for a description where a "unified environment for analytics data management and model lifecycle management brings the power and flexibility of the open source R statistical platform, delivered via the in-database Oracle R Enterprise engine to support open standards compliance." Through its integration with Oracle R Enterprise, Oracle Financial Services Analytical Applications provides "productivity, management, and governance benefits to financial institutions, including the ability to: Centrally manage and control models in a single, enterprise model repository, allowing for consistent management and application of security and IT governance policies across enterprise assets Reuse models and rapidly integrate with applications by exposing models as services Accelerate development with seeded models and common modeling and statistical techniques available out-of-the-box Cut risk and speed model deployment by testing and tuning models with production data while working within a safe sandbox Support compliance with regulatory requirements by carrying out comprehensive stress testing, which captures the effects of adverse risk events that are not estimated by standard statistical and business models. This approach supplements the modeling process and supports compliance with the Pillar I and the Internal Capital Adequacy Assessment Process stress testing requirements of the Basel II Accord Improve performance by deploying and running models co-resident with data. Oracle R Enterprise engines run in database, virtually eliminating the need to move data to and from client machines, thereby reducing latency and improving security"

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  • Oracle Tutor - Is Anyone Reading Your Documentation?

    - by mary.keane
    If you are responsible for documenting your business practices, wouldn't it be nice to know if anyone is using the documentation? If the employees find it useful? You might want to consider surveying the users of the documentation on a regular basis. There are a number of free survey tools online (search for "free survey tools"), and you can have a survey ready in a matter of minutes. It's as simple as gathering a list of questions and a list of email addresses. For the questions, here are some suggestions. How often do you access the policy and procedure site? How useful is the site? How easy is it to navigate the site? How often are your questions answered on the site? What suggestions do you have to make the site more useful? You may want to consider just asking a few questions each month so that employees can complete the survey in less than 5 minutes (you'll get more responses). Make sure you have several comment boxes in the survey so that the employees can give suggestions. As the users of your documentation, the employees may have some terrific ideas that will enhance the usability of your policy and procedure site. It would be great to hear your suggestions for how to survey the users of your documentation. Mary R. Keane Senior Development Manager, Oracle BPM and Tutor

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  • Should one comment differently in functional languages

    - by Tom Squires
    I'm just getting started with functional programming and I'm wondering the correct way to comment my code. It seems a little redundant to comment a short function as the names and signature already should tell you everything you need to know. Commenting larger functions also seems a little redundant since they are generally comprised of smaller self-descriptive functions. What is the correct way to comment a functional program? Should I use the same approach as in iterative programming?

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  • Why do we keep using CSV?

    - by Stephen
    Why do we keep using CSV? I recently made a shift to working the health domain and despite the wonderful work in data transfer standards, all data transfer is in CSV, both for reporting to external organisations, and for data migrations when implementing new systems. Unfortunately the use of CSV is the cause of the endless repetition of the same stupid errors, with the same waste of developer time. (bad escaping, failing to handle null fields etc.) I know we can do better, and anything between JSON and XML (depending on the instance) would be fine. (Most of the time this is data going from one MS SQLserver 2005 to another!) I feel as if each time I see this happening I am literally watching one developer waste anothers time. So why do we keep shafting each other? When will we stop?

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  • WEBCAST: Strategies for Managing the Oracle Database Lifecycle

    - by Scott McNeil
    Thursday November 110:00 a.m. PST / 1:00 p.m. EST Join us for a live Webcast and see how Oracle Enterprise Manager 12c makes database lifecycle management easier. You’ll learn how to: Simplify database configurations thanks to extensive automation for discovery and change detection Improve IT service levels with Oracle’s next-generation database patching and provisioning automation Ensure consistency and compliance with comprehensive database change management Register today. Stay Connected: Twitter | Facebook | YouTube | Linkedin | NewsletterDownload the Oracle Enterprise Manager Cloud Control12c Mobile app

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  • Let your Signature Experience drive IT-decision making

    - by Tania Le Voi
    Today’s CIO job description:  ‘’Align IT infrastructure and solutions with business goals and objectives ; AND while doing so reduce costs; BUT ALSO, be innovative, ensure the architectures are adaptable and agile as we need to act today on the changes that we may request tomorrow.”   Sound like an unachievable request? The fact is, reality dictates that CIO’s are put under this type of pressure to deliver more with less. In a past career phase I spent a few years as an IT Relationship Manager for a large Insurance company. This is a role that we see all too infrequently in many of our customers, and it’s a shame.  The purpose of this role was to build a bridge, a relationship between IT and the business. Key to achieving that goal was to ensure the same language was being spoken and more importantly that objectives were commonly understood - hence service and projects were delivered to time, to budget and actually solved the business problems. In reality IT and the business are already married, but the relationship is most often defined as ‘supplier’ of IT rather than a ‘trusted partner’. To deliver business value they need to understand how to work together effectively to attain this next level of partnership. The Business cannot compete if they do not get a new product to market ahead of the competition, or for example act in a timely manner to address a new industry problem such as a legislative change. An even better example is when the Application or Service fails and the Business takes a hit by bad publicity, being trending topics on social media and losing direct revenue from online channels. For this reason alone Business and IT need the alignment of their priorities and deliverables now more than ever! Take a look at Forrester’s recent study that found ‘many IT respondents considering themselves to be trusted partners of the business but their efforts are impaired by the inadequacy of tools and organizations’.  IT Meet the Business; Business Meet IT So what is going on? We talk about aligning the business with IT but the reality is it’s difficult to do. Like any relationship each side has different goals and needs and language can be a barrier; business vs. technology jargon! What if we could translate the needs of both sides into actionable information, backed by data both sides understand, presented in a meaningful way?  Well now we can with the Business-Driven Application Management capabilities in Oracle Enterprise Manager 12cR2! Enterprise Manager’s Business-Driven Application Management capabilities provide the information that IT needs to understand the impact of its decisions on business criteria.  No longer does IT need to be focused solely on speeds and feeds, performance and throughput – now IT can understand IT’s impact on business KPIs like inventory turns, order-to-cash cycle, pipeline-to-forecast, and similar.  Similarly, now the line of business can understand which IT services are most critical for the KPIs they care about. There are a good deal of resources on Oracle Technology Network that describe the functionality of these products, so I won’t’ rehash them here.  What I want to talk about is what you do with these products. What’s next after we meet? Where do you start? Step 1:  Identify the Signature Experience. This is THE business process (or set of processes) that is core to the business, the one that drives the economic engine, the process that a customer recognises the company brand for, reputation, the customer experience, the process that a CEO would state as his number one priority. The crème de la crème of your business! Once you have nailed this it gets easy as Enterprise Manager 12c makes it easy. Step 2:  Map the Signature Experience to underlying IT.  Taking the signature experience, map out the touch points of the components that play a part in ensuring this business transaction is successful end to end, think of it like mapping out a critical path; the applications, middleware, databases and hardware. Use the wealth of Enterprise Manager features such as Systems, Services, Business Application Targets and Business Transaction Management (BTM) to assist you. Adding Real User Experience Insight (RUEI) into the mix will make the end to end customer satisfaction story transparent. Work with the business and define meaningful key performance indicators (KPI’s) and thresholds to enable you to report and action upon. Step 3:  Observe the data over time.  You now have meaningful insight into every step enabling your signature experience and you understand the implication of that experience on your underlying IT.  Watch if for a few months, see what happens and reconvene with your business stakeholders and set clear and measurable targets which can re-define service levels.  Step 4:  Change the information about which you and the business communicate.  It’s amazing what happens when you and the business speak the same language.  You’ll be able to make more informed business and IT decisions. From here IT can identify where/how budget is spent whether on the level of support, performance, capacity, HA, DR, certification etc. IT SLA’s no longer need be focused on metrics such as %availability but structured around business process requirements. The power of this way of thinking doesn’t end here. IT staff get to see and understand how their own role contributes to the business making them accountable for the business service. Take a step further and appraise your staff on the business competencies that are linked to the service availability. For the business, the language barrier is removed by producing targeted reports on the signature experience core to the business and therefore key to the CEO. Chargeback or show back becomes easier to justify as the ‘cost of day per outage’ can be more easily calculated; the business will be able to translate the cost to the business to the cost/value of the underlying IT that supports it. Used this way, Oracle Enterprise Manager 12c is a key enabler to a harmonious relationship between the end customer the business and IT to deliver ultimate service and satisfaction. Just engage with the business upfront, make the signature experience visible and let Enterprise Manager 12c do the rest. In the next blog entry we will cover some of the Enterprise Manager features mentioned to enable you to implement this new way of working.  

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  • Best practice Java - String array constant and indexing it

    - by Pramod
    For string constants its usual to use a class with final String values. But whats the best practice for storing string array. I want to store different categories in a constant array and everytime a category has been selected, I want to know which category it belongs to and process based on that. Addition : To make it more clear, I have a categories A,B,C,D,E which is a constant array. Whenever a user clicks one of the items(button will have those texts) I should know which item was clicked and do processing on that. I can define an enum(say cat) and everytime do if clickedItem == cat.A .... else if clickedItem = cat.B .... else if .... or even register listeners for each item seperately. But I wanted to know the best practice for doing handling these kind of problems.

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  • Summer Upgrade Workshops are Open!

    - by roy.swonger
    The listing of upcoming events is located in the right sidebar of the main blog page, down below the flag counter. If you haven't checked out our schedule lately, you might be surprised at how active we will be with travel this summer. Coming up next week will be upgrade workshops in the USA (St. Louis and Minneapolis) followed by a pair in Canada (Toronto and Montreal) and then two in Europe (Brussels and Utrecht). Make your plans now to attend an upgrade workshop in your area. As you can see from the long list of planned events, it is very likely that Mike or I will be coming to your area sometime soon!

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  • Hosting several HTTP servers on single domain name

    - by Nakilon
    Several people have got a single domain name server.company.com server, where they are now supposed to host their infrastructure or temporal projects, written in different ways even in different programming languages. How do they divide the domain? Split into subdomains: john.server.company.com, kate.server.company.com, etc. This would need a lot of admins' assistance, time, etc. -- there would be no way for John and Kate to do it themselves. Split into url namespaces: server.company.com/john/, server.company.com/kate/, etc. Pro: They now can make a single welcome page at root with any additional info (if they need?) Con: Each server would need to know their namespace string constant, and hrefs like / whould need patching. Split into ports: server.company.com:8080, server.company.com:8081, etc. and make a single :80 welcome page. Pro: They still can make a single welcome page at :80 Con: ??? I would like to know more pros and cons for 2 and 3 solution.

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  • How to learn PHP effectively?

    - by Goma
    A dozen of bad tutorials out there that teach you bad habits especially when we speak about PHP. I want to learn how to avoid the things that can lead me to develop inefficient web applications. I like to learn from videos but most videos I've found on the internet are provided by people who do not follow good practices. My second option is to learn from books but I did not find a good book for starters in PHP! It would be very helpful for me if you can tell me about your story in learning PHP, what are things that I should avoid? How to learn about PHP security from the beginning to avoid unlearn something later on?. Please provide links to books, websites that provide high quality video tutorials for PHP, and you tips for a good start!

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  • Too many heap subpools might break the upgrade

    - by Mike Dietrich
    Recently one of our new upcoming Oracle Database 11.2 reference customers did upgrade their production database - a huge EBS system - from Oracle 9.2.0.8 to Oracle Database 11.2.0.2. They've tested very well, we've optimized the upgrade process, the recompilation timings etc.  But once the live upgrade was done it did fail in the JAVA component piece with this error: begin if initjvmaux.startstep('CREATE_JAVA_SYSTEM') then * ORA-29553: classw in use: SYS.javax/mail/folder ORA-06512: at "SYS.INITJVMAUX", line 23 ORA-06512: at line 5 Support diagnosis was pretty quick - and refered to:Bug 10165223 - ORA-29553: class in use: sys.javax/mail/folder during database upgrade But how could this happen? Actually I don't know as we have used the same init.ora setup on test and production. The only difference: the prod system has more CPUs and RAM. Anyway, the bug names as workarounds to either decrease the SGA to less than 1GB or decrease the number of heap subpools to 1. Finally this query did help to diagnose the number of heap subpools: select count(distinct kghluidx) num_subpools from x$kghlu where kghlushrpool = 1; The result was 2 - so we did run the upgrade now with this parameter set: _kghdsidx_count=1 And finally it did work well. One sad thing:After the upgrade did fail Support did recommend to restore the whole database - which took an additional 3-4 hours. As the ORACLE SERVER component has been already upgraded successfully at the stage where the error did happen it would have been fine to go on with the manual upgrade and start catupgrd.sql script. It would have been detected that the ORACLE SERVER is upgraded already and just picked up the non-upgraded components. The good news:Finally I had one extra slide to add to our workshop presentation

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  • Android: Layouts and views or a single full screen custom view?

    - by futlib
    I'm developing an Android game, and I'm making it so that it can run on low end devices without GPU, so I'm using the 2D API. I have so far tried to use Android's mechanisms such as layouts and activities where possible, but I'm beginning to wonder if it's not easier to just create a single custom view (or one per activity) and do all the work there. Here's an example of how I currently do things: I'm using a layout to display the game's background as an image view and the square game area, which is a custom view, centered in the middle. What would you say? Should I continue to use layouts where possible or is it more common/reasonable to just use a large custom view? I'm thinking that this would probably also make it easier to port my code to other platforms.

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  • Quick Tip - Speed a Slow Restore from the Transaction Log

    - by KKline
    Here's a quick tip for you: During some restore operations on Microsoft SQL Server, the transaction log redo step might be taking an unusually long time. Depending somewhat on the version and edition of SQL Server you've installed, you may be able to increase performance by tinkering with the readahead performance for the redo operations. To do this, you should use the MAXTRANSFERSIZE parameter of the RESTORE statement. For example, if you set MAXTRANSFERSIZE=1048576, it'll use 1MB buffers. If you...(read more)

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  • Implementing Service Level Agreements in Enterprise Manager 12c for Oracle Packaged Applications

    - by Anand Akela
    Contributed by Eunjoo Lee, Product Manager, Oracle Enterprise Manager. Service Level Management, or SLM, is a key tool in the proactive management of any Oracle Packaged Application (e.g., E-Business Suite, Siebel, PeopleSoft, JD Edwards E1, Fusion Apps, etc.). The benefits of SLM are that administrators can utilize representative Application transactions, which are constantly and automatically running behind the scenes, to verify that all of the key application and technology components of an Application are available and performing to expectations. A single transaction can verify the availability and performance of the underlying Application Tech Stack in a much more efficient manner than by monitoring the same underlying targets individually. In this article, we’ll be demonstrating SLM using Siebel Applications, but the same tools and processes apply to any of the Package Applications mentioned above. In this demonstration, we will log into the Siebel Application, navigate to the Contacts View, update a contact phone record, and then log-out. This transaction exposes availability and performance metrics of multiple Siebel Servers, multiple Components and Component Groups, and the Siebel Database - in a single unified manner. We can then monitor and manage these transactions like any other target in EM 12c, including placing pro-active alerts on them if the transaction is either unavailable or is not performing to required levels. The first step in the SLM process is recording the Siebel transaction. The following screenwatch demonstrates how to record Siebel transaction using an EM tool called “OpenScript”. A completed recording is called a “Synthetic Transaction”. The second step in the SLM process is uploading the Synthetic Transaction into EM 12c, and creating Generic Service Tests. We can create a Generic Service Test to execute our synthetic transactions at regular intervals to evaluate the performance of various business flows. As these transactions are running periodically, it is possible to monitor the performance of the Siebel Application by evaluating the performance of the synthetic transactions. The process of creating a Generic Service Test is detailed in the next screenwatch. EM 12c provides a guided workflow for all of the key creation steps, including configuring the Service Test, uploading of the Synthetic Test, determining the frequency of the Service Test, establishing beacons, and selecting performance and usage metrics, just to name a few. The third and final step in the SLM process is the creation of Service Level Agreements (SLA). Service Level Agreements allow Administrators to utilize the previously created Service Tests to specify expected service levels for Application availability, performance, and usage. SLAs can be created for different time periods and for different Service Tests. This last screenwatch demonstrates the process of creating an SLA, as well as highlights the Dashboards and Reports that Administrators can use to monitor Service Test results. Hopefully, this article provides you with a good start point for creating Service Level Agreements for your E-Business Suite, Siebel, PeopleSoft, JD Edwards E1, or Fusion Applications. Enterprise Manager Cloud Control 12c, with the Application Management Suites, represents a quick and easy way to implement Service Level Management capabilities at customer sites. Stay Connected: Twitter |  Face book |  You Tube |  Linked in |  Google+ |  Newsletter

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  • Should we consider code language upon design?

    - by Codex73
    Summary This question aims to conclude if an applications usage will be a consideration when deciding upon development language. What factors if any could be considered upon language writing could be taken into context. Application Type: Web Question Of the following popular languages, when should we use one or the other? What factors if any could be considered upon language writing could be taken into context. Languages PHP Ruby Python My initial thought is that language shouldn't be considered as much as framework. Things to consider on framework are scalability, usage, load, portability, modularity and many more. Things to consider on Code Writing maybe cost, framework stability, community, etc.

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  • Should all, none, or some overriden methods call Super?

    - by JoJo
    When designing a class, how do you decide when all overridden methods should call super or when none of the overridden methods should call super? Also, is it considered bad practice if your code logic requires a mixture of supered and non-supered methods like the Javascript example below? ChildClass = new Class.create(ParentClass, { /** * @Override */ initialize: function($super) { $super(); this.foo = 99; }, /** * @Override */ methodOne: function($super) { $super(); this.foo++; }, /** * @Override */ methodTwo: function($super) { this.foo--; } }); After delving into the iPhone and Android SDKs, I noticed that super must be called on every overridden method, or else the program will crash because something wouldn't get initialized. When deriving from a template/delegate, none of the methods are supered (obviously). So what exactly are these "je ne sais quoi" qualities that determine whether a all, none, or some overriden methods should call super?

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  • Is good practice to optimize FPS even when it's above the lower limit to give illusion of movement?

    - by rraallvv
    I started over 50 FPS on the iPhone, but now I'm bellow 30 PFS, I've seen most iPhone games clamped to either 60 or 30 FPS, even when 24 or less would give the illusion of movement. I've concidered my limit to be a little bit over 15 FPS, in fact my physics simulation is updated at that rate (15.84 steps/s) as that is the lowest that still give fluid movement, a bit lower gives jerky motion. Is there a practical reason why to clamp FPS way above the lower limit? Update: The following image could help to clarify I can independently set the physic simulation step, frame rate, and simulation interval update. My concern is why should I clamp any of those to values greater than the minimum? For instance to conserve battery life I could just to choose the lower limits, but it seems that 60 or 30 FPS are the most used values.

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  • Using the @ in SQL Azure Connections

    - by BuckWoody
    The other day I was working with a client on an application they were changing to a hybrid architecture – some data on-premise and other data in SQL Azure and Windows Azure Blob storage. I had them make a couple of corrections - the first was that all communications to SQL Azure need to be encrypted. It’s a simple addition to the connection string, depending on the library you use. Which brought up another interesting point. They had been using something that looked like this, using the .NET provider: Server=tcp:[serverName].database.windows.net;Database=myDataBase; User ID=LoginName;Password=myPassword; Trusted_Connection=False;Encrypt=True; This includes most of the formatting needed for SQL Azure. It specifies TCP as the transport mechanism, the database name is included, Trusted_Connection is off, and encryption is on. But it needed one more change: Server=tcp:[serverName].database.windows.net;Database=myDataBase; User ID=[LoginName]@[serverName];Password=myPassword; Trusted_Connection=False;Encrypt=True; Notice the difference? It’s the User ID parameter. It includes the @ symbol and the name of the server – not the whole DNS name, just the server name itself. The developers were a bit surprised, since it had been working with the first format that just used the user name. Why did both work, and why is one better than the other? It has to do with the connection library you use. For most libraries, the user name is enough. But for some libraries (subject to change so I don’t list them here) the server name parameter isn’t sent in the way the load balancer understands, so you need to include the server name right in the login, so the system can parse it correctly. Keep in mind, the string limit for that is 128 characters – so take the @ symbol and the server name into consideration for user names. The user connection info is detailed here: http://msdn.microsoft.com/en-us/library/ee336268.aspx Upshot? Include the @servername on your connection string just to be safe. And plan for that extra space…  

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  • How to organize a Coding Dojo?

    - by Stephan
    Over on stack overflow it was asked how to organize a coding dojo (http://stackoverflow.com/questions/4338567/how-to-organize-a-coding-dojo-event). I believe that may have been the wrong forum... I wonder the same thing: how is a Codeing Dojo organized? What is the structure of a meeting? How would one pick Katas? What do you plan ahead of time? I am interested in any ideas on this as well as links to any resource that may be outlining this.

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  • Is nesting types considered bad practice?

    - by Rob Z
    As noted by the title, is nesting types (e.g. enumerated types or structures in a class) considered bad practice or not? When you run Code Analysis in Visual Studio it returns the following message which implies it is: Warning 34 CA1034 : Microsoft.Design : Do not nest type 'ClassName.StructueName'. Alternatively, change its accessibility so that it is not externally visible. However, when I follow the recommendation of the Code Analysis I find that there tend to be a lot of structures and enumerated types floating around in the application that might only apply to a single class or would only be used with that class. As such, would it be appropriate to nest the type sin that case, or is there a better way of doing it?

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  • Is the "One Description Table to rule them all" approch good?

    - by DavRob60
    Long ago, I worked (as a client) with a software which use a centralized table for it's codified element. Here, as far as I remember, how the table look like : Table_Name (PK) Field_Name (PK) Code (PK) Sort_Order Description So, instead of creating a table every time they need a codified field, they where just adding row in this table with the new Table_Name and Field_Name. I'm sometime tempted to use this pattern in some database I design, but I have resisted to this as from now, I think there's something wrong with this, but I cannot put the finger on it. It is just because you land with some of the structure logic within the Data or something else?

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  • High Availability for IaaS, PaaS and SaaS in the Cloud

    - by BuckWoody
    Outages, natural disasters and unforeseen events have proved that even in a distributed architecture, you need to plan for High Availability (HA). In this entry I'll explain a few considerations for HA within Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS) and Software-as-a-Service (SaaS). In a separate post I'll talk more about Disaster Recovery (DR), since each paradigm has a different way to handle that. Planning for HA in IaaS IaaS involves Virtual Machines - so in effect, an HA strategy here takes on many of the same characteristics as it would on-premises. The primary difference is that the vendor controls the hardware, so you need to verify what they do for things like local redundancy and so on from the hardware perspective. As far as what you can control and plan for, the primary factors fall into three areas: multiple instances, geographical dispersion and task-switching. In almost every cloud vendor I've studied, to ensure your application will be protected by any level of HA, you need to have at least two of the Instances (VM's) running. This makes sense, but you might assume that the vendor just takes care of that for you - they don't. If a single VM goes down (for whatever reason) then the access to it is lost. Depending on multiple factors, you might be able to recover the data, but you should assume that you can't. You should keep a sync to another location (perhaps the vendor's storage system in another geographic datacenter or to a local location) to ensure you can continue to serve your clients. You'll also need to host the same VM's in another geographical location. Everything from a vendor outage to a network path problem could prevent your users from reaching the system, so you need to have multiple locations to handle this. This means that you'll have to figure out how to manage state between the geo's. If the system goes down in the middle of a transaction, you need to figure out what part of the process the system was in, and then re-create or transfer that state to the second set of systems. If you didn't write the software yourself, this is non-trivial. You'll also need a manual or automatic process to detect the failure and re-route the traffic to your secondary location. You could flip a DNS entry (if your application can tolerate that) or invoke another process to alias the first system to the second, such as load-balancing and so on. There are many options, but all of them involve coding the state into the application layer. If you've simply moved a state-ful application to VM's, you may not be able to easily implement an HA solution. Planning for HA in PaaS Implementing HA in PaaS is a bit simpler, since it's built on the concept of stateless applications deployment. Once again, you need at least two copies of each element in the solution (web roles, worker roles, etc.) to remain available in a single datacenter. Also, you need to deploy the application again in a separate geo, but the advantage here is that you could work out a "shared storage" model such that state is auto-balanced across the world. In fact, you don't have to maintain a "DR" site, the alternate location can be live and serving clients, and only take on extra load if the other site is not available. In Windows Azure, you can use the Traffic Manager service top route the requests as a type of auto balancer. Even with these benefits, I recommend a second backup of storage in another geographic location. Storage is inexpensive; and that second copy can be used for not only HA but DR. Planning for HA in SaaS In Software-as-a-Service (such as Office 365, or Hadoop in Windows Azure) You have far less control over the HA solution, although you still maintain the responsibility to ensure you have it. Since each SaaS is different, check with the vendor on the solution for HA - and make sure you understand what they do and what you are responsible for. They may have no HA for that solution, or pin it to a particular geo, or perhaps they have a massive HA built in with automatic load balancing (which is often the case).   All of these options (with the exception of SaaS) involve higher costs for the design. Do not sacrifice reliability for cost - that will always cost you more in the end. Build in the redundancy and HA at the very outset of the project - if you try to tack it on later in the process the business will push back and potentially not implement HA. References: http://www.bing.com/search?q=windows+azure+High+Availability  (each type of implementation is different, so I'm routing you to a search on the topic - look for the "Patterns and Practices" results for the area in Azure you're interested in)

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  • Should all, none, or some overridden methods call Super?

    - by JoJo
    When designing a class, how do you decide when all overridden methods should call super or when none of the overridden methods should call super? Also, is it considered bad practice if your code logic requires a mixture of supered and non-supered methods like the Javascript example below? ChildClass = new Class.create(ParentClass, { /** * @Override */ initialize: function($super) { $super(); this.foo = 99; }, /** * @Override */ methodOne: function($super) { $super(); this.foo++; }, /** * @Override */ methodTwo: function($super) { this.foo--; } }); After delving into the iPhone and Android SDKs, I noticed that super must be called on every overridden method, or else the program will crash because something wouldn't get initialized. When deriving from a template/delegate, none of the methods are supered (obviously). So what exactly are these "je ne sais quoi" qualities that determine whether a all, none, or some overriden methods should call super?

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