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• How/where to run the algorithm on large dataset?

  - by niko

  I would like to run the PageRank algorithm on graph with 4 000 000 nodes and around 45 000 000 edges. Currently I use neo4j graph databse and classic relational database (postgres) and for software projects I mostly use C# and Java. Does anyone know what would be the best way to perform a PageRank computation on such graph? Is there any way to modify the PageRank algorithm in order to run it at home computer or server (48GB RAM) or is there any useful cloud service to push the data along the algorithm and retrieve the results? At this stage the project is at the research stage so in case of using cloud service if possible, would like to use such provider that doesn't require much administration and service setup, but instead focus just on running the algorith once and get the results without much overhead administration work.

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• We Are SQLFamily

  - by AllenMWhite

  On Monday, Tom LaRock ( b /@sqlrockstar) presented his #MemeMonday topic as What #SQLFamily Means To Me . The #sqlfamily hash tag is a relatively new one, but is amazingly appropriate. I've been working with relational databases for almost 20 years, and for most of that time I've been the lone DBA. The only one to set things up, explain how things work, fix the problems, make it go faster, etc., etc., yadda, yadda, yadda. I enjoy being 'the guy', but at the same time it gets hard. What if I'm wrong?...(read more)

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• How do you approach database design?

  - by bron

  I am primarily a web developer and I have a couple of personal projects which I want to kick off. One thing that is bugging me is database design. I have gone through in school db normalization and stuff like that but it has been a couple of years ago and I have never had experience with relational database design except for school. So how you do you approach database from a web app perspective? How do you begin and what do you look out for? What are flags for caution?

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• Opensource showcase for MVC in Java Swing

  - by Regular John

  I've allready created small desktop CRUD applications using Java/Swing. In hindsight I'm not quite sure if the overall design of these applications is good. I've also done some reading on MVC and looked at different Swing-tutorials. My problem is, that I've got a very theroatical knowledge of MVC and on the other hand, most Swing-resources don't implement the MVC-pattern. Now I would like to get my hands dirty and see how MVC is implemented in Swing in a real-world-application. Are there any opensource project you could recommend? It would be also interesting to have more than one project, to see different approaches. Best fit would be a software, that uses a relational database in the backend, to see an overall design, that I can compare to my former applications.

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• In Search of Automatic ORM with REST interface

  - by Dan Ray

  I have this wish that so far Google hasn't been able to fulfill. I want to find a package (ideally in PHP, because I know PHP, but I guess that's not a hard requirement) that you point at a database, it builds an ORM based on what it finds there, and exposes a REST interface over the web. Everything I've found in my searches requires a bunch of code--like, it wants you to build the classes for it, but it'll handle the REST request routing. Or it does database and relational stuff just fine, but you have to build your own methods for all the CRUD actions. That's dumb. REST is well defined. If I wanted to re-invent the wheel, I totally could, but I don't want to. Isn't there somebody who's built a one-shot super-simple auto-RESTing web service package?

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• Subterranean IL: Generics and array covariance

  - by Simon Cooper

  Arrays in .NET are curious beasts. They are the only built-in collection types in the CLR, and SZ-arrays (single dimension, zero-indexed) have their own commands and IL syntax. One of their stranger properties is they have a kind of built-in covariance long before generic variance was added in .NET 4. However, this causes a subtle but important problem with generics. First of all, we need to briefly recap on array covariance. SZ-array covariance To demonstrate, I'll tweak the classes I introduced in my previous posts: public class IncrementableClass { public int Value; public virtual void Increment(int incrementBy) { Value += incrementBy; } } public class IncrementableClassx2 : IncrementableClass { public override void Increment(int incrementBy) { base.Increment(incrementBy); base.Increment(incrementBy); } } In the CLR, SZ-arrays of reference types are implicitly convertible to arrays of the element's supertypes, all the way up to object (note that this does not apply to value types). That is, an instance of IncrementableClassx2[] can be used wherever a IncrementableClass[] or object[] is required. When an SZ-array could be used in this fashion, a run-time type check is performed when you try to insert an object into the array to make sure you're not trying to insert an instance of IncrementableClass into an IncrementableClassx2[]. This check means that the following code will compile fine but will fail at run-time: IncrementableClass[] array = new IncrementableClassx2[1]; array[0] = new IncrementableClass(); // throws ArrayTypeMismatchException These checks are enforced by the various stelem* and ldelem* il instructions in such a way as to ensure you can't insert a IncrementableClass into a IncrementableClassx2[]. For the rest of this post, however, I'm going to concentrate on the ldelema instruction. ldelema This instruction pops the array index (int32) and array reference (O) off the stack, and pushes a pointer (&) to the corresponding array element. However, unlike the ldelem instruction, the instruction's type argument must match the run-time array type exactly. This is because, once you've got a managed pointer, you can use that pointer to both load and store values in that array element using the ldind* and stind* (load/store indirect) instructions. As the same pointer can be used for both input and output to the array, the type argument to ldelema must be invariant. At the time, this was a perfectly reasonable restriction, and maintained array type-safety within managed code. However, along came generics, and with it the constrained callvirt instruction. So, what happens when we combine array covariance and constrained callvirt? .method public static void CallIncrementArrayValue() { // IncrementableClassx2[] arr = new IncrementableClassx2[1] ldc.i4.1 newarr IncrementableClassx2 // arr[0] = new IncrementableClassx2(); dup newobj instance void IncrementableClassx2::.ctor() ldc.i4.0 stelem.ref // IncrementArrayValue<IncrementableClass>(arr, 0) // here, we're treating an IncrementableClassx2[] as IncrementableClass[] dup ldc.i4.0 call void IncrementArrayValue<class IncrementableClass>(!!0[],int32) // ... ret } .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } And the result: Unhandled Exception: System.ArrayTypeMismatchException: Attempted to access an element as a type incompatible with the array. at IncrementArrayValue[T](T[] arr, Int32 index) at CallIncrementArrayValue() Hmm. We're instantiating the generic method as IncrementArrayValue<IncrementableClass>, but passing in an IncrementableClassx2[], hence the ldelema instruction is failing as it's expecting an IncrementableClass[]. On features and feature conflicts What we've got here is a conflict between existing behaviour (ldelema ensuring type safety on covariant arrays) and new behaviour (managed pointers to object references used for every constrained callvirt on generic type instances). And, although this is an edge case, there is no general workaround. The generic method could be hidden behind several layers of assemblies, wrappers and interfaces that make it a requirement to use array covariance when calling the generic method. Furthermore, this will only fail at runtime, whereas compile-time safety is what generics were designed for! The solution is the readonly. prefix instruction. This modifies the ldelema instruction to ignore the exact type check for arrays of reference types, and so it lets us take the address of array elements using a covariant type to the actual run-time type of the array: .method public static void IncrementArrayValue<(IncrementableClass) T>( !!T[] arr, int32 index) { // arr[index].Increment(1) ldarg.0 ldarg.1 readonly. ldelema !!T ldc.i4.1 constrained. !!T callvirt instance void IIncrementable::Increment(int32) ret } But what about type safety? In return for ignoring the type check, the resulting controlled mutability pointer can only be used in the following situations: As the object parameter to ldfld, ldflda, stfld, call and constrained callvirt instructions As the pointer parameter to ldobj or ldind* As the source parameter to cpobj In other words, the only operations allowed are those that read from the pointer; stind* and similar that alter the pointer itself are banned. This ensures that the array element we're pointing to won't be changed to anything untoward, and so type safety within the array is maintained. This is a typical example of the maxim that whenever you add a feature to a program, you have to consider how that feature interacts with every single one of the existing features. Although an edge case, the readonly. prefix instruction ensures that generics and array covariance work together and that compile-time type safety is maintained. Tune in next time for a look at the .ctor generic type constraint, and what it means.

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• 2D Platformer Collision Handling

  - by defender-zone

  Hello, everyone! I am trying to create a 2D platformer (Mario-type) game and I am some having some issues with handling collisions properly. I am writing this game in C++, using SDL for input, image loading, font loading, etcetera. I am also using OpenGL via the FreeGLUT library in conjunction with SDL to display graphics. My method of collision detection is AABB (Axis-Aligned Bounding Box), which is really all I need to start with. What I need is an easy way to both detect which side the collision occurred on and handle the collisions properly. So, basically, if the player collides with the top of the platform, reposition him to the top; if there is a collision to the sides, reposition the player back to the side of the object; if there is a collision to the bottom, reposition the player under the platform. I have tried many different ways of doing this, such as trying to find the penetration depth and repositioning the player backwards by the penetration depth. Sadly, nothing I've tried seems to work correctly. Player movement ends up being very glitchy and repositions the player when I don't want it to. Part of the reason is probably because I feel like this is something so simple but I'm over-thinking it. If anyone thinks they can help, please take a look at the code below and help me try to improve on this if you can. I would like to refrain from using a library to handle this (as I want to learn on my own) or the something like the SAT (Separating Axis Theorem) if at all possible. Thank you in advance for your help! void world1Level1CollisionDetection() { for(int i; i < blocks; i++) { if (de2dCheckCollision(ball,block[i],0.0f,0.0f)==true) { int up = 0; int left = 0; int right = 0; int down = 0; if(ball.coords[0] < block[i].coords[0] && block[i].coords[0] < ball.coords[2] && ball.coords[2] < block[i].coords[2]) { left = 1; } if(block[i].coords[0] < ball.coords[0] && ball.coords[0] < block[i].coords[2] && block[i].coords[2] < ball.coords[2]) { right = 1; } if(ball.coords[1] < block[i].coords[1] && block[i].coords[1] < ball.coords[3] && ball.coords[3] < block[i].coords[3]) { up = 1; } if(block[i].coords[1] < ball.coords[1] && ball.coords[1] < block[i].coords[3] && block[i].coords[3] < ball.coords[3]) { down = 1; } cout << left << ", " << right << ", " << up << ", " << down << ", " << endl; if (left == 1) { ball.coords[0] = block[i].coords[0] - 16.0f; ball.coords[2] = block[i].coords[0] - 0.0f; } if (right == 1) { ball.coords[0] = block[i].coords[2] + 0.0f; ball.coords[2] = block[i].coords[2] + 16.0f; } if (down == 1) { ball.coords[1] = block[i].coords[3] + 0.0f; ball.coords[3] = block[i].coords[3] + 16.0f; } if (up == 1) { ball.yspeed = 0.0f; ball.gravity = 0.0f; ball.coords[1] = block[i].coords[1] - 16.0f; ball.coords[3] = block[i].coords[1] - 0.0f; } } if (de2dCheckCollision(ball,block[i],0.0f,0.0f)==false) { ball.gravity = -0.5f; } } } To explain what some of this code means: The blocks variable is basically an integer that is storing the amount of blocks, or platforms. I am checking all of the blocks using a for loop, and the number that the loop is currently on is represented by integer i. The coordinate system might seem a little weird, so that's worth explaining. coords[0] represents the x position (left) of the object (where it starts on the x axis). coords[1] represents the y position (top) of the object (where it starts on the y axis). coords[2] represents the width of the object plus coords[0] (right). coords[3] represents the height of the object plus coords[1] (bottom). de2dCheckCollision performs an AABB collision detection. Up is negative y and down is positive y, as it is in most games. Hopefully I have provided enough information for someone to help me successfully. If there is something I left out that might be crucial, let me know and I'll provide the necessary information. Finally, for anyone who can help, providing code would be very helpful and much appreciated. Thank you again for your help!

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• Columnstore Case Study #2: Columnstore faster than SSAS Cube at DevCon Security

  - by aspiringgeek

  Preamble This is the second in a series of posts documenting big wins encountered using columnstore indexes in SQL Server 2012 & 2014.  Many of these can be found in my big deck along with details such as internals, best practices, caveats, etc.  The purpose of sharing the case studies in this context is to provide an easy-to-consume quick-reference alternative. See also Columnstore Case Study #1: MSIT SONAR Aggregations Why Columnstore? As stated previously, If we’re looking for a subset of columns from one or a few rows, given the right indexes, SQL Server can do a superlative job of providing an answer. If we’re asking a question which by design needs to hit lots of rows—DW, reporting, aggregations, grouping, scans, etc., SQL Server has never had a good mechanism—until columnstore. Columnstore indexes were introduced in SQL Server 2012. However, they're still largely unknown. Some adoption blockers existed; yet columnstore was nonetheless a game changer for many apps.  In SQL Server 2014, potential blockers have been largely removed & they're going to profoundly change the way we interact with our data.  The purpose of this series is to share the performance benefits of columnstore & documenting columnstore is a compelling reason to upgrade to SQL Server 2014. The Customer DevCon Security provides home & business security services & has been in business for 135 years. I met DevCon personnel while speaking to the Utah County SQL User Group on 20 February 2012. (Thanks to TJ Belt (b|@tjaybelt) & Ben Miller (b|@DBADuck) for the invitation which serendipitously coincided with the height of ski season.) The App: DevCon Security Reporting: Optimized & Ad Hoc Queries DevCon users interrogate a SQL Server 2012 Analysis Services cube via SSRS. In addition, the SQL Server 2012 relational back end is the target of ad hoc queries; this DW back end is refreshed nightly during a brief maintenance window via conventional table partition switching. SSRS, SSAS, & MDX Conventional relational structures were unable to provide adequate performance for user interaction for the SSRS reports. An SSAS solution was implemented requiring personnel to ramp up technically, including learning enough MDX to satisfy requirements. Ad Hoc Queries Even though the fact table is relatively small—only 22 million rows & 33GB—the table was a typical DW table in terms of its width: 137 columns, any of which could be the target of ad hoc interrogation. As is common in DW reporting scenarios such as this, it is often nearly to optimize for such queries using conventional indexing. DevCon DBAs & developers attended PASS 2012 & were introduced to the marvels of columnstore in a session presented by Klaus Aschenbrenner (b|@Aschenbrenner) The Details Classic vs. columnstore before-&-after metrics are impressive. Scenario Conventional Structures Columnstore ? SSRS via SSAS 10 - 12 seconds 1 second >10x Ad Hoc 5-7 minutes (300 - 420 seconds) 1 - 2 seconds >100x Here are two charts characterizing this data graphically.  The first is a linear representation of Report Duration (in seconds) for Conventional Structures vs. Columnstore Indexes.  As is so often the case when we chart such significant deltas, the linear scale doesn’t expose some the dramatically improved values corresponding to the columnstore metrics.  Just to make it fair here’s the same data represented logarithmically; yet even here the values corresponding to 1 –2 seconds aren’t visible.  The Wins Performance: Even prior to columnstore implementation, at 10 - 12 seconds canned report performance against the SSAS cube was tolerable. Yet the 1 second performance afterward is clearly better. As significant as that is, imagine the user experience re: ad hoc interrogation. The difference between several minutes vs. one or two seconds is a game changer, literally changing the way users interact with their data—no mental context switching, no wondering when the results will appear, no preoccupation with the spinning mind-numbing hurry-up-&-wait indicators.  As we’ve commonly found elsewhere, columnstore indexes here provided performance improvements of one, two, or more orders of magnitude. Simplified Infrastructure: Because in this case a nonclustered columnstore index on a conventional DW table was faster than an Analysis Services cube, the entire SSAS infrastructure was rendered superfluous & was retired. PASS Rocks: Once again, the value of attending PASS is proven out. The trip to Charlotte combined with eager & enquiring minds let directly to this success story. Find out more about the next PASS Summit here, hosted this year in Seattle on November 4 - 7, 2014. DevCon BI Team Lead Nathan Allan provided this unsolicited feedback: “What we found was pretty awesome. It has been a game changer for us in terms of the flexibility we can offer people that would like to get to the data in different ways.” Summary For DW, reports, & other BI workloads, columnstore often provides significant performance enhancements relative to conventional indexing.  I have documented here, the second in a series of reports on columnstore implementations, results from DevCon Security, a live customer production app for which performance increased by factors of from 10x to 100x for all report queries, including canned queries as well as reducing time for results for ad hoc queries from 5 - 7 minutes to 1 - 2 seconds. As a result of columnstore performance, the customer retired their SSAS infrastructure. I invite you to consider leveraging columnstore in your own environment. Let me know if you have any questions.

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• SQLAuthority News Microsoft SQL Server 2008 R2 PowerPivot for Microsoft Excel2010

  Microsoft has really and truly created some buzz for PowerPivot. I have been asked to show the demo of Powerpivot in recent time even when I am doing relational database training. Attached is the few details where everyone can download PowerPivot and use the same. Microsoft SQL Server 2008 R2 – PowerPivot for Microsoft Excel [...]...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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• Oracle CRM On Demand Release 24 is Generally Available

  - by Richard Lefebvre

  Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4 We are pleased to announce that Oracle CRM On Demand Release 24 is Generally Available as of October 25, 2013 Get smarter, more productive and the best value with Oracle CRM On Demand Release 24. Oracle CRM On Demand continues to be the most complete Software-as-a-Service (SaaS) CRM solution available. Now, with Release 24, organizations of all types and sizes benefit from actionable insight anywhere, anytime, as well as key enhancements in mobility, embedded social, analytics, integration and extensibility, and ease of use.Next Generation Mobile and Desktop Solutions : Oracle CRM On Demand Release 24 offers a complete set of mobile and desktop solutions that improve productivity by enabling reps to access and update information anywhere, anytime. Capabilities include: Oracle CRM On Demand Disconnected Mobile Sales (DMS) – A disconnected native iPad solution, DMS has been further streamlined mobile sales process by adding Structured Product Messaging to record brand specific call objectives, enhancements in HTML5 eDetailing including message response tracking and improvements in administration and configuration such as more field management options for read only fields, role management and enhanced logging. Oracle CRM On Demand Connected Mobile Sales. This add-on mobile service provides a configurable mobile solution on iOS, BlackBerry and now Android devices. You can access data from CRM On Demand in real time with a rich, native user experience, that is comfortable and familiar to current iOS, BlackBerry and Android users. New features also include Single Sign On to enhance security for mobile users.  Oracle CRM On Demand Desktop: This application centralizes essential CRM information in the familiar Microsoft Outlook environment,increasing user adoption and decreasing training costs. Users can manage CRM data while disconnected, then synchronize bi-directionally when they are back on the network. New in Oracle CRM On Demand Desktop Version 3 is the ability to synchronize by Books of Business, and improved Online Lookup. Mobile Browser Support: The following mobile device browsers are now supported: Apple iPhone, Apple iPad, Windows 8 Tablets, and Google Android. Leverage the Social Enterprise Engaging customers via social channels is rapidly becoming a significant key to enhanced customer experience as it provides proactive customer service, targeted messaging and greater intimacy throughout the entire customer lifecycle. Listening to customers on the social channels can identify a customers’ sphere of influence and the real value they bring to their organization, or the impact they can have on the opportunity. Servicing the customer’s need is the first step towards loyalty to a brand, integrating with social channels allows us to maximize brand affinity and virally expand customer engagements thus increasing revenue. Oracle CRM On Demand is leveraging the Social Enterprise through its integration with Oracle’s Social Relationship Management (SRM) product suite by providing out-of-the-box integration with Social Engagement and Monitoring (SEM), Social Marketing (SM) and Oracle Social Network (OSN). With Oracle CRM On Demand Release 24, users are able to create a service request from a social post via SEM and have leads entered on a SM lead form automatically entered into Oracle CRM On Demand along with the campaign, streamlining the lead qualification process. Get Smarter with Actionable Insight The difference between making good decisions and great decisions depends heavily upon the quality, structure, and availability of information at hand. Oracle CRM On Demand Release 24 expands upon its industry-leading analytics capabilities to provide greater business insight than ever before. New capabilities include flexible permissions on analytics reports folders, allowing for read only access to reports, and additional field and object coverage. Get More Productive with Powerful Tools Oracle CRM On Demand Release 24 introduces a new set of powerful capabilities designed to maximize productivity. A significant new feature for customizing Oracle CRM On Demand is a JavaScript API. The JS API allows customers to add new buttons, suppress existing buttons and even change what happens when a user clicks an existing button. Other usability enhancements, such as personalized related information applets, extended case insensitive search provide users with better, more intuitive, experience. Additional privileges for viewing private activities and notes allow administrators to reassign records as needed, and Custom Object management. Workflow has been added to the Order Item object; and now tasks can be assigned to a relative user, such as an Account Owner, allowing more complex business processes to be automated and adhered to. Get the Best Value Oracle CRM On Demand delivers unprecedented value with the broadest set of capabilities from a single-provider solution, the industry’s lowest total cost of ownership, the most on-demand deployment options, the deepest CRM expertise and experience of any CRM provider, and the most secure CRM in the cloud. With Release 24, Oracle CRM On Demand now includes even more enterprise-grade security, integration, and extensibility features, along with enhanced industry editions to save you time and money. New features include: Business Process Administration: A new privilege has been added that allows administrators to override a Business Process Administration rule.This privilege permits users to edit a locked record, or unlock a record, in the event of a material change that needs to be reflected per corporatepolicy. Additionally, the Products Detailed object has been added to Business Process Administration, enabling record locking and logic to be applied. Expanded Integration: Oracle continues to improve Web Services each release, by adding more object coverage enabling customers and partners to easily integrate with CRM On Demand. Bottom Line Oracle CRM On Demand Release 24 enables organizations to get smarter, get more productive, and get the best value, period. For more information on Oracle CRM On Demand Release 24, please visit oracle.com/crmondemand

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• Cloud INaaS from Data Integration companies

  - by llaszews

  Traditional integration IT vendors are also starting to offer INaaS. Infomatica has been the most aggressive integration vendor when it comes to offering INaaS. Informatica has offered INaaS for over five years and continues to add capabilities, has a number of high profile references, and also continues to add out-of-the-box cloud integration with major COTS and SaaS providers. The Informatica Marketplace contains pre-packaged Informatica Cloud end-points and plug-ins. One such MarketPlace solution, is integration with Oracle E-Business Suite using Informatica integration. The Informatica E-Business Suite INaaS offering includes automatic loading and extraction of data between Salesforce CRM and on-premise systems, cloud-to-cloud, flat files, and relational database. The entire Informatica Cloud integration solution runs in an Informatica managed facility (PaaS). When running in a PaaS environment, Informatica offers an option to keep an exact copy of your cloud-based data on-premise for archival, compliance, and enterprise reporting requirements.

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• ROracle support for TimesTen In-Memory Database

  - by Sam Drake

  Today's guest post comes from Jason Feldhaus, a Consulting Member of Technical Staff in the TimesTen Database organization at Oracle.  He shares with us a sample session using ROracle with the TimesTen In-Memory database.  Beginning in version 1.1-4, ROracle includes support for the Oracle Times Ten In-Memory Database, version 11.2.2. TimesTen is a relational database providing very fast and high throughput through its memory-centric architecture.  TimesTen is designed for low latency, high-volume data, and event and transaction management. A TimesTen database resides entirely in memory, so no disk I/O is required for transactions and query operations. TimesTen is used in applications requiring very fast and predictable response time, such as real-time financial services trading applications and large web applications. TimesTen can be used as the database of record or as a relational cache database to Oracle Database. ROracle provides an interface between R and the database, providing the rich functionality of the R statistical programming environment using the SQL query language. ROracle uses the OCI libraries to handle database connections, providing much better performance than standard ODBC.The latest ROracle enhancements include: Support for Oracle TimesTen In-Memory Database Support for Date-Time using R's POSIXct/POSIXlt data types RAW, BLOB and BFILE data type support Option to specify number of rows per fetch operation Option to prefetch LOB data Break support using Ctrl-C Statement caching support Times Ten 11.2.2 contains enhanced support for analytics workloads and complex queries: Analytic functions: AVG, SUM, COUNT, MAX, MIN, DENSE_RANK, RANK, ROW_NUMBER, FIRST_VALUE and LAST_VALUE Analytic clauses: OVER PARTITION BY and OVER ORDER BY Multidimensional grouping operators: Grouping clauses: GROUP BY CUBE, GROUP BY ROLLUP, GROUP BY GROUPING SETS Grouping functions: GROUP, GROUPING_ID, GROUP_ID WITH clause, which allows repeated references to a named subquery block Aggregate expressions over DISTINCT expressions General expressions that return a character string in the source or a pattern within the LIKE predicate Ability to order nulls first or last in a sort result (NULLS FIRST or NULLS LAST in the ORDER BY clause) Note: Some functionality is only available with Oracle Exalytics, refer to the TimesTen product licensing document for details. Connecting to TimesTen is easy with ROracle. Simply install and load the ROracle package and load the driver. > install.packages("ROracle") > library(ROracle) Loading required package: DBI > drv <- dbDriver("Oracle") Once the ROracle package is installed, create a database connection object and connect to a TimesTen direct driver DSN as the OS user. > conn <- dbConnect(drv, username ="", password="", dbname = "localhost/SampleDb_1122:timesten_direct") You have the option to report the server type - Oracle or TimesTen? > print (paste ("Server type =", dbGetInfo (conn)$serverType)) [1] "Server type = TimesTen IMDB" To create tables in the database using R data frame objects, use the function dbWriteTable. In the following example we write the built-in iris data frame to TimesTen. The iris data set is a small example data set containing 150 rows and 5 columns. We include it here not to highlight performance, but so users can easily run this example in their R session. > dbWriteTable (conn, "IRIS", iris, overwrite=TRUE, ora.number=FALSE) [1] TRUE Verify that the newly created IRIS table is available in the database. To list the available tables and table columns in the database, use dbListTables and dbListFields, respectively. > dbListTables (conn) [1] "IRIS" > dbListFields (conn, "IRIS") [1] "SEPAL.LENGTH" "SEPAL.WIDTH" "PETAL.LENGTH" "PETAL.WIDTH" "SPECIES" To retrieve a summary of the data from the database we need to save the results to a local object. The following call saves the results of the query as a local R object, iris.summary. The ROracle function dbGetQuery is used to execute an arbitrary SQL statement against the database. When connected to TimesTen, the SQL statement is processed completely within main memory for the fastest response time. > iris.summary <- dbGetQuery(conn, 'SELECT SPECIES, AVG ("SEPAL.LENGTH") AS AVG_SLENGTH, AVG ("SEPAL.WIDTH") AS AVG_SWIDTH, AVG ("PETAL.LENGTH") AS AVG_PLENGTH, AVG ("PETAL.WIDTH") AS AVG_PWIDTH FROM IRIS GROUP BY ROLLUP (SPECIES)') > iris.summary SPECIES AVG_SLENGTH AVG_SWIDTH AVG_PLENGTH AVG_PWIDTH 1 setosa 5.006000 3.428000 1.462 0.246000 2 versicolor 5.936000 2.770000 4.260 1.326000 3 virginica 6.588000 2.974000 5.552 2.026000 4 <NA> 5.843333 3.057333 3.758 1.199333 Finally, disconnect from the TimesTen Database. > dbCommit (conn) [1] TRUE > dbDisconnect (conn) [1] TRUE We encourage you download Oracle software for evaluation from the Oracle Technology Network. See these links for our software: Times Ten In-Memory Database,  ROracle.  As always, we welcome comments and questions on the TimesTen and  Oracle R technical forums.

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• Strategies for Indexing Custom Fields in RavenDB

  - by Adrian Thompson Phillips

  In the relational database world, if I was developing a CRM system and wanted to have the user add their own custom fields that are searchable, I could have tables that store the name of the new column, the data type and the value, etc. (which would be less inefficient to index) or I could use the less elegant (but more searchable) solution that software like Dynamics and SharePoint use, whereas I create a load of columns on my aggregate root called CustomInt1, CustomInt2, etc. (which looks dirty and has a limit of how many custom fields a user can have, but has indexing advantages). But my questions is this, in NoSQL databases, what would be the best way of achieving the same thing? My priority would be for searchability. So what would be the best way to store this data? If I used a predefined set of properties (i.e. CustomData1, CustomData2, etc.), because these are all stored as JSON (i.e. strings) in the database, does this make it simpler because I don't have to worry about data types?

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• [News] Le mouvement NoSQL et MongoDB

  Le mouvement "NoSQL" est une communaut? cr??e dans le but de promouvoir les bases de donn?es non relationnelles (d'o? le terme NoSQL). Dans cet hymne ? ce mouvement, Michael Kennedy, instructeur pour DevelopMentor, d?crit les pr?ceptes de NoSQL en l'illustrant ? travers un moteur finalement peu connu du grand public, MongoDB. A lire, tr?s int?ressant m?me si on ne partage pas l'opinion de cette communaut? : "(...) A basic SQL Server cluster might run you $100,000 just to get it up and running on decent hardware. Rather than leveraging crazy scaling-up options, the NoSQL databases let you scale-out. They make this possible (dare I say easy?) by dropping the relational aspects of a database (...) "

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• Google I/O 2010 - Data migration in App Engine

  Google I/O 2010 - Data migration in App Engine Google I/O 2010 - Data migration in App Engine App Engine 201 Matthew Blain Learn about the App Engine bulk loader and see an example of migrating data from an external data source into the app engine datastore--and back out. Do you have data stored in a traditional, relational DB which you'd like to upload to App Engine? This session will teach you how. For all I/O 2010 sessions, please go to code.google.com From: GoogleDevelopers Views: 6 0 ratings Time: 44:26 More in Science & Technology

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• Learn a NoSQL or become a badass with traditional RDMS - Where is/will the work be?

  - by beck

  I'm half way through my MSc and am thinking about my dissertation which I get 3 months to work on full time. Im very comfortable with the traditional Relational Database, the question is should I work on a project where I get a good understanding of something like Cassandra, or should I really push my RDMS knowledge to the limit. Getting great at something like MySQL is a solid safe option, will there really be much work for me with Cassandra in my tool belt? I would love to do either.... Thanks for your opinions and advice.

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• Because of over incumbent patents, is it possible to safely develop any software without the risk of legal action?

  - by Chris Barry

  Take this System and method for restricting user access rights on the internet based on rating information stored in a relational database There are hundreds of thousands of them out there. So basically you can't program anything really without breaching one of thousands of software patents. If your program succeeds you will be sued by someone! Does this happen all the time and people get silenced? Do trendy startups get hit by things like this? Surely all major web properties would have been hit by the example above by AT&T?

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• SQL Peer-to-Peer Dynamic Structured Data Processing Collaboration

  Unstructured and XML semi-structured data is now used more than structured data. But fixed structured data still keeps businesses running day in and day out, which requires consistent predictable highly principled processing for correct results. For this reason, it would be very useful to have a general purpose SQL peer-to-peer collaboration capability that can utilize highly principled hierarchical data processing and its flexible and advanced structured processing to support dynamically structured data and its dynamic structured processing. This flexible dynamic structured processing can change the structure of the data as necessary for the required processing while preserving the relational and hierarchical data principles. This processing will perform freely across remote unrelated peer locations anytime and transparently process unpredictable and unknown structured data and data type changes automatically for immediate processing using automatic metadata maintenance.

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• Thread.Interrupt Is Evil

  - by Alois Kraus

  Recently I have found an interesting issue with Thread.Interrupt during application shutdown. Some application was crashing once a week and we had not really a clue what was the issue. Since it happened not very often it was left as is until we have got some memory dumps during the crash. A memory dump usually means WindDbg which I really like to use (I know I am one of the very few fans of it).  After a quick analysis I did find that the main thread already had exited and the thread with the crash was stuck in a Monitor.Wait. Strange Indeed. Running the application a few thousand times under the debugger would potentially not have shown me what the reason was so I decided to what I call constructive debugging. I did create a simple Console application project and try to simulate the exact circumstances when the crash did happen from the information I have via memory dump and source code reading. The thread that was  crashing was actually MS code from an old version of the Microsoft Caching Application Block. From reading the code I could conclude that the main thread did call the Dispose method on the CacheManger class which did call Thread.Interrupt on the cache scavenger thread which was just waiting for work to do. My first version of the repro looked like this   static void Main(string[] args) { Thread t = new Thread(ThreadFunc) { IsBackground = true, Name = "Test Thread" }; t.Start(); Console.WriteLine("Interrupt Thread"); t.Interrupt(); } static void ThreadFunc() { while (true) { object value = Dequeue(); // block until unblocked or awaken via ThreadInterruptedException } } static object WaitObject = new object(); static object Dequeue() { object lret = "got value"; try { lock (WaitObject) { } } catch (ThreadInterruptedException) { Console.WriteLine("Got ThreadInterruptException"); lret = null; } return lret; } I do start a background thread and call Thread.Interrupt on it and then directly let the application terminate. The thread in the meantime does plenty of Monitor.Enter/Leave calls to simulate work on it. This first version did not crash. So I need to dig deeper. From the memory dump I did know that the finalizer thread was doing just some critical finalizers which were closing file handles. Ok lets add some long running finalizers to the sample. class FinalizableObject : CriticalFinalizerObject { ~FinalizableObject() { Console.WriteLine("Hi we are waiting to finalize now and block the finalizer thread for 5s."); Thread.Sleep(5000); } } class Program { static void Main(string[] args) { FinalizableObject fin = new FinalizableObject(); Thread t = new Thread(ThreadFunc) { IsBackground = true, Name = "Test Thread" }; t.Start(); Console.WriteLine("Interrupt Thread"); t.Interrupt(); GC.KeepAlive(fin); // prevent finalizing it too early // After leaving main the other thread is woken up via Thread.Abort // while we are finalizing. This causes a stackoverflow in the CLR ThreadAbortException handling at this time. } With this changed Main method and a blocking critical finalizer I did get my crash just like the real application. The funny thing is that this is actually a CLR bug. When the main method is left the CLR does suspend all threads except the finalizer thread and declares all objects as garbage. After the normal finalizers were called the critical finalizers are executed to e.g. free OS handles (usually). Remember that I did call Thread.Interrupt as one of the last methods in the Main method. The Interrupt method is actually asynchronous and does wake a thread up and throws a ThreadInterruptedException only once unlike Thread.Abort which does rethrow the exception when an exception handling clause is left. It seems that the CLR does not expect that a frozen thread does wake up again while the critical finalizers are executed. While trying to raise a ThreadInterrupedException the CLR goes down with an stack overflow. Ups not so nice. Why has this nobody noticed for years is my next question. As it turned out this error does only happen on the CLR for .NET 4.0 (x86 and x64). It does not show up in earlier or later versions of the CLR. I have reported this issue on connect here but so far it was not confirmed as a CLR bug. But I would be surprised if my console application was to blame for a stack overflow in my test thread in a Monitor.Wait call. What is the moral of this story? Thread.Abort is evil but Thread.Interrupt is too. It is so evil that even the CLR of .NET 4.0 contains a race condition during the CLR shutdown. When the CLR gurus can get it wrong the chances are high that you get it wrong too when you use this constructs. If you do not believe me see what Patrick Smacchia does blog about Thread.Abort and List.Sort. Not only the CLR creators can get it wrong. The BCL writers do sometimes have a hard time with correct exception handling as well. If you do tell me that you use Thread.Abort frequently and never had problems with it I do suspect that you do not have looked deep enough into your application to find such sporadic errors.

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• Add Widget via Action in Toolbar

  - by Geertjan

  The question of the day comes from Vadim, who asks on the NetBeans Platform mailing list: "Looking for example showing how to add Widget to Scene, e.g. by toolbar button click." Well, the solution is very similar to this blog entry, where you see a solution provided by Jesse Glick for VisiTrend in Boston: https://blogs.oracle.com/geertjan/entry/zoom_capability Other relevant articles to read are as follows: http://netbeans.dzone.com/news/which-netbeans-platform-action http://netbeans.dzone.com/how-to-make-context-sensitive-actions Let's go through it step by step, with this result in the end, a solution involving 4 classes split (optionally, since a central feature of the NetBeans Platform is modularity) across multiple modules: The Customer object has a "name" String and the Droppable capability has a method "doDrop" which takes a Customer object: public interface Droppable {    void doDrop(Customer c);} In the TopComponent, we use "TopComponent.associateLookup" to publish an instance of "Droppable", which creates a new LabelWidget and adds it to the Scene in the TopComponent. Here's the TopComponent constructor: public CustomerCanvasTopComponent() {    initComponents();    setName(Bundle.CTL_CustomerCanvasTopComponent());    setToolTipText(Bundle.HINT_CustomerCanvasTopComponent());    final Scene scene = new Scene();    final LayerWidget layerWidget = new LayerWidget(scene);    Droppable d = new Droppable(){        @Override        public void doDrop(Customer c) {            LabelWidget customerWidget = new LabelWidget(scene, c.getTitle());            customerWidget.getActions().addAction(ActionFactory.createMoveAction());            layerWidget.addChild(customerWidget);            scene.validate();        }    };    scene.addChild(layerWidget);    jScrollPane1.setViewportView(scene.createView());    associateLookup(Lookups.singleton(d));} The Action is displayed in the toolbar and is enabled only if a Droppable is currently in the Lookup: @ActionID(        category = "Tools",        id = "org.customer.controler.AddCustomerAction")@ActionRegistration(        iconBase = "org/customer/controler/icon.png",        displayName = "#AddCustomerAction")@ActionReferences({    @ActionReference(path = "Toolbars/File", position = 300)})@NbBundle.Messages("AddCustomerAction=Add Customer")public final class AddCustomerAction implements ActionListener {    private final Droppable context;    public AddCustomerAction(Droppable droppable) {        this.context = droppable;    }    @Override    public void actionPerformed(ActionEvent ev) {        NotifyDescriptor.InputLine inputLine = new NotifyDescriptor.InputLine("Name:", "Data Entry");        Object result = DialogDisplayer.getDefault().notify(inputLine);        if (result == NotifyDescriptor.OK_OPTION) {            Customer customer = new Customer(inputLine.getInputText());            context.doDrop(customer);        }    }} Therefore, when the Properties window, for example, is selected, the Action will be disabled. (See the Zoomable example referred to in the link above for another example of this.) As you can see above, when the Action is invoked, a Droppable must be available (otherwise the Action would not have been enabled). The Droppable is obtained in the Action and a new Customer object is passed to its "doDrop" method. The above in pictures, take note of the enablement of the toolbar button with the red dot, on the extreme left of the toolbar in the screenshots below: The above shows the JButton is only enabled if the relevant TopComponent is active and, when the Action is invoked, the user can enter a name, after which a new LabelWidget is created in the Scene. The source code of the above is here: http://java.net/projects/nb-api-samples/sources/api-samples/show/versions/7.3/misc/WidgetCreationFromAction Note: Showing this as an MVC example is slightly misleading because, depending on which model object ("Customer" and "Droppable") you're looking at, the V and the C are different. From the point of view of "Customer", the TopComponent is the View, while the Action is the Controler, since it determines when the M is displayed. However, from the point of view of "Droppable", the TopComponent is the Controler, since it determines when the Action, i.e., which is in this case the View, displays the presence of the M.

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• .NET Code Evolution

  - by Alois Kraus

  Originally posted on: http://geekswithblogs.net/akraus1/archive/2013/07/24/153504.aspxAt my day job I do look at a lot of code written by other people. Most of the code is quite good and some is even a masterpiece. And there is also code which makes you think WTF… oh it was written by me. Hm not so bad after all. There are many excuses reasons for bad code. Most often it is time pressure followed by not enough ambition (who cares) or insufficient training. Normally I do care about code quality quite a lot which makes me a (perceived) slow worker who does write many tests and refines the code quite a lot because of the design deficiencies. Most of the deficiencies I do find by putting my design under stress while checking for invariants. It does also help a lot to step into the code with a debugger (sometimes also Windbg). I do this much more often when my tests are red. That way I do get a much better understanding what my code really does and not what I think it should be doing. This time I do want to show you how code can evolve over the years with different .NET Framework versions. Once there was  time where .NET 1.1 was new and many C++ programmers did switch over to get rid of not initialized pointers and memory leaks. There were also nice new data structures available such as the Hashtable which is fast lookup table with O(1) time complexity. All was good and much code was written since then. At 2005 a new version of the .NET Framework did arrive which did bring many new things like generics and new data structures. The “old” fashioned way of Hashtable were coming to an end and everyone used the new Dictionary<xx,xx> type instead which was type safe and faster because the object to type conversion (aka boxing) was no longer necessary. I think 95% of all Hashtables and dictionaries use string as key. Often it is convenient to ignore casing to make it easy to look up values which the user did enter. An often followed route is to convert the string to upper case before putting it into the Hashtable. Hashtable Table = new Hashtable(); void Add(string key, string value) { Table.Add(key.ToUpper(), value); } This is valid and working code but it has problems. First we can pass to the Hashtable a custom IEqualityComparer to do the string matching case insensitive. Second we can switch over to the now also old Dictionary type to become a little faster and we can keep the the original keys (not upper cased) in the dictionary. Dictionary<string, string> DictTable = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase); void AddDict(string key, string value) { DictTable.Add(key, value); } Many people do not user the other ctors of Dictionary because they do shy away from the overhead of writing their own comparer. They do not know that .NET has for strings already predefined comparers at hand which you can directly use. Today in the many core area we do use threads all over the place. Sometimes things break in subtle ways but most of the time it is sufficient to place a lock around the offender. Threading has become so mainstream that it may sound weird that in the year 2000 some guy got a huge incentive for the idea to reduce the time to process calibration data from 12 hours to 6 hours by using two threads on a dual core machine. Threading does make it easy to become faster at the expense of correctness. Correct and scalable multithreading can be arbitrarily hard to achieve depending on the problem you are trying to solve. Lets suppose we want to process millions of items with two threads and count the processed items processed by all threads. A typical beginners code might look like this: int Counter; void IJustLearnedToUseThreads() { var t1 = new Thread(ThreadWorkMethod); t1.Start(); var t2 = new Thread(ThreadWorkMethod); t2.Start(); t1.Join(); t2.Join(); if (Counter != 2 * Increments) throw new Exception("Hmm " + Counter + " != " + 2 * Increments); } const int Increments = 10 * 1000 * 1000; void ThreadWorkMethod() { for (int i = 0; i < Increments; i++) { Counter++; } } It does throw an exception with the message e.g. “Hmm 10.222.287 != 20.000.000” and does never finish. The code does fail because the assumption that Counter++ is an atomic operation is wrong. The ++ operator is just a shortcut for Counter = Counter + 1 This does involve reading the counter from a memory location into the CPU, incrementing value on the CPU and writing the new value back to the memory location. When we do look at the generated assembly code we will see only inc dword ptr [ecx+10h] which is only one instruction. Yes it is one instruction but it is not atomic. All modern CPUs have several layers of caches (L1,L2,L3) which try to hide the fact how slow actual main memory accesses are. Since cache is just another word for redundant copy it can happen that one CPU does read a value from main memory into the cache, modifies it and write it back to the main memory. The problem is that at least the L1 cache is not shared between CPUs so it can happen that one CPU does make changes to values which did change in meantime in the main memory. From the exception you can see we did increment the value 20 million times but half of the changes were lost because we did overwrite the already changed value from the other thread. This is a very common case and people do learn to protect their  data with proper locking.   void Intermediate() { var time = Stopwatch.StartNew(); Action acc = ThreadWorkMethod_Intermediate; var ar1 = acc.BeginInvoke(null, null); var ar2 = acc.BeginInvoke(null, null); ar1.AsyncWaitHandle.WaitOne(); ar2.AsyncWaitHandle.WaitOne(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Intermediate did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Intermediate() { for (int i = 0; i < Increments; i++) { lock (this) { Counter++; } } } This is better and does use the .NET Threadpool to get rid of manual thread management. It does give the expected result but it can result in deadlocks because you do lock on this. This is in general a bad idea since it can lead to deadlocks when other threads use your class instance as lock object. It is therefore recommended to create a private object as lock object to ensure that nobody else can lock your lock object. When you read more about threading you will read about lock free algorithms. They are nice and can improve performance quite a lot but you need to pay close attention to the CLR memory model. It does make quite weak guarantees in general but it can still work because your CPU architecture does give you more invariants than the CLR memory model. For a simple counter there is an easy lock free alternative present with the Interlocked class in .NET. As a general rule you should not try to write lock free algos since most likely you will fail to get it right on all CPU architectures. void Experienced() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Experienced); t1.Wait(); t2.Wait(); if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Experienced did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Experienced() { for (int i = 0; i < Increments; i++) { Interlocked.Increment(ref Counter); } } Since time does move forward we do not use threads explicitly anymore but the much nicer Task abstraction which was introduced with .NET 4 at 2010. It is educational to look at the generated assembly code. The Interlocked.Increment method must be called which does wondrous things right? Lets see: lock inc dword ptr [eax] The first thing to note that there is no method call at all. Why? Because the JIT compiler does know very well about CPU intrinsic functions. Atomic operations which do lock the memory bus to prevent other processors to read stale values are such things. Second: This is the same increment call prefixed with a lock instruction. The only reason for the existence of the Interlocked class is that the JIT compiler can compile it to the matching CPU intrinsic functions which can not only increment by one but can also do an add, exchange and a combined compare and exchange operation. But be warned that the correct usage of its methods can be tricky. If you try to be clever and look a the generated IL code and try to reason about its efficiency you will fail. Only the generated machine code counts. Is this the best code we can write? Perhaps. It is nice and clean. But can we make it any faster? Lets see how good we are doing currently. Level Time in s IJustLearnedToUseThreads Flawed Code Intermediate 1,5 (lock) Experienced 0,3 (Interlocked.Increment) Master 0,1 (1,0 for int[2]) That lock free thing is really a nice thing. But if you read more about CPU cache, cache coherency, false sharing you can do even better. int[] Counters = new int[12]; // Cache line size is 64 bytes on my machine with an 8 way associative cache try for yourself e.g. 64 on more modern CPUs void Master() { var time = Stopwatch.StartNew(); Task t1 = Task.Factory.StartNew(ThreadWorkMethod_Master, 0); Task t2 = Task.Factory.StartNew(ThreadWorkMethod_Master, Counters.Length - 1); t1.Wait(); t2.Wait(); Counter = Counters[0] + Counters[Counters.Length - 1]; if (Counter != 2 * Increments) throw new Exception(String.Format("Hmm {0:N0} != {1:N0}", Counter, 2 * Increments)); Console.WriteLine("Master did take: {0:F1}s", time.Elapsed.TotalSeconds); } void ThreadWorkMethod_Master(object number) { int index = (int) number; for (int i = 0; i < Increments; i++) { Counters[index]++; } } The key insight here is to use for each core its own value. But if you simply use simply an integer array of two items, one for each core and add the items at the end you will be much slower than the lock free version (factor 3). Each CPU core has its own cache line size which is something in the range of 16-256 bytes. When you do access a value from one location the CPU does not only fetch one value from main memory but a complete cache line (e.g. 16 bytes). This means that you do not pay for the next 15 bytes when you access them. This can lead to dramatic performance improvements and non obvious code which is faster although it does have many more memory reads than another algorithm. So what have we done here? We have started with correct code but it was lacking knowledge how to use the .NET Base Class Libraries optimally. Then we did try to get fancy and used threads for the first time and failed. Our next try was better but it still had non obvious issues (lock object exposed to the outside). Knowledge has increased further and we have found a lock free version of our counter which is a nice and clean way which is a perfectly valid solution. The last example is only here to show you how you can get most out of threading by paying close attention to your used data structures and CPU cache coherency. Although we are working in a virtual execution environment in a high level language with automatic memory management it does pay off to know the details down to the assembly level. Only if you continue to learn and to dig deeper you can come up with solutions no one else was even considering. I have studied particle physics which does help at the digging deeper part. Have you ever tried to solve Quantum Chromodynamics equations? Compared to that the rest must be easy ;-). Although I am no longer working in the Science field I take pride in discovering non obvious things. This can be a very hard to find bug or a new way to restructure data to make something 10 times faster. Now I need to get some sleep ….

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• ROracle support for TimesTen In-Memory Database

  - by Sherry LaMonica

  Today's guest post comes from Jason Feldhaus, a Consulting Member of Technical Staff in the TimesTen Database organization at Oracle.  He shares with us a sample session using ROracle with the TimesTen In-Memory database.  Beginning in version 1.1-4, ROracle includes support for the Oracle Times Ten In-Memory Database, version 11.2.2. TimesTen is a relational database providing very fast and high throughput through its memory-centric architecture.  TimesTen is designed for low latency, high-volume data, and event and transaction management. A TimesTen database resides entirely in memory, so no disk I/O is required for transactions and query operations. TimesTen is used in applications requiring very fast and predictable response time, such as real-time financial services trading applications and large web applications. TimesTen can be used as the database of record or as a relational cache database to Oracle Database. ROracle provides an interface between R and the database, providing the rich functionality of the R statistical programming environment using the SQL query language. ROracle uses the OCI libraries to handle database connections, providing much better performance than standard ODBC.The latest ROracle enhancements include: Support for Oracle TimesTen In-Memory Database Support for Date-Time using R's POSIXct/POSIXlt data types RAW, BLOB and BFILE data type support Option to specify number of rows per fetch operation Option to prefetch LOB data Break support using Ctrl-C Statement caching support Times Ten 11.2.2 contains enhanced support for analytics workloads and complex queries: Analytic functions: AVG, SUM, COUNT, MAX, MIN, DENSE_RANK, RANK, ROW_NUMBER, FIRST_VALUE and LAST_VALUE Analytic clauses: OVER PARTITION BY and OVER ORDER BY Multidimensional grouping operators: Grouping clauses: GROUP BY CUBE, GROUP BY ROLLUP, GROUP BY GROUPING SETS Grouping functions: GROUP, GROUPING_ID, GROUP_ID WITH clause, which allows repeated references to a named subquery block Aggregate expressions over DISTINCT expressions General expressions that return a character string in the source or a pattern within the LIKE predicate Ability to order nulls first or last in a sort result (NULLS FIRST or NULLS LAST in the ORDER BY clause) Note: Some functionality is only available with Oracle Exalytics, refer to the TimesTen product licensing document for details. Connecting to TimesTen is easy with ROracle. Simply install and load the ROracle package and load the driver. > install.packages("ROracle") > library(ROracle) Loading required package: DBI > drv <- dbDriver("Oracle") Once the ROracle package is installed, create a database connection object and connect to a TimesTen direct driver DSN as the OS user. > conn <- dbConnect(drv, username ="", password="", dbname = "localhost/SampleDb_1122:timesten_direct") You have the option to report the server type - Oracle or TimesTen? > print (paste ("Server type =", dbGetInfo (conn)$serverType)) [1] "Server type = TimesTen IMDB" To create tables in the database using R data frame objects, use the function dbWriteTable. In the following example we write the built-in iris data frame to TimesTen. The iris data set is a small example data set containing 150 rows and 5 columns. We include it here not to highlight performance, but so users can easily run this example in their R session. > dbWriteTable (conn, "IRIS", iris, overwrite=TRUE, ora.number=FALSE) [1] TRUE Verify that the newly created IRIS table is available in the database. To list the available tables and table columns in the database, use dbListTables and dbListFields, respectively. > dbListTables (conn) [1] "IRIS" > dbListFields (conn, "IRIS") [1] "SEPAL.LENGTH" "SEPAL.WIDTH" "PETAL.LENGTH" "PETAL.WIDTH" "SPECIES" To retrieve a summary of the data from the database we need to save the results to a local object. The following call saves the results of the query as a local R object, iris.summary. The ROracle function dbGetQuery is used to execute an arbitrary SQL statement against the database. When connected to TimesTen, the SQL statement is processed completely within main memory for the fastest response time. > iris.summary <- dbGetQuery(conn, 'SELECT SPECIES, AVG ("SEPAL.LENGTH") AS AVG_SLENGTH, AVG ("SEPAL.WIDTH") AS AVG_SWIDTH, AVG ("PETAL.LENGTH") AS AVG_PLENGTH, AVG ("PETAL.WIDTH") AS AVG_PWIDTH FROM IRIS GROUP BY ROLLUP (SPECIES)') > iris.summary SPECIES AVG_SLENGTH AVG_SWIDTH AVG_PLENGTH AVG_PWIDTH 1 setosa 5.006000 3.428000 1.462 0.246000 2 versicolor 5.936000 2.770000 4.260 1.326000 3 virginica 6.588000 2.974000 5.552 2.026000 4 <NA> 5.843333 3.057333 3.758 1.199333 Finally, disconnect from the TimesTen Database. > dbCommit (conn) [1] TRUE > dbDisconnect (conn) [1] TRUE We encourage you download Oracle software for evaluation from the Oracle Technology Network. See these links for our software: Times Ten In-Memory Database,  ROracle.  As always, we welcome comments and questions on the TimesTen and  Oracle R technical forums.

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• ASP.NET Multi-Select Radio Buttons

  - by Ajarn Mark Caldwell

  “HERESY!” you say, “Radio buttons are for single-select items!  If you want multi-select, use checkboxes!”  Well, I would agree, and that is why I consider this a significant bug that ASP.NET developers need to be aware of.  Here’s the situation. If you use ASP:RadioButton controls on your WebForm, then you know that in order to get them to behave properly, that is, to define a group in which only one of them can be selected by the user, you use the Group attribute and set the same value on each one.  For example: 1: <asp:RadioButton runat="server" ID="rdo1" Group="GroupName" checked="true" /> 2: <asp:RadioButton runat="server" ID="rdo2" Group="GroupName" /> With this configuration, the controls will render to the browser as HTML Input / Type=radio tags and when the user selects one, the browser will automatically deselect the other one so that only one can be selected (checked) at any time. BUT, if you user server-side code to manipulate the Checked attribute of these controls, it is possible to set them both to believe that they are checked. 1: rdo2.Checked = true; // Does NOT change the Checked attribute of rdo1 to be false. As long as you remain in server-side code, the system will believe that both radio buttons are checked (you can verify this in the debugger).  Therefore, if you later have code that looks like this 1: if (rdo1.Checked) 2: { 3: DoSomething1(); 4: } 5: else 6: { 7: DoSomethingElse(); 8: } then it will always evaluate the condition to be true and take the first action.  The good news is that if you return to the client with multiple radio buttons checked, the browser tries to clean that up for you and make only one of them really checked.  It turns out that the last one on the screen wins, so in this case, you will in fact end up with rdo2 as checked, and if you then make a trip to the server to run the code above, it will appear to be working properly.  However, if your page initializes with rdo2 checked and in code you set rdo1 to checked also, then when you go back to the client, rdo2 will remain checked, again because it is the last one and the last one checked “wins”. And this gets even uglier if you ever set these radio buttons to be disabled.  In that case, although the client browser renders the radio buttons as though only one of them is checked the system actually retains the value of both of them as checked, and your next trip to the server will really frustrate you because the browser showed rdo2 as checked, but your DoSomething1() routine keeps getting executed. The following is sample code you can put into any WebForm to test this yourself. 1: <body> 2: <form id="form1" runat="server"> 3: <h1>Radio Button Test</h1> 4: <hr /> 5: <asp:Button runat="server" ID="cmdBlankPostback" Text="Blank Postback" /> 6: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 7: <asp:Button runat="server" ID="cmdEnable" Text="Enable All" OnClick="cmdEnable_Click" /> 8: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 9: <asp:Button runat="server" ID="cmdDisable" Text="Disable All" OnClick="cmdDisable_Click" /> 10: &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; 11: <asp:Button runat="server" ID="cmdTest" Text="Test" OnClick="cmdTest_Click" /> 12: <br /><br /><br /> 13: <asp:RadioButton ID="rdoG1R1" GroupName="Group1" runat="server" Text="Group 1 Radio 1" Checked="true" /><br /> 14: <asp:RadioButton ID="rdoG1R2" GroupName="Group1" runat="server" Text="Group 1 Radio 2" /><br /> 15: <asp:RadioButton ID="rdoG1R3" GroupName="Group1" runat="server" Text="Group 1 Radio 3" /><br /> 16: <hr /> 17: <asp:RadioButton ID="rdoG2R1" GroupName="Group2" runat="server" Text="Group 2 Radio 1" /><br /> 18: <asp:RadioButton ID="rdoG2R2" GroupName="Group2" runat="server" Text="Group 2 Radio 2" Checked="true" /><br /> 19:  20: </form> 21: </body> 1: protected void Page_Load(object sender, EventArgs e) 2: { 3:  4: } 5:  6: protected void cmdEnable_Click(object sender, EventArgs e) 7: { 8: rdoG1R1.Enabled = true; 9: rdoG1R2.Enabled = true; 10: rdoG1R3.Enabled = true; 11: rdoG2R1.Enabled = true; 12: rdoG2R2.Enabled = true; 13: } 14:  15: protected void cmdDisable_Click(object sender, EventArgs e) 16: { 17: rdoG1R1.Enabled = false; 18: rdoG1R2.Enabled = false; 19: rdoG1R3.Enabled = false; 20: rdoG2R1.Enabled = false; 21: rdoG2R2.Enabled = false; 22: } 23:  24: protected void cmdTest_Click(object sender, EventArgs e) 25: { 26: rdoG1R2.Checked = true; 27: rdoG2R1.Checked = true; 28: } 29: 30: protected void Page_PreRender(object sender, EventArgs e) 31: { 32:  33: } After you copy the markup and page-behind code into the appropriate files.  I recommend you set a breakpoint on Page_Load as well as cmdTest_Click, and add each of the radio button controls to the Watch list so that you can walk through the code and see exactly what is happening.  Use the Blank Postback button to cause a postback to the server so you can inspect things without making any changes. The moral of the story is: if you do server-side manipulation of the Checked status of RadioButton controls, then you need to set ALL of the controls in a group whenever you want to change one.

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• Q&amp;A: Will my favourite ORM Foo work with SQL Azure?

  - by Eric Nelson

  short answer: Quite probably, as SQL Azure is very similar to SQL Server longer answer: Object Relational Mappers (ORMs) that work with SQL Server are likely but not guaranteed to work with SQL Azure. The differences between the RDBMS versions are small – but may cause problems, for example in tools used to create the mapping between objects and tables or in generated SQL from the ORM which expects “certain things” :-) More specifically: ADO.NET Entity Framework / LINQ to Entities can be used with SQL Azure, but the Visual Studio designer does not currently work. You will need to point the designer at a version of your database running of SQL Server to create the mapping, then change the connection details to run against SQL Azure. LINQ to SQL has similar issues to ADO.NET Entity Framework above NHibernate can be used against SQL Azure DevExpress XPO supports SQL Azure from version 9.3 DataObjects.Net supports SQL Azure Open Access from Telerik works “seamlessly”  - their words not mine :-) The list above is by no means comprehensive – please leave a comment with details of other ORMs that work (or do not work) with SQL Azure. Related Links: General guidelines and limitations of SQL Azure SQL Azure vs SQL Server

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• Software development, basics of design, conventions and scalability

  - by goce ribeski

  I need to improve my programming skills in order to achieve better scalability for the software I'm working on. Purpose is to learn the rules of adding new modules and features, so when it comes to maintaining existing ones there is some concept. So, I'm looking for a good book, tutorial or websites where I can continue to read about this. Currently, what I know and what I do is: to design relational database(3NF), make separate class for each table put that in MVC implement modular programming ...write code and hope for the best... I presume that next things I need to learn more deeply are: programming codex(naming, commenting, conventions...), organize functions building interfaces organizing custom made libraries, organizing API that I'm using, documenting, team work... ... At last what my job is, it does't need to affect your answer, PHP CodeIgniter developer.

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