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• Sparse virtual machine disk image resizing weirdness?

  - by Matt H

  I have a partitioned virtual machine disk image created by vmware. What I want to do is resize that by 10GB. The file size is showing as 64424509440. Or 60GB. So I ran this: dd if=/dev/zero of=./win7.img seek=146800640 count=0 It ran without errors and I can verify the new size is in fact 75161927680 bytes or 70GB. This is where it gets a little odd. I started the guest domain in xen which is a Windows 7 enterprise machine. What I was expecting to see in diskmgmt.msc is 2 partitions. 1 system partition at the start of around 100MB and near 60GB partition (which is C drive) followed by around 10GB of free space. Actually what I saw was a 70GB partition!?! That confused me... so I decided to run the Check Disk which when you set it on the C drive it asks you to reboot so it'll run on boot. So I did that and during the boot it ran the checks. It got all the way through stage 3 and didn't show any errors at all. Looked at the partitions in disk manager and now C drive has shrunk back to 60GB and there is no free space. What gives? Ok, I thought I'd try mounting it under Dom0 and examining it with fdisk. This is what I get when mounted sudo xl block-attach 0 tap:aio:/home/xen/vms/otoy_v1202-xen.img xvda w sudo fdisk -l /dev/xvda Disk /dev/xvda: 64.4 GB, 64424509440 bytes 255 heads, 63 sectors/track, 7832 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0x582dfc96 Device Boot Start End Blocks Id System /dev/xvda1 * 1 13 102400 7 HPFS/NTFS Partition 1 does not end on cylinder boundary. /dev/xvda2 13 7833 62810112 7 HPFS/NTFS Note the cylinder boundary comment. When I run sudo cfdisk /dev/xvda I get: FATAL ERROR: Bad primary partition 1: Partition ends in the final partial cylinder Press any key to exit cfdisk So I guess this is a bigger problem than first thought. How can I fix this? EDIT: Oops, the cylinder boundary thing is not a problem at all since disks have used LBA etc. So that threw me for a moment... still the problem exists... Now this output looks a little different. sudo sfdisk -uS -l /dev/xvda Disk /dev/xvda: 7832 cylinders, 255 heads, 63 sectors/track Units = sectors of 512 bytes, counting from 0 Device Boot Start End #sectors Id System /dev/xvda1 * 2048 206847 204800 7 HPFS/NTFS /dev/xvda2 206848 125827071 125620224 7 HPFS/NTFS /dev/xvda3 0 - 0 0 Empty /dev/xvda4 0 - 0 0 Empty BTW: I do have a backup of the image so if you help me mess it up that's ok. EDIT: sudo parted /dev/xvda print free Model: Xen Virtual Block Device (xvd) Disk /dev/xvda: 64.4GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 32.3kB 1049kB 1016kB Free Space 1 1049kB 106MB 105MB primary ntfs boot 2 106MB 64.4GB 64.3GB primary ntfs 64.4GB 64.4GB 1049kB Free Space Cool. Linux is showing free space is 10GB which is what I expect. The problem is windows isn't seeing this?

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• Oracle MAA Part 1: When One Size Does Not Fit All

  - by JoeMeeks

  The good news is that Oracle Maximum Availability Architecture (MAA) best practices combined with Oracle Database 12c (see video) introduce first-in-the-industry database capabilities that truly make unplanned outages and planned maintenance transparent to users. The trouble with such good news is that Oracle’s enthusiasm in evangelizing its latest innovations may leave some to wonder if we’ve lost sight of the fact that not all database applications are created equal. Afterall, many databases don’t have the business requirements for high availability and data protection that require all of Oracle’s ‘stuff’. For many real world applications, a controlled amount of downtime and/or data loss is OK if it saves money and effort. Well, not to worry. Oracle knows that enterprises need solutions that address the full continuum of requirements for data protection and availability. Oracle MAA accomplishes this by defining four HA service level tiers: BRONZE, SILVER, GOLD and PLATINUM. The figure below shows the progression in service levels provided by each tier. Each tier uses a different MAA reference architecture to deploy the optimal set of Oracle HA capabilities that reliably achieve a given service level (SLA) at the lowest cost.  Each tier includes all of the capabilities of the previous tier and builds upon the architecture to handle an expanded fault domain. Bronze is appropriate for databases where simple restart or restore from backup is ‘HA enough’. Bronze is based upon a single instance Oracle Database with MAA best practices that use the many capabilities for data protection and HA included with every Oracle Enterprise Edition license. Oracle-optimized backups using Oracle Recovery Manager (RMAN) provide data protection and are used to restore availability should an outage prevent the database from being able to restart. Silver provides an additional level of HA for databases that require minimal or zero downtime in the event of database instance or server failure as well as many types of planned maintenance. Silver adds clustering technology - either Oracle RAC or RAC One Node. RMAN provides database-optimized backups to protect data and restore availability should an outage prevent the cluster from being able to restart. Gold raises the game substantially for business critical applications that can’t accept vulnerability to single points-of-failure. Gold adds database-aware replication technologies, Active Data Guard and Oracle GoldenGate, which synchronize one or more replicas of the production database to provide real time data protection and availability. Database-aware replication greatly increases HA and data protection beyond what is possible with storage replication technologies. It also reduces cost while improving return on investment by actively utilizing all replicas at all times. Platinum introduces all of the sexy new Oracle Database 12c capabilities that Oracle staff will gush over with great enthusiasm. These capabilities include Application Continuity for reliable replay of in-flight transactions that masks outages from users; Active Data Guard Far Sync for zero data loss protection at any distance; new Oracle GoldenGate enhancements for zero downtime upgrades and migrations; and Global Data Services for automated service management and workload balancing in replicated database environments. Each of these technologies requires additional effort to implement. But they deliver substantial value for your most critical applications where downtime and data loss are not an option. The MAA reference architectures are inherently designed to address conflicting realities. On one hand, not every application has the same objectives for availability and data protection – the Not One Size Fits All title of this blog post. On the other hand, standard infrastructure is an operational requirement and a business necessity in order to reduce complexity and cost. MAA reference architectures address both realities by providing a standard infrastructure optimized for Oracle Database that enables you to dial-in the level of HA appropriate for different service level requirements. This makes it simple to move a database from one HA tier to the next should business requirements change, or from one hardware platform to another – whether it’s your favorite non-Oracle vendor or an Oracle Engineered System. Please stay tuned for additional blog posts in this series that dive into the details of each MAA reference architecture. Meanwhile, more information on Oracle HA solutions and the Maximum Availability Architecture can be found at: Oracle Maximum Availability Architecture - Webcast Maximize Availability with Oracle Database 12c - Technical White Paper

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• NHibernate and Stored Procedures in C#

  - by Jess Nickson

  I was recently trying and failing to set up NHibernate (v1.2) in an ASP.NET project. The aim was to execute a stored procedure and return the results, but it took several iterations for me to end up with a working solution. In this post I am simply trying to put the required code in one place, in the hope that the snippets may be useful in guiding someone else through the same process. As it is kind’ve the first time I have had to play with NHibernate, there is a good chance that this solution is sub-optimal and, as such, I am open to suggestions on how it could be improved! There are four code snippets that I required: The stored procedure that I wanted to execute The C# class representation of the results of the procedure The XML mapping file that allows NHibernate to map from C# to the procedure and back again The C# code used to run the stored procedure The Stored Procedure The procedure was designed to take a UserId and, from this, go and grab some profile data for that user. Simple, right? We just need to do a join first, because the user’s site ID (the one we have access to) is not the same as the user’s forum ID. CREATE PROCEDURE [dbo].[GetForumProfileDetails] ( @userId INT ) AS BEGIN SELECT Users.UserID, forumUsers.Twitter, forumUsers.Facebook, forumUsers.GooglePlus, forumUsers.LinkedIn, forumUsers.PublicEmailAddress FROM Users INNER JOIN Forum_Users forumUsers ON forumUsers.UserSiteID = Users.UserID WHERE Users.UserID = @userId END I’d like to make a shout out to Format SQL for its help with, well, formatting the above SQL!   The C# Class This is just the class representation of the results we expect to get from the stored procedure. NHibernate requires a virtual property for each column of data, and these properties must be called the same as the column headers. You will also need to ensure that there is a public or protected parameterless constructor. public class ForumProfile : IForumProfile { public virtual int UserID { get; set; } public virtual string Twitter { get; set; } public virtual string Facebook { get; set; } public virtual string GooglePlus { get; set; } public virtual string LinkedIn { get; set; } public virtual string PublicEmailAddress { get; set; } public ForumProfile() { } }   The NHibernate Mapping File This is the XML I wrote in order to make NHibernate a) aware of the stored procedure, and b) aware of the expected results of the procedure. <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" namespace="[namespace]" assembly="[assembly]"> <sql-query name="GetForumProfileDetails"> <return-scalar column="UserID" type="Int32"/> <return-scalar column="Twitter" type="String"/> <return-scalar column="Facebook" type="String"/> <return-scalar column="GooglePlus" type="String"/> <return-scalar column="LinkedIn" type="String"/> <return-scalar column="PublicEmailAddress" type="String"/> exec GetForumProfileDetails :UserID </sql-query> </hibernate-mapping>   Calling the Stored Procedure Finally, to bring it all together, the C# code that I used in order to execute the stored procedure! public IForumProfile GetForumUserProfile(IUser user) { return NHibernateHelper .GetCurrentSession() .GetNamedQuery("GetForumProfileDetails") .SetInt32("UserID", user.UserID) .SetResultTransformer( Transformers.AliasToBean(typeof (ForumProfile))) .UniqueResult<ForumProfile>(); } There are a number of ‘Set’ methods (i.e. SetInt32) that allow you specify values for any parameters in the procedure. The AliasToBean method is then required to map the returned scalars (as specified in the XML) to the correct C# class.

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• Efficiently separating Read/Compute/Write steps for concurrent processing of entities in Entity/Component systems

  - by TravisG

  Setup I have an entity-component architecture where Entities can have a set of attributes (which are pure data with no behavior) and there exist systems that run the entity logic which act on that data. Essentially, in somewhat pseudo-code: Entity { id; map<id_type, Attribute> attributes; } System { update(); vector<Entity> entities; } A system that just moves along all entities at a constant rate might be MovementSystem extends System { update() { for each entity in entities position = entity.attributes["position"]; position += vec3(1,1,1); } } Essentially, I'm trying to parallelise update() as efficiently as possible. This can be done by running entire systems in parallel, or by giving each update() of one system a couple of components so different threads can execute the update of the same system, but for a different subset of entities registered with that system. Problem In reality, these systems sometimes require that entities interact(/read/write data from/to) each other, sometimes within the same system (e.g. an AI system that reads state from other entities surrounding the current processed entity), but sometimes between different systems that depend on each other (i.e. a movement system that requires data from a system that processes user input). Now, when trying to parallelize the update phases of entity/component systems, the phases in which data (components/attributes) from Entities are read and used to compute something, and the phase where the modified data is written back to entities need to be separated in order to avoid data races. Otherwise the only way (not taking into account just "critical section"ing everything) to avoid them is to serialize parts of the update process that depend on other parts. This seems ugly. To me it would seem more elegant to be able to (ideally) have all processing running in parallel, where a system may read data from all entities as it wishes, but doesn't write modifications to that data back until some later point. The fact that this is even possible is based on the assumption that modification write-backs are usually very small in complexity, and don't require much performance, whereas computations are very expensive (relatively). So the overhead added by a delayed-write phase might be evened out by more efficient updating of entities (by having threads work more % of the time instead of waiting). A concrete example of this might be a system that updates physics. The system needs to both read and write a lot of data to and from entities. Optimally, there would be a system in place where all available threads update a subset of all entities registered with the physics system. In the case of the physics system this isn't trivially possible because of race conditions. So without a workaround, we would have to find other systems to run in parallel (which don't modify the same data as the physics system), other wise the remaining threads are waiting and wasting time. However, that has disadvantages Practically, the L3 cache is pretty much always better utilized when updating a large system with multiple threads, as opposed to multiple systems at once, which all act on different sets of data. Finding and assembling other systems to run in parallel can be extremely time consuming to design well enough to optimize performance. Sometimes, it might even not be possible at all because a system just depends on data that is touched by all other systems. Solution? In my thinking, a possible solution would be a system where reading/updating and writing of data is separated, so that in one expensive phase, systems only read data and compute what they need to compute, and then in a separate, performance-wise cheap, write phase, attributes of entities that needed to be modified are finally written back to the entities. The Question How might such a system be implemented to achieve optimal performance, as well as making programmer life easier? What are the implementation details of such a system and what might have to be changed in the existing EC-architecture to accommodate this solution?

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• Get Ready for Anytime, Anywhere Engagement

  - by Christie Flanagan

  Normal 0 false false false EN-US X-NONE X-NONE /* 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-top:0in; mso-para-margin-right:0in; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0in; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Are you ready for 2015?  According to IDC, 2015 is the year when more users are projected to access the internet using mobile devices than with PC’s or other wired devices.  It’s no doubt that mobile devices are a critical means of communication today, and are on track to become increasingly more important in the coming years. However, device formats are so varied that delivering a mobile web experience that will engage site visitors and enhance your brand can be a daunting task. Solutions that empower organizations to easily extend their web presence to the mobile channel, while saving significant time and effort in managing mobile sites, are now essential in our ever connected mobile world. So what are some of the things organizations should look for in such a solution? Mobile device form factors, networks, protocols, and browsers vary widely, and reformatting web content for thousands of different device and software combinations is a prohibitive task. An effective mobile solution can make this process seamless by automatically formatting designated web content for mobile delivery.  By automatically detecting a site visitor’s device configuration, the selected web content can be sized and formatted for optimal display on that particular device. This can save tremendous time involved in building, formatting, and maintaining individual websites or mobile applications for different mobile devices. It’s not enough to simply support the thousands of different mobile device types that are out there. It’s also critical to make it easy for marketers and other business users to manage mobile sites and mobile content. Those responsible for maintaining an organization’s web and mobile experiences need the ability to edit content using rich text editor tools and then preview that content directly in the context of the mobile website and the traditional website, ideally from the same business user interface. Powerful capabilities such as these make managing the web experience for mobile devices easy, even with frequently changing content, across a multitude of different devices. This saves tremendous time involved in building, formatting, and maintaining individual websites or mobile applications for different mobile devices. When content or business needs change, the business user needs only to change site content once, and it is seamlessly deployed to the web and all mobile channels.Geo-location is another critical input to making the online experience engaging and relevant for web visitors who are increasingly mobile. A mobile solution should enable use of device GPS data to deliver location-based content and services to mobile website visitors. Organizations can provide mobile site visitors with location-sensitive search results, location-based offers and recommendations, integration of maps and directions into site content, and much more – all critical for meeting the needs of those on the go.To hear more about how mobile is changing the game, check out our recent webcast with Ted Schadler, Vice President, Principal Analyst, Forrester, where he discussed why mobile is the new face of engagement, or learn more about how to extend your web presence to the mobile channel with Oracle WebCenter Sites and Oracle WebCenter Sites Mobility Server.

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• ARTS Reference Model for Retail

  - by Sanjeev Sharma

  Consider a hypothetical scenario where you have been tasked to set up retail operations for a electronic goods or daily consumables or a luxury brand etc. It is very likely you will be faced with the following questions: What are the essential business capabilities that you must have in place?  What are the essential business activities under-pinning each of the business capabilities, identified in Step 1? What are the set of steps that you need to perform to execute each of the business activities, identified in Step 2? Answers to the above will drive your investments in software and hardware to enable the core retail operations. More importantly, the choices you make in responding to the above questions will several implications in the short-run and in the long-run. In the short-term, you will incur the time and cost of defining your technology requirements, procuring the software/hardware components and getting them up and running. In the long-term, as you grow in operations organically or through M&A, partnerships and franchiser business models  you will invariably need to make more technology investments to manage the greater complexity (scale and scope) of business operations.  "As new software applications, such as time & attendance, labor scheduling, and POS transactions, just to mention a few, are introduced into the store environment, it takes a disproportionate amount of time and effort to integrate them with existing store applications. These integration projects can add up to 50 percent to the time needed to implement a new software application and contribute significantly to the cost of the overall project, particularly if a systems integrator is called in. This has been the reality that all retailers have had to live with over the last two decades. The effect of the environment has not only been to increase costs, but also to limit retailers' ability to implement change and the speed with which they can do so." (excerpt taken from here) Now, one would think a lot of retailers would have already gone through the pain of finding answers to these questions, so why re-invent the wheel? Precisely so, a major effort began almost 17 years ago in the retail industry to make it less expensive and less difficult to deploy new technology in stores and at the retail enterprise level. This effort is called the Association for Retail Technology Standards (ARTS). Without standards such as those defined by ARTS, you would very likely end up experiencing the following: Increased Time and Cost due to resource wastage arising from re-inventing the wheel i.e. re-creating vanilla processes from scratch, and incurring, otherwise avoidable, mistakes and errors by ignoring experience of others Sub-optimal Process Efficiency due to narrow, isolated view of processes thereby ignoring process inter-dependencies i.e. optimizing parts but not the whole, and resulting in lack of transparency and inter-departmental finger-pointing Embracing ARTS standards as a blue-print for establishing or managing or streamlining your retail operations can benefit you in the following ways: Improved Time-to-Market from parity with industry best-practice processes e.g. ARTS, thus avoiding “reinventing the wheel” for common retail processes and focusing more on customizing processes for differentiations, and lowering integration complexity and risk with a standardized vocabulary for exchange between internal and external i.e. partner systems Lower Operating Costs by embracing the ARTS enterprise-wide process reference model for developing and streamlining retail operations holistically instead of a narrow, silo-ed view, and  procuring IT systems in compliance with ARTS thus avoiding IT budget marginalization While parity with industry standards such as ARTS business process model by itself does not create a differentiation, it does however provide a higher starting point for bridging the strategy-execution gap in setting up and improving retail operations.

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• What is a good design pattern / lib for iOS 5 to synchronize with a web service?

  - by Junto

  We are developing an iOS application that needs to synchronize with a remote server using web services. The existing web services have an "operations" style rather than REST (implemented in WCF but exposing JSON HTTP endpoints). We are unsure of how to structure the web services to best fit with iOS and would love some advice. We are also interested in how to manage the synchronization process within iOS. Without going into detailed specifics, the application allows the user to estimate repair costs at a remote site. These costs are broken down by room and item. If the user has an internet connection this data can be sent back to the server. Multiple photographs can be taken of each item, but they will be held in a separate queue, which sends when the connection is optimal (ideally wifi). Our backend application controls the unique ids for each room and item. Thus, each time we send these costs to the server, the server echoes the central database ids back, thus, that they can be synchronized in the mobile app. I have simplified this a little, since the operations contract is actually much larger, but I just want to illustrate the basic requirements without complicating matters. Firstly, the web service architecture: We currently have two operations: GetCosts and UpdateCosts. My assumption is that if we used a strict REST architecture we would need to break our single web service operations into multiple smaller services. This would make the services much more chatty and we would also have to guarantee a delivery order from the app. For example, we need to make sure that containing rooms are added before the item. Although this seems much more RESTful, our perception is that these extra calls are expensive connections (security checks, database calls, etc). Does the type of web api (operation over service focus) determine chunky vs chatty? Since this is mobile (3G), are we better handling lots of smaller messages, or a few large ones? Secondly, the iOS side. What is the current advice on how to manage data synchronization within the iOS (5) app itself. We need multiple queues and we need to guarantee delivery order in each queue (and technically, ordering between queues). The server needs to control unique ids and other properties and echo them back to the application. The application then needs to update an internal database and when re-updating, make sure the correct ids are available in the update message (essentially multiple inserts and updates in one call). Our backend has a ton of business logic operating on these cost estimates. We don't want any of this in the app itself. Currently the iOS app sends the cost data, and then the server echoes that data back with populated ids (and other data). The existing cost data is deleted and the echoed response data is added to the client database on the device. This is causing us problems, because any photos might not have been sent, but the original entity tree has been removed and replaced. Obviously updating the costs tree rather than replacing it would remove this problem, but I'm not sure if there are any nice xcode libraries out there to do such things. I welcome any advice you might have.

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• Oracle at ARM TechCon

  - by Tori Wieldt

  ARM TechCon is a technical conference for hardware and software engineers, Oct. 30-Nov 1 in Santa Clara, California. Days two and three of the conference will be geared towards systems designers and software developers, those interested in building ARM processor-based modules, boards, and systems. It will cover all of the hardware and software, tools, ranging from low-power design, networking and connectivity, open source software, and security. Oracle is a sponsor of ARM TechCon, and will present three Java sessions and a hands-on-lab:  "Do You Like Coffee with Your Dessert? Java and the Raspberry Pi" - The Raspberry Pi, an ARM-powered single board computer running a full Linux distro off an SD card has caused a huge wave of interest among developers. This session looks at how Java can be used on a device such as this. Using Java SE for embedded devices and a port of JavaFX, the presentation includes a variety of demonstrations of what the Raspberry Pi is capable of. The Raspberry Pi also provides GPIO line access, and the session covers how this can be used from Java applications. Prepare to be amazed at what this tiny board can do. (Angela Caicedo, Java Evangelist) "Modernizing the Explosion of Advanced Microcontrollers with Embedded Java" - This session explains why Oracle Java ME Embedded is the right choice for building small, connected, and intelligent embedded solutions, such as industrial control applications, smart sensing, wireless connectivity, e-health, or general machine-to-machine (M2M) functionality---extending your business to new areas, driving efficiency, and reducing cost. The new Oracle Java ME Embedded product brings the benefits of Java technology to microcontroller platforms. It is a full-featured, complete, compliant software runtime with value-add features targeted to the embedded space and has the ability to interface with additional hardware components, remote manageability, and over-the-air software updates. It is accompanied by a feature-rich set of tools free of charge. (Fareed Suliman, Java Product Manager) "Embedded Java in Smart Energy and Healthcare" - This session covers embedded Java products and technologies that enable smart and connect devices in the Smart Energy and Healthcare/Medical industries. (speaker Kevin Lee) "Java SE Embedded Development on ARM Made Easy" - This Hands-on Lab aims to show that developers already familiar with the Java develop/debug/deploy lifecycle can apply those same skills to develop Java applications, using Java SE Embedded, on embedded devices. (speaker Jim Connors) In the Oracle booth #603, you can see the following demos: Industry Solutions with JavaThis exhibit consists of a number of industry solutions and how they can be powered by Java technology deployed on embedded systems.  Examples in consumer devices, home gateways, mobile health, smart energy, industrial control, and tablets all powered by applications running on the Java platform are shown.  Some of the solutions demonstrate the ability of Java to connect intelligent devices at the edge of the network to the datacenter or the cloud as a total end-to-end platform.Java in M2M with QualcommThis station will exhibit a new M2M solutions platform co-developed by Oracle and Qualcomm that enables wireless communications for embedded smart devices powered by Java, and share the types of industry solutions that are possible.  In addition, a new platform for wearable devices based on the ARM Cortex M3 platform is exhibited.Why Java for Embedded?Demonstration platforms will show how traditional development environments, tools, and Java programming skills can be used to create applications for embedded devices.  The advantages that Java provides because of  the runtime's abstraction of software from hardware, modularity and scalability, security, and application portability and manageability are shared with attendees. Drop by and see why Java is an optimal applications platform for embedded systems.

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• Consumer Oriented Search In Oracle Endeca Information Discovery - Part 2

  - by Bob Zurek

  As discussed in my last blog posting on this topic, Information Discovery, a core capability of the Oracle Endeca Information Discovery solution enables businesses to search, discover and navigate through a wide variety of big data including structured, unstructured and semi-structured data. With search as a core advanced capabilities of our product it is important to understand some of the key differences and capabilities in the underlying data store of Oracle Endeca Information Discovery and that is our Endeca Server. In the last post on this subject, we talked about Exploratory Search capabilities along with support for cascading relevance. Additional search capabilities in the Endeca Server, which differentiate from simple keyword based "search boxes" in other Information Discovery products also include: The Endeca Server Supports Set Search.  The Endeca Server is organized around set retrieval, which means that it looks at groups of results (all the documents that match a search), as well as the relationship of each individual result to the set. Other approaches only compute the relevance of a document by comparing the document to the search query – not by comparing the document to all the others. For example, a search for “U.S.” in another approach might match to the title of a document and get a high ranking. But what if it were a collection of government documents in which “U.S.” appeared in many titles, making that clue less meaningful? A set analysis would reveal this and be used to adjust relevance accordingly. The Endeca Server Supports Second-Order Relvance. Unlike simple search interfaces in traditional BI tools, which provide limited relevance ranking, such as a list of results based on key word matching, Endeca enables users to determine the most salient terms to divide up the result. Determining this second-order relevance is the key to providing effective guidance. Support for Queries and Filters. Search is the most common query type, but hardly complete, and users need to express a wide range of queries. Oracle Endeca Information Discovery also includes navigation, interactive visualizations, analytics, range filters, geospatial filters, and other query types that are more commonly associated with BI tools. Unlike other approaches, these queries operate across structured, semi-structured and unstructured content stored in the Endeca Server. Furthermore, this set is easily extensible because the core engine allows for pluggable features to be added. Like a search engine, queries are answered with a results list, ranked to put the most likely matches first. Unlike “black box” relevance solutions, which generalize one strategy for everyone, we believe that optimal relevance strategies vary across domains. Therefore, it provides line-of-business owners with a set of relevance modules that let them tune the best results based on their content. The Endeca Server query result sets are summarized, which gives users guidance on how to refine and explore further. Summaries include Guided Navigation® (a form of faceted search), maps, charts, graphs, tag clouds, concept clusters, and clarification dialogs. Users don’t explicitly ask for these summaries; Oracle Endeca Information Discovery analytic applications provide the right ones, based on configurable controls and rules. For example, the analytic application might guide a procurement agent filtering for in-stock parts by visualizing the results on a map and calculating their average fulfillment time. Furthermore, the user can interact with summaries and filters without resorting to writing complex SQL queries. The user can simply just click to add filters. Within Oracle Endeca Information Discovery, all parts of the summaries are clickable and searchable. We are living in a search driven society where business users really seem to enjoy entering information into a search box. We do this everyday as consumers and therefore, we have gotten used to looking for that box. However, the key to getting the right results is to guide that user in a way that provides additional Discovery, beyond what they may have anticipated. This is why these important and advanced features of search inside the Endeca Server have been so important. They have helped to guide our great customers to success. 

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• Multidimensional multiple-choice knapsack problem: find a feasible solution

  - by Onheiron

  My assignment is to use local search heuristics to solve the Multidimensional multiple-choice knapsack problem, but to do so I first need to find a feasible solution to start with. Here is an example problem with what I tried so far. Problem R1 R2 R3 RESOUCES : 8 8 8 GROUPS: G1: 11.0 3 2 2 12.0 1 1 3 G2: 20.0 1 1 3 5.0 2 3 2 G3: 10.0 2 2 3 30.0 1 1 3 Sorting strategies To find a starting feasible solution for my local search I decided to ignore maximization of gains and just try to fit the resources requirements. I decided to sort the choices (strategies) in each group by comparing their "distance" from the multidimensional space origin, thus calculating SQRT(R1^2 + R2^2 + ... + RN^2). I felt like this was a keen solution as it somehow privileged those choices with resouce usages closer to each other (e.g. R1:2 R2:2 R3:2 < R1:1 R2:2 R3:3) even if the total sum is the same. Doing so and selecting the best choice from each group proved sufficent to find a feasible solution for many[30] different benchmark problems, but of course I knew it was just luck. So I came up with the problem presented above which sorts like this: R1 R2 R3 RESOUCES : 8 8 8 GROUPS: G1: 12.0 1 1 3 < select this 11.0 3 2 2 G2: 20.0 1 1 3 < select this 5.0 2 3 2 G3: 30.0 1 1 3 < select this 10.0 2 2 3 And it is not feasible because the resources consmption is R1:3, R2:3, R3:9. The easy solution is to pick one of the second best choices in group 1 or 2, so I'll need some kind of iteration (local search[?]) to find the starting feasible solution for my local search solution. Here are the options I came up with Option 1: iterate choices I tried to find a way to iterate all the choices with a specific order, something like G1 G2 G3 1 1 1 2 1 1 1 2 1 1 1 2 2 2 1 ... believeng that feasible solutions won't be that far away from the unfeasible one I start with and thus the number of iterations will keep quite low. Does this make any sense? If yes, how can I iterate the choices (grouped combinations) of each group keeping "as near as possibile" to the previous iteration? Option 2: Change the comparation term I tried to think how to find a better variable to sort the choices on. I thought at a measure of how "precious" a resource is based on supply and demand, so that an higer demand of a more precious resource will push you down the list, but this didn't help at all. Also I thought there probably isn't gonna be such a comparsion variable which assures me a feasible solution at first strike. I there such a variable? If not, is there a better sorting criteria anyways? Option 3: implement any known sub-optimal fast solving algorithm Unfortunately I could not find any of such algorithms online. Any suggestion?

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• MySQL Server 5.6 default my.cnf and my.ini

  - by user12626240

  We've introduced a default my.cnf / my.ini file for MySQL Server that you can now see in the 5.6.8 release candidate: # For advice on how to change settings please see # http://dev.mysql.com/doc/refman/5.6/en/server-configuration-defaults.html [mysqld] # Remove leading # and set to the amount of RAM for the most important data # cache in MySQL. Start at 70% of total RAM for dedicated server, else 10%. # innodb_buffer_pool_size = 128M   # Remove leading # to turn on a very important data integrity option: logging # changes to the binary log between backups. # log_bin   # These are commonly set, remove the # and set as required. # basedir = ..... # datadir = ..... # port = ..... # socket = ..... # server_id = .....   # Remove leading # to set options mainly useful for reporting servers. # The server defaults are faster for transactions and fast SELECTs. # Adjust sizes as needed, experiment to find the optimal values. # join_buffer_size = 128M # sort_buffer_size = 2M # read_rnd_buffer_size = 2M   sql_mode=NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES    There is also a template file called my-default.cnf or my-default.ini that has these lines near the start: # *** DO NOT EDIT THIS FILE. It's a template which will be copied to the # *** default location during install, and will be replaced if you # *** upgrade to a newer version of MySQL.   On Linux systems, the mysql_install_db command will copy the template file to the final location, where the server will read and use the file, removing the extra three lines. On Windows, the installer will create extra settings based on the answers you gave during installation. Neither will overwrite an existing my.cnf or my.ini file. The only initially active setting here is to change the value of  sql_mode from the server default of NO_ENGINE_SUBSTITUTION to NO_ENGINE_SUBSTITUTION,STRICT_TRANS_TABLES. This strict mode changes warnings for some non-standard behaviour into errors. This can cause applications which rely on the non-standard things, like dates that aren't valid, to lose data. If we had just changed the server default, the new setting would affect all servers that lack an explicit sql_mode setting, including those where strict mode is harmful. So we did it in the default file instead because that will only affect new server installations. You should expect that in our next version after 5.6, the server default will include STRICT_TRANS_TABLES. Our Windows installer and some of our connectors already use STRICT_TRANS_TABLES by default. Strict has been our preferred setting for many years and it is good to see some development platforms are using it. If you need the old behaviour, just remove the STRICT_TRANS_TABLES setting. If you do this, please also ask your application provider to make it unnecessary. They can do that by setting the session sql_mode setting in their own connections, so the rest of the applications using the server don't have to have an undesirable default. We've kept this file as small as possible because we found that our old files were too big and confused people. We've also now removed the old my-huge and related example files. One key part of this is the link to the documentation, where we will provide an introduction to some key settings. We'd like to hear your feedback on settings that will benefit most users or are most important to call out for existing users. Please do that by commenting here or if you prefer by adding comments to this bug report.

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• Rethinking Oracle Optimizer Statistics for P6 Part 2

  - by Brian Diehl

  In the previous post (Part 1), I tried to draw some key insights about the relationship between P6 and Oracle Optimizer Statistics.  The first is that average cardinality has the greatest impact on query optimization and that the particular queries generated by P6 are more likely to use this average during calculations. The second is that these are statistics that are unlikely to change greatly over the life of the application. Ultimately, our goal is to get the best query optimization possible.  Or is it? Stability No application administrator wants to get the call at 9am that their application users cannot get there work done because everything is running slow. This is a possibility with a regularly scheduled nightly collection of statistics. It may not just be slow performance, but a complete loss of service because one or more queries are optimized poorly. Ideally, this should not be the case. The database optimizer should make better decisions with more up-to-date data. Better statistics may give incremental performance benefit. However, this benefit must be balanced against the potential cost of system down time.  It is stability that we ultimately desire and not absolute optimal performance. We do want the benefit from more accurate statistics and better query plans, but not at the risk of an unusable system. As a result, I've developed the following methodology around managing database statistics for the P6 database.  1. No Automatic Re-Gathering - The daily, weekly, or other interval of statistic gathering is unlikely to be beneficial. Quite the opposite. It is more likely to cause problems. 2. Smart Re-Gathering - The time to collect statistics is when things have changed significantly. For a new installation of P6, this is happening more often because the data is growing from a few rows to thousands and more. But for a mature system, the data is not changing significantly from week-to-week. There are times to collect statistics: New releases of the application Changes in the underlying hardware or software versions (ex. new Oracle RDBMS version) When additional user groups are added. The new groups may use the software in significantly different ways. After significant changes in the data. This may be monthly, quarterly or yearly.  3. Always Test - If you take away one thing from this post, it would be to always have a plan to test after changing statistics. In reality, statistics can be collected as often as you desire provided there are tests in place to verify that performance is the same or better. These might be automated tests or simply a manual script of application functions. 4. Have a Way Out - Never change the statistics without a way to return to the previous set. Think of the statistics as one part of the overall application code that also includes the source code--both application and RDBMS. It would be foolish to change to the new code without a way to get back to the previous version. In the final post, I will talk about the actual script I created for P6 PMDB and possible future direction for managing query performance. 

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• return the result of a query and the total number of rows in a single function

  - by csotelo

  This is a question as might be focused on working in the best way, if there are other alternatives or is the only way: Using Codeigniter ... I have the typical 2 functions of list records and show total number of records (using the page as an alternative). The problem is that they are rather large. Sample 2 functions in my model: count Rows: function get_all_count() { $this->db->select('u.id_user'); $this->db->from('user u'); if($this->session->userdata('detail') != '1') { $this->db->join('management m', 'm.id_user = u.id_user', 'inner'); $this->db->where('id_detail', $this->session->userdata('detail')); if($this->session->userdata('management') === '1') { $this->db->or_where('detail', 1); } else { $this->db->where("id_profile IN ( SELECT e2.id_profile FROM profile e, profile e2, profile_path p, profile_path p2 WHERE e.id_profile = " . $this->session->userdata('profile') . " AND p2.id_profile = e.id_profile AND p.path LIKE(CONCAT(p2.path,'%')) AND e2.id_profile = p.id_profile )", NULL, FALSE); $this->db->where('MD5(u.id_user) <>', $this->session->userdata('id_user')); } } $this->db->where('u.id_user <>', 1); $this->db->where('flag <>', 3); $query = $this->db->get(); return $query->num_rows(); } results per page function get_all($limit, $offset, $sort = '') { $this->db->select('u.id_user, user, email, flag'); $this->db->from('user u'); if($this->session->userdata('detail') != '1') { $this->db->join('management m', 'm.id_user = u.id_user', 'inner'); $this->db->where('id_detail', $this->session->userdata('detail')); if($this->session->userdata('management') === '1') { $this->db->or_where('detail', 1); } else { $this->db->where("id_profile IN ( SELECT e2.id_profile FROM profile e, profile e2, profile_path p, profile_path p2 WHERE e.id_profile = " . $this->session->userdata('profile') . " AND p2.id_profile = e.id_profile AND p.path LIKE(CONCAT(p2.path,'%')) AND e2.id_profile = p.id_profile )", NULL, FALSE); $this->db->where('MD5(u.id_user) <>', $this->session->userdata('id_user')); } } $this->db->where('u.id_user <>', 1); $this->db->where('flag <>', 3); if($sort) $this->db->order_by($sort); $this->db->limit($limit, $offset); $query = $this->db->get(); return $query->result(); } You see, I repeat the most of the functions, the difference is that only the number of fields and management pages. I wonder if there is any alternative to get as much results as the query in a single function. I have seen many tutorials, and all create 2 functions: one to count and another to show results ... Will there be more optimal?

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• Writing a method to 'transform' an immutable object: how should I approach this?

  - by Prog

  (While this question has to do with a concrete coding dilemma, it's mostly about what's the best way to design a function.) I'm writing a method that should take two Color objects, and gradually transform the first Color into the second one, creating an animation. The method will be in a utility class. My problem is that Color is an immutable object. That means that I can't do color.setRGB or color.setBlue inside a loop in the method. What I can do, is instantiate a new Color and return it from the method. But then I won't be able to gradually change the color. So I thought of three possible solutions: 1- The client code includes the method call inside a loop. For example: int duration = 1500; // duration of the animation in milliseconds int steps = 20; // how many 'cycles' the animation will take for(int i=0; i<steps; i++) color = transformColor(color, targetColor, duration, steps); And the method would look like this: Color transformColor(Color original, Color target, int duration, int steps){ int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted return new Color(newRed, newGreen, newBlue); } The disadvantage of this approach is that the client code has to "do part of the method's job" and include a for loop. The method doesn't do it's work entirely on it's own, which I don't like. 2- Make a mutable Color subclass with methods such as setRed, and pass objects of this class into transformColor. Then it could look something like this: void transformColor(MutableColor original, Color target, int duration){ final int STEPS = 20; int redDiff = target.getRed() - original.getRed(); int redAddition = redDiff / steps; int newRed = original.getRed() + redAddition; // same for green and blue .. for(int i=0; i<STEPS; i++){ original.setRed(original.getRed() + redAddition); // same for green and blue .. Thread.sleep(duration / STEPS); // exception handling omitted } } Then the calling code would usually look something like this: // The method will usually transform colors of JComponents JComponent someComponent = ... ; // setting the Color in JComponent to be a MutableColor Color mutableColor = new MutableColor(someComponent.getForeground()); someComponent.setForeground(mutableColor); // later, transforming the Color in the JComponent transformColor((MutableColor)someComponent.getForeground(), new Color(200,100,150), 2000); The disadvantage is - the need to create a new class MutableColor, and also the need to do casting. 3- Pass into the method the actual mutable object that holds the color. Then the method could do object.setColor or similar every iteration of the loop. Two disadvantages: A- Not so elegant. Passing in the object that holds the color just to transform the color feels unnatural. B- While most of the time this method will be used to transform colors inside JComponent objects, other kinds of objects may have colors too. So the method would need to be overloaded to receive other types, or receive Objects and have instanceof checks inside.. Not optimal. Right now I think I like solution #2 the most, than solution #1 and solution #3 the least. However I'd like to hear your opinions and suggestions regarding this.

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• How do I deploy building blocks (quick parts) for Microsoft Outlook 2007?

  - by now

  I want to deploy some building blocks for Microsoft Outlook 2007. Microsoft has put up a poor solution at http://office.microsoft.com/en-us/outlook/HA102086531033.aspx#4 that asks you to save a template. That solution would require you to distribute that template to all the clients. An optimal solution would allow you to put the template containing the building blocks somewhere on the network and simply use the ”Workgroup building blocks path” group policy setting for shared paths in Microsoft Office 2007. Sadly, Outlook doesn’t respect that policy. Also, the described solution mentioned in the article above doesn’t work. Step 4 requests you to save the template as a Word Template after first asking you to save it as an Outlook Template. It seems that they copy&pasted the steps from the Word article and forgot to check whether it worked (and adjust the steps accordingly). Anyway, does anyone have any suggestions for how to distribute the building blocks without distributing NormalEmail.dotm (which will overwrite the clients’ own building blocks each time it is updated). Thanks!

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• Selectively suppress XML Code Comments in C#?

  - by Mike Post

  We deliver a number of assemblies to external customers, but not all of the public APIs are officially supported. For example, due to less than optimal design choices sometimes a type must be publicly exposed from an assembly for the rest of our code to work, but we don't want customers to use that type. One part of communicating the lack of support is not provide any intellisense in the form of XML comments. Is there a way to selectively suppress XML comments? I'm looking for something other than ignoring warning 1591 since it's a long term maintenance issue. Example: I have an assembly with public classes A and B. A is officially supported and should have XML documentation. B is not intended for external use and should not be documented. I could turn on XML documentation and then suppress warning 1591. But when I later add the officially supported class C, I want the compiler to tell me that I've screwed up and failed to add the XML documentation. This wouldn't occur if I had suppressed 1591 at the project level. I suppose I could #pragma across entire classes, but it seems like there should be a better way to do this.

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• how to tackle this combinatorial algorithm problem

  - by Andrew Bullock

  I have N people who must each take T exams. Each exam takes "some" time, e.g. 30 min (no such thing as finishing early). Exams must be performed in front of an examiner. I need to schedule each person to take each exam in front of an examiner within an overall time period, using the minimum number of examiners for the minimum amount of time (i.e. no examiners idle) There are the following restrictions: No person can be in 2 places at once each person must take each exam once noone should be examined by the same examiner twice I realise that an optimal solution is probably NP-Complete, and that I'm probably best off using a genetic algorithm to obtain a best estimate (similar to this? http://stackoverflow.com/questions/184195/seating-plan-software-recommendations-does-such-a-beast-even-exist). I'm comfortable with how genetic algorithms work, what i'm struggling with is how to model the problem programatically such that i CAN manipulate the parameters genetically.. If each exam took the same amount of time, then i'd divide the time period up into these lengths, and simply create a matrix of time slots vs examiners and drop the candidates in. However because the times of each test are not necessarily the same, i'm a bit lost on how to approach this. currently im doing this: make a list of all "tests" which need to take place, between every candidate and exam start with as many examiners as there are tests repeatedly loop over all examiners, for each one: find an unscheduled test which is eligible for the examiner (based on the restrictions) continue until all tests that can be scheduled, are if there are any unscheduled tests, increment the number of examiners and start again. i'm looking for better suggestions on how to approach this, as it feels rather crude currently.

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• File path for J2ME FileConnection?

  - by Kilnr

  Hi, I'm writing a MIDlet which needs to write file. I'm using FileConnection from JSR-75 to accomplish this. The intention is to have this MIDlet runnning on as much devices as possible (all MIDP 2.0 devices with JSR-75 support, ideally). On several emulators and an HTC Touch Pro2, I can perfectly use the following code to get the root of the filesystem: Enumeration drives = FileSystemRegistry.listRoots(); String root = (String) drives.nextElement(); String path = "file:///" + root; However, on a Nokia S60 5th edition emulator, trying to open a FileConnection to this path throws a java.lang.SecurityException. Apparently S60 devices do not allow connections to the root of the filesystem. I realise I can use something like System.getProperty("fileconn.dir.photos"), but that isn't supported on all devices either. So, my actual question: what is the best approach to get a path to create a FileConnection with, that allows for maximum portability? Thanks. Edit: I suppose I could iterate over all the roots in the Enumeration, and check for a writable one, but that's hardly optimal for two reasons. First, there aren't necessarily any writable roots. Second, this could be the phone memory or a memory card, so the storage method wouldn't be consistent across devices, which is rather ugly.

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• How to use HTTP Live Streaming protocol in iPhone SDk 3.0

  - by Pugal Devan

  Hi Guys, i have developed on IPhone application and submitted to App store. But my application got rejected based on below criteria. Thank you for submitting your yyyyyyyy application. We have reviewed your application and have determined that it cannot be posted to the App Store at this time because it is not using the HTTP Live Streaming protocol to broadcast streaming video. HTTP Live Streaming is required when streaming video feeds over the cellular network, in order to have an optimal user experience and utilize cellular best practices. This protocol automatically determines bandwidth available to users and adjusts the bandwidth appropriately, even as bandwidth streams change. This allows you the flexibility to have as many streams as you like, as long as 64 kbps is set as the baseline feed. In my apps i have to stream prerecorded m4v and mp3 files from my server. I used MPMoviePlayerController to stream and play those videos / audio. How to implement the HTTP Live Streaming Protocol in my apps? Also can i get some sample code? Thanks in advance!

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• Determining the maximum stack depth

  - by Joa Ebert

  Imagine I have a stack-based toy language that comes with the operations Push, Pop, Jump and If. I have a program and its input is the toy language. For instance I get the sequence Push 1 Push 1 Pop Pop In that case the maximum stack would be 2. A more complicated example would use branches. Push 1 Push true If .success Pop Jump .continue .success: Push 1 Push 1 Pop Pop Pop .continue: In this case the maximum stack would be 3. However it is not possible to get the maximum stack by walking top to bottom as shown in this case since it would result in a stack-underflow error actually. CFGs to the rescue you can build a graph and walk every possible path of the basic blocks you have. However since the number of paths can grow quickly for n vertices you get (n-1)! possible paths. My current approach is to simplify the graph as much as possible and to have less possible paths. This works but I would consider it ugly. Is there a better (read: faster) way to attack this problem? I am fine if the algorithm produces a stack depth that is not optimal. If the correct stack size is m then my only constraint is that the result n is n = m. Is there maybe a greedy algorithm available that would produce a good result here?

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• Blackberry stopwatch implementation

  - by Michaela

  I'm trying to write a blackberry app that is basically a stopwatch, and displays lap times. First, I'm not sure I'm implementing the stopwatch functionality in the most optimal way. I have a LabelField (_myLabel) that displays the 'clock' - starting at 00:00. Then you hit the start button and every second the _myLabel field gets updated with how many seconds have past since the last update (should only ever increment by 1, but sometimes there is a delay and it will skip a number). I just can't think of a different way to do it - and I am new to GUI development and threads so I guess that's why. EDIT: Here is what calls the stopwatch: _timer = new Timer(); _timer.schedule(new MyTimerTask(), 250, 250); And here is the TimerTask: class MyTimerTask extends TimerTask { long currentTime; long startTime = System.currentTimeMillis(); public void run() { synchronized (Application.getEventLock()) { currentTime = System.currentTimeMillis(); long diff = currentTime - startTime; long min = diff / 60000; long sec = (diff % 60000) / 1000; String minStr = new Long(min).toString(); String secStr = new Long(sec).toString(); if (min < 10) minStr = "0" + minStr; if (sec < 10) secStr = "0" + secStr; _myLabel.setText(minStr + ":" + secStr); timerDisplay.deleteAll(); timerDisplay.add(_timerLabel); } } } Anyway when you stop the stopwatch it updates a historical table of lap time data. When this list gets long, the timer starts to degrade. If you try to scroll, then it gets really bad. Is there a better way to implement my stopwatch?

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• Finding if a Binary Tree is a Binary Search Tree

  - by dharam

  Today I had an interview where I was asked to write a program which takes a Binary Tree and returns true if it is also a Binary Search Tree otherwise false. My Approach1: Perform an inroder traversal and store the elements in O(n) time. Now scan through the array/list of elements and check if element at ith index is greater than element at (i+1)th index. If such a condition is encountered, return false and break out of the loop. (This takes O(n) time). At the end return true. But this gentleman wanted me to provide an efficient solution. I tried but I was unsuccessfult, because to find if it is a BST I have to check each node. Moreover he was pointing me to think over recusrion. My Approach 2: A BT is a BST if for any node N N-left is < N and N-right N , and the INorder successor of left node of N is less than N and the inorder successor of right node of N is greater than N and the left and right subtrees are BSTs. But this is going to be complicated and running time doesn't seem to be good. Please help if you know any optimal solution. Thanks.

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• Remove duplicates from a sorted ArrayList while keeping some elements from the duplicates

  - by js82

  Okay at first I thought this would be pretty straightforward. But I can't think of an efficient way to solve this. I figured a brute force way to solve this but that's not very elegant. I have an ArrayList. Contacts is a VO class that has multiple members - name, regions, id. There are duplicates in ArrayList because different regions appear multiple times. The list is sorted by ID. Here is an example: Entry 0 - Name: John Smith; Region: N; ID: 1 Entry 1 - Name: John Smith; Region: MW; ID: 1 Entry 2 - Name: John Smith; Region: S; ID: 1 Entry 3 - Name: Jane Doe; Region: NULL; ID: 2 Entry 4 - Name: Jack Black; Region: N; ID: 3 Entry 6 - Name: Jack Black; Region: MW; ID: 3 Entry 7 - Name: Joe Don; Region: NE; ID: 4 I want to transform the list to below by combining duplicate regions together for the same ID. Therefore, the final list should have only 4 distinct elements with the regions combined. So the output should look like this:- Entry 0 - Name: John Smith; Region: N,MW,S; ID: 1 Entry 1 - Name: Jane Doe; Region: NULL; ID: 2 Entry 2 - Name: Jack Black; Region: N,MW; ID: 3 Entry 3 - Name: Joe Don; Region: NE; ID: 4 What are your thoughts on the optimal way to solve this? I am not looking for actual code but ideas or tips to go about the best way to get it done. Thanks for your time!!!

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• How to best handle exception to repeating calendar events

  - by blcArmadillo

  I'm working on a project that will require me to implement a calendar. I'm trying to come up with a system that is very flexible: can handle repeating events, exceptions to repeats, etc. I've looked at the schema for applications like iCal, Lotus Notes, and Mozilla to get an idea of how to go about implementing such a system. Currently I'm having trouble deciding what is the best way to handle exceptions to repeating events. I've used databases quite a bit but don't have a ton of experience with really optimizing everything so I'm not sure which method of the two I'm considering would be optimal in terms of overall performance and ability to query/search: Breaking the repeating event. So taking the changing the ending date on the current row for the repeating event, inserting a new row with the exception, and adding another row continuing the old sequence. Simply adding an exception. So adding a new row with some field that indicates it as an override. So here is why I can't decide. Method one will result in a lot more rows since each edit requires 2 extra rows as apposed to only one row by the second method. On the other hand I think the query to find an event would be much simper, and thus possibly faster(?) using the first method. The second method seems like it will require more calculating on the application server since once you get the data you'll have to remove the intersection of the two rows. I know databases are often the bottleneck for websites and while I'm sure a lot of you are thinking either is fine because your project will probably never get large enough for the difference in efficiency to really matter, I'd still like to implement the best solution. So what method would you guys pick, or would you do something completely different? Also, as a side note I'll be using MySQL and PHP. If there is another technology that you think would be better suited for this, especially in the database area, please mention it. Thanks for the advice.

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• CQRS - The query side

  - by mattcodes

  A lot of the blogsphere articles related to CQRS (command query repsonsibility) seperation seem to imply that all screens/viewmodels are flat. e.g. Name, Age, Location Of Birth etc.. and thus the suggestion that implementation wise we stick them into fast read source etc.. single table per view mySQL etc.. and pull them out with something like primitive SqlDataReader, kick that nasty nhibernate ORM etc.. However, whilst I agree that domain models dont mapped well to most screens, many of the screens that I work with are more dimensional, and Im sure this is pretty common in LOB apps. So my question is how are people handling screen where by for example it displays a summary of customer details and then a list of their orders with a [more detail] link etc.... I thought about keeping with the straight forward SQL query to the Query Database breaking off the outer join so can build a suitable ViewModel to View but it seems like overkill? Alternatively (this is starting to feel yuck) in CustomerSummaryView table have a text/big (whatever the type is in your DB) column called Orders, and the columns for the Order summary screen grid are seperated by , and rows by |. Even with XML datatype it still feeel dirty. Any thoughts on an optimal practice?

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