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• How is technical debt best measured? What metric(s) are most useful?

  - by throp

  If I wanted to help a customer understand the degree of technical debt in his application, what would be the best metric to use? I've stumbled across Erik Doernenburg's code toxicity, and also Sonar's technical debt plugin, but was wondering what others exist. Ideally, I'd like to say "system A has a score of 100 whereas system B has a score of 50, so system A will most likely be more difficult to maintain than system B". Obviously, I understand that boiling down a complex concepts like "technical debt" or "maintainability" into a single number might be misleading or inaccurate (in some cases), however I need a simple way to convey the to a customer (who is not hands-on in the code) roughly how much technical debt is built into their system (relative to other systems), for the goal of building a case for refactoring/unit tests/etc. Again, I'm looking for one single number/graph/visualization, and not a comprehensive list of violations (e.g. CheckStyle, PMD, etc.).

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• How do programmers deal with Project Lead/Managers?

  - by Simon

  Project Managers/Technical Leads sometimes tend to be over enthusiastic when it comes to software. But during code reviews if instead of functionality of the code the only complain one hears is about formatting/spacing and similar trivial things, when there are far better things to discuss (Among other things I have noticed the sometimes during the so called "reviews" suggestions are made that implementation needs a re-write just because it doesnt use the most happening technology/buzzword) How do fellow programmers deal with such scenarios? or is this just a one off? (or is the fault entirely on me )If you have similar experience and what you did to overcome it? Feel free to share.

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• The First Annual Crappy Code Games

  - by Testas

  SQLBits announced some super-exciting news! A tie-up with our platinum sponsor, Fusion-io. Together we'll be running a series of events called "The Crappy Code Games" where SQL Server developers will compete to write the worst-performing code and win some very cool prizes including:   •        Gold: A hands-on, high performance flying day for two at Ultimate High plus Fusion-io flight jackets•        Silver: One day racing experience at Palmer Sports where you will drive seven different high performance cars•        Bronze: Pure Tech Racing 10 person package at PTR’s F1 racing facility includes FI tees, food and drinks. …plus iPods, Windows Mobile phones, X-box 360s, t-shirts and much more. There will be two qualifying events in Manchester on March 17th and London on March 31st, and the third qualifier as well as the grand finale will be held in the evening of Thursday April 7th at SQLBits. And if that isn’t cool enough, Fusion-io's Chief Scientist Steve Wozniak (yes, that Steve Wozniak, tech industry legend and co-founder of Apple) will be on hand in Brighton to hand out the prizes! If you'd like to take part you'll need to register, and since places are limited we recommend you do so right away. For more details and to register, go to http://www.crappycodegames.com/ The Games: In conjunction with SQL Bits, dbA-thletes (that’s you) will compete  head-to-head in one of three separate qualifying events to be held in Manchester, London and Brighton.  Four separate SQL  rounds make up the evening’s Games, and will challenge you to write code that pushes the boundaries of SQL performance.  The four events are: ?  The High Jump: Generate the highest I/O per second ?  The 100 m dash: Cumulative highest number of I/O’s in 60 seconds ?  The SSIS-athon: Load one billion row fact table in the shortest time ?  The Marathon: Generate the highest MB per second in 60 seconds

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• Maintaining packages with code - Adding a property expression programmatically

  Every now and then I've come across scenarios where I need to update a lot of packages all in the same way. The usual scenario revolves around a group of packages all having been built off the same package template, and something needs to updated to keep up with new requirements, a new logging standard for example.You'd probably start by updating your template package, but then you need to address all your existing packages. Often this can run into the hundreds of packages and clearly that's not a job anyone wants to do by hand. I normally solve the problem by writing a simple console application that looks for files and patches any package it finds, and it is an example of this I'd thought I'd tidy up a bit and publish here. This sample will look at the package and find any top level Execute SQL Tasks, and change the SQL Statement property to use an expression. It is very simplistic working on top level tasks only, so nothing inside a Sequence Container or Loop will be checked but obviously the code could be extended for this if required. The code that actually sets the expression is shown below, the rest is just wrapper code to find the package and to find the task. /// <summary> /// The CreationName of the Tasks to target, e.g. Execute SQL Task /// </summary> private const string TargetTaskCreationName = "Microsoft.SqlServer.Dts.Tasks.ExecuteSQLTask.ExecuteSQLTask, Microsoft.SqlServer.SQLTask, Version=9.0.242.0, Culture=neutral, PublicKeyToken=89845dcd8080cc91"; /// <summary> /// The name of the task property to target. /// </summary> private const string TargetPropertyName = "SqlStatementSource"; /// <summary> /// The property expression to set. /// </summary> private const string ExpressionToSet = "@[User::SQLQueryVariable]"; .... // Check if the task matches our target task type if (taskHost.CreationName == TargetTaskCreationName) { // Check for the target property if (taskHost.Properties.Contains(TargetPropertyName)) { // Get the property, check for an expression and set expression if not found DtsProperty property = taskHost.Properties[TargetPropertyName]; if (string.IsNullOrEmpty(property.GetExpression(taskHost))) { property.SetExpression(taskHost, ExpressionToSet); changeCount++; } } } This is a console application, so to specify which packages you want to target you have three options: Find all packages in the current folder, the default behaviour if no arguments are specified TaskExpressionPatcher.exe .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Find all packages in a specified folder, pass the folder as the argument TaskExpressionPatcher.exe C:\Projects\Alpha\Packages\ .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Find a specific package, pass the file path as the argument TaskExpressionPatcher.exe C:\Projects\Alpha\Packages\Package.dtsx The code was written against SQL Server 2005, but just change the reference to Microsoft.SQLServer.ManagedDTS to be the SQL Server 2008 version and it will work fine. If you get an error Microsoft.SqlServer.Dts.Runtime.DtsRuntimeException: The package failed to load due to error 0xC0011008… then check that the package is from the correct version of SSIS compared to the referenced assemblies, 2005 vs 2008 in other words. Download Sample Project TaskExpressionPatcher.zip (6 KB)

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• How do you deal with intentionally bad code?

  - by mafutrct

  There are many stories about intentionally bad code, not only on TDWTF but also on SO. Typical cases include: Having a useless time-wasting construct (e.g. an empty loop counting to some huge value) so programmers can easily "speed up" the application by removing it when they are tasked to. Providing intentionally misleading, wrong or no documentation to generate expensive support requests. Readily generating errors, or worse, generating even though everything worked fine, locking up the application so an expensive support call is required to unlock. These points display a more or less malicious attitude (even though sometimes by accident), especially the first point occurs rather often. How should one deal with such constructs? Ignore the issue, or just remove the offending code? Notify their manager, or speak to the person who introduced the "feature"?

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• Is there any reason to use "plain old data" classes?

  - by Michael

  In legacy code I occasionally see classes that are nothing but wrappers for data. something like: class Bottle { int height; int diameter; Cap capType; getters/setters, maybe a constructor } My understanding of OO is that classes are structures for data and the methods of operating on that data. This seems to preclude objects of this type. To me they are nothing more than structs and kind of defeat the purpose of OO. I don't think it's necessarily evil, though it may be a code smell. Is there a case where such objects would be necessary? If this is used often, does it make the design suspect?

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• How do I overcome paralysis by analysis when coding?

  - by LuxuryMode

  When I start a new project, I often times immediately start thinking about the details of implementation. "Where am I gonna put the DataBaseHandler? How should I use it? Should classes that want to use it extend from some Abstract superclass..? Should I an interface? What level of abstraction am I going to use in my class that contains methods for sending requests and parsing data?" I end up stalling for a long time because I want to code for extensibility and reusability. But I feel it almost impossible to get past thinking about how to implement perfectly. And then, if I try to just say "screw it, just get it done!", I hit a brick wall pretty quickly because my code isn't organized, I mixed levels of abstractions, etc. What are some techniques/methods you have for launching into a new project while also setting up a logical/modular structure that will scale well?

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• Code and Slides: Building the Account at a Glance ASP.NET MVC, EF Code First, HTML5, and jQuery Application

  - by dwahlin

  This presentation was given at the spring 2012 DevConnections conference in Las Vegas and is based on my Pluralsight course. The presentation shows how several different technologies including ASP.NET MVC, EF Code First, HTML5, jQuery, Canvas, SVG, JavaScript patterns, Ajax, and more can be integrated together to build a robust application. An example of the application in action is shown next: View more of my presentations here. The complete code (and associated SQL Server database) for the Account at a Glance application can be found here. Check out the full-length course on the topic at Pluralsight.com.

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• *Code owner* system: is it an efficient way?

  - by sergzach

  There is a new developer in our team. An agile methodology is in use at our company. But the developer has another experience: he considers that particular parts of the code must be assigned to particular developers. So if one developer had created a program procedure or module it would be considered normal that all changes of the procedure/module would be made by him only. On the plus side, supposedly with the proposed approach we save common development time, because each developer knows his part of the code well and makes fixes fast. The downside is that developers don't know the system entirely. Do you think the approach will work well for a medium size system (development of a social network site)?

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• Is there any reason to use "container" classes?

  - by Michael

  I realize the term "container" is misleading in this context - if anyone can think of a better term please edit it in. In legacy code I occasionally see classes that are nothing but wrappers for data. something like: class Bottle { int height; int diameter; Cap capType; getters/setters, maybe a constructor } My understanding of OO is that classes are structures for data and the methods of operating on that data. This seems to preclude objects of this type. To me they are nothing more than structs and kind of defeat the purpose of OO. I don't think it's necessarily evil, though it may be a code smell. Is there a case where such objects would be necessary? If this is used often, does it make the design suspect?

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• I sold my source code to a client, can I now re-build similar code and sell to someone else?

  - by flashhag

  So we built a website and software for a client, charged our fee and handed over the code. The client then got a request from another company about the software. The client passed on the request but said since they owned the code they would need to recieve money for it. I'm thinking there are 2 options here: Work with the client as requested We've actually re-built the software, made it much better and use it for other projects. Am i in my rights to sell that direct to the company that enquired about it instead of going through the client? Any help on this would be much appreciated

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• Organizing code for iOS app development

  - by KronoS

  I've been developing an app for the iOS platform, and as I've been going along, I've noticed that I've done a terrible job of keeping my files (.h, .m, .mm) organized. Is there any industry standards or best practices when it comes to organizing files for an iOS project? My files include custom classes (beside the view controllers), customized View Controllers, third-party content, code that works only on iOS 5.0+ and code that works on previous versions. What I'm looking for is a solution to keep things organized in a manner that others (or myself in years to come) can look at this and understand the basic structure of the application and not get lost in the multiple files found therein.

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• HG: fork web app project to separate API code from app code

  - by cs_brandt

  I have a web app thats been in active development for about 8 months now and its becoming apparent that the project has a need to maintain a separation between app specific code and our OO Javascript API. What I would like to do is have another repository with the following general structure of the js API code. repo_name | +---build | +---build_tools | +---doc | +---src | +---js Of course this structure is different from the original web app directory structure. If I make changes to this new repository how could I pull in those changes to the web app repository without unintentionally removing files or modifying the directory structure of the web app repository?

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• Is extensive documentation a code smell?

  - by Griffin

  Every library, open-source project, and SDK/API I've ever come across has come packaged with a (usually large) documentation file, and this seems contradictory to the wide-spread belief that good code needs little to no comments. What separates documentation from this programming methodology? a one to two page overview of a package seems reasonable, but elegant code combined with standard intelisense should have theoretically deprecated the practice of documentation by now IMO. I feel like companies only create detailed documentation and tutorials because its what they've always done. Why should developers have to constantly be searching through online documentation in order to learn how to do things when such information should be intrinsic to the classes, methods and namespaces?

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• Which is more maintainable -- boolean assignment via if/else or boolean expression?

  - by Bret Walker

  Which would be considered more maintainable? if (a == b) c = true; else c = false; or c = (a == b); I've tried looking in Code Complete, but can't find an answer. I think the first is more readable (you can literally read it out loud), which I also think makes it more maintainable. The second one certainly makes more sense and reduces code, but I'm not sure it's as maintainable for C# developers (I'd expect to see this idiom more in, for example, Python).

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• Nested languages code smell

  - by l0b0

  Many projects combine languages, for example on the web with the ubiquitous SQL + server-side language + markup du jour + JavaScript + CSS mix (often in a single function). Bash and other shell code is mixed with Perl and Python on the server side, evaled and sometimes even passed through sed before execution. Many languages support runtime execution of arbitrary code strings, and in some it seems to be fairly common practice. In addition to advice about security and separation of concerns, what other issues are there with this type of programming, what can be done to minimize it, and is it ever defensible (except in the "PHB on the shoulder" situation)?

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• Resources on learning to program in machine code?

  - by AceofSpades

  I'm a student, fresh into programming and loving it, from Java to C++ and down to C. I moved backwards to the barebones and thought to go further down to Assembly. But, to my surprise, a lot of people said it's not as fast as C and there is no use. They suggested learning either how to program a kernel or writing a C compiler. My dream is to learn to program in binary (machine code) or maybe program bare metal (program micro-controller physically) or write bios or boot loaders or something of that nature. The only possible thing I heard after so much research is that a hex editor is the closest thing to machine language I could find in this age and era. Are there other things I'm unaware of? Are there any resources to learn to program in machine code? Preferably on a 8-bit micro-controller/microprocessor. This question is similar to mine, but I'm interested in practical learning first and then understanding the theory.

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• Coordinating team code review sessions [closed]

  - by Wade Tandy

  My question has two parts: 1) In your team or organization, do you ever do in-person code reviews with all or part of a team, as opposed to online reviews using some sort of tool? 2) How do you structure these meetings? Do you choose to focus on one person's code in a given meeting? Do you look at everything? Take a random sample? Ask people on the team what they'd like to have looked at of theirs? I'd love to add this practice to my development team, so I'd like to hear how others are doing it.

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• Why are 20% of keywords still provided when Google is using HTTPS across the board?

  - by Rajesh Magar

  Most of the searches that appear in my analytics are "not provided" because Google has encrypted their all searches. However, if all search results are now encrypted with HTTPS protocol then how is Google analytics still able to track some (20%) of the organic keywords details? There are still some keywords appearing in my organic keywords section. So how did Google analytics do this tracking? Does it bypass the HTTPS restrictions for the referrer?

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• Has anyone had issues with Google Analyticator authenticating?

  - by Marc Benzakein

  I'm using Analyticator on a site and am having an issue. I am getting an error (see below) when I go to authenticate from the settings panel on Analyticator. The structure on this is a bit different and I think that's what is causing it. The website is on a subdomain which is hosted on a different server than the top-level domain. The analytics account on google only has the subdomain listed. Is it possible that the reason for the error is that the primary domain either: A. doesn't have an Analytics account or B. does have an Analytics account but it is not linked to the Analytics account of the subdomain? The page you have requested cannot be displayed. Another site was requesting access to your Google Account, but sent a malformed request. Please contact the site that you were trying to use when you received this message to inform them of the error. A detailed error message follows: The site "http://xxxxx.com" has not been registered.

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• Microsoft Silverlight Analytics Framework - Day 2 Part 2 of MIX 2010

  - by GeekAgilistMercenary

  I went to the session on Microsoft Silverlight Analytics Framework (MSAF) today while here at MIX 2010.  It was a great walk through the features, ideas, and what the end goal is.  Michael Scherotter did a great job of lining up the ideas, intentions, and the functional ideas behind the framework. The framework is built around the Silverlight Behaviors.  If you aren't sure what behaviors are, check out these entries from Nikhilk.net Silverlight Behaviors, Silverlight 3 Drag Behavior, An Introduction to Behaviors, Triggers, and Actions, and of course the MSDN Documentation on the matter. Some of the key features of the framework is to support out-of-browser scenarios, which works perfectly with out Webtrends DX Web Services.  Offline scenarios, which again, we have worked toward supporting at Webtrends DC Web Services via caching and other criteria as needed.  Another feature that I was really stoked about is the Microsoft Expression Blend integration that removes the need for coding, thus simplifying the addition of analytics components based on events or other actions within a Silverlight Application.  This framework also easily supports A/B Testing (again, something we do quit a bit of at Webtrends with Webtrends Optimize. The last thing I really wanted to point out was the control support that this framework has support in already from Telerik RadControls, Smooth Streaming Media Element, and Microsoft Silverlight Media Framework Player 1.0.  These are implemented with behaviors and handlers exposed via MEF (Managed Extensibility Framework). All in all, great second day, great analytics framework for Silverlight, and great presentation.  Until tomorrow, adieu. For this original entry and all sorts of other technical gibberish I write, check out my other blog Agilist Mercenary.

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• OpenWorld Session: BPM Analytics - Process Dashboards, BAM and Intelligent Optimization

  - by Ajay Khanna

  Blog Contributed by Payal Srivastava, Oracle Product Mamagement   Margin of error for the business is shrinking dramatically. Business needs to accomplish more with less i.e. minimal investment with quick ROI. Learn how you can leverage Oracle BPM suite and complementary technologies to create a robust analytics capability to provide visibility into operations to  C-level executives and Operational managers. We will talk about BPM analytics options available today that will not only enhance the visibility but allow you to intelligently optimize the business process at design time as well as run time.  The session will share some exciting this on our roadmap.  Come meet with the Oracle team members  from Product Development (Avinash Dabholkar , Eric Hsiao) and Product Management (Payal Srivastava) at the session. We would like to hear  your questions/comments about  our offering and roadmap. BPM Analytics: Process Dashboards, BAM and Intelligent Optimization, Moscone South 308, 10/3/12 @11:45am – CON 8598

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• EMEA Analytics & Data Integration Oracle Partner Forum

  - by Mike.Hallett(at)Oracle-BI&EPM

  MONDAY 12TH NOVEMBER, 2012 IN LONDON (UK) For Oracle Partners across Europe, Middle East and Africa: come to hear the latest news from Oracle OpenWorld about Oracle BI & Data Integration, and propel your business growth as an Oracle partner. This event should appeal to BI or Data Integration specialised partners, Executives, Sales, Pre-sales and Solution architects: with a choice of participation in the plenary day and then a set of special interest (technical) sessions. The follow on breakout sessions from the 13th November provide deeper dives and technical training for those of you who wish to stay for more detailed and hands-on workshops. Keynote: Andrew Sutherland, SVP Oracle Technology Hot agenda items will include: The Fusion Middleware Stack: Engineered to work together A complete Analytics and Data Integration Solution Architecture: Big Data and Little Data combined In-Memory Analytics for Extreme Insight Latest Product Development Roadmap for Data Integration and Analytics Venue:  Oracles London CITY Moorgate Offices Places are limited, Register from this Link {see Register button at bottom right of page}. Note: Registration for the conference and the deeper dives and technical training is free of charge to OPN member Partners, but you will be responsible for your own travel and hotel expenses. Event Schedule During this event you can learn about partner success stories, participate in an array of break-out sessions, exchange information with other partners and enjoy a vibrant panel discussion. Nov. 12th  : Day 1 Main Plenary Session : Full day, starting 10.30 am.     Oracle Hosted Dinner in the Evening Nov. 13th  onwards Architecture Masterclass : IM Reference Architecture – Big Data and Little Data combined (1 day) BI-Apps Bootcamp  (4-days) Oracle GoldenGate workshop (1 day) Oracle Data Integrator and Oracle Enterprise Data Quality workshop (1 day)   For further information and detail download the Agenda (pdf) or contact Michael Hallett at [email protected].

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• Basic Google Analytics Click Tracking and/or Overview

  - by Alan Storm

  This is a really basic Google Analytics question. Apologies in advance if it's not appropriate here, but I've had a lot of luck on Stack Overflow and this seems like the best Stack Exchange site for a question like this. I'm trying to understand how Google Analytics goals work, or if they're the right feature to be using for my situation. Most of the documentation I find online refers to the old version of the UI, not the new one. I have a website, let's call is blog.example.com. This website drives traffic to an ecommerce store, let's call that store.example2.com. I want to get reports on which links from blog.example.com are being clicked through leading to store.example2.com. How do you do this in Google analytics? Are goals the right area to be looking? Do I setup the goals on store.example2.com or blog.example.com? Or both? Is there any canonical user guide (free or paid) that covers how this works? I'm a competent programmer, but it's years since I dealt with conversion tracking on any serious level, and we've progressed well beyond my frozen caveman pixel tracking knowledge. Thanks in advance

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• Inheritance Mapping Strategies with Entity Framework Code First CTP5: Part 2 – Table per Type (TPT)

  - by mortezam

  In the previous blog post you saw that there are three different approaches to representing an inheritance hierarchy and I explained Table per Hierarchy (TPH) as the default mapping strategy in EF Code First. We argued that the disadvantages of TPH may be too serious for our design since it results in denormalized schemas that can become a major burden in the long run. In today’s blog post we are going to learn about Table per Type (TPT) as another inheritance mapping strategy and we'll see that TPT doesn’t expose us to this problem. Table per Type (TPT)Table per Type is about representing inheritance relationships as relational foreign key associations. Every class/subclass that declares persistent properties—including abstract classes—has its own table. The table for subclasses contains columns only for each noninherited property (each property declared by the subclass itself) along with a primary key that is also a foreign key of the base class table. This approach is shown in the following figure: For example, if an instance of the CreditCard subclass is made persistent, the values of properties declared by the BillingDetail base class are persisted to a new row of the BillingDetails table. Only the values of properties declared by the subclass (i.e. CreditCard) are persisted to a new row of the CreditCards table. The two rows are linked together by their shared primary key value. Later, the subclass instance may be retrieved from the database by joining the subclass table with the base class table. TPT Advantages The primary advantage of this strategy is that the SQL schema is normalized. In addition, schema evolution is straightforward (modifying the base class or adding a new subclass is just a matter of modify/add one table). Integrity constraint definition are also straightforward (note how CardType in CreditCards table is now a non-nullable column). Another much more important advantage is the ability to handle polymorphic associations (a polymorphic association is an association to a base class, hence to all classes in the hierarchy with dynamic resolution of the concrete class at runtime). A polymorphic association to a particular subclass may be represented as a foreign key referencing the table of that particular subclass. Implement TPT in EF Code First We can create a TPT mapping simply by placing Table attribute on the subclasses to specify the mapped table name (Table attribute is a new data annotation and has been added to System.ComponentModel.DataAnnotations namespace in CTP5): public abstract class BillingDetail {     public int BillingDetailId { get; set; }     public string Owner { get; set; }     public string Number { get; set; } } [Table("BankAccounts")] public class BankAccount : BillingDetail {     public string BankName { get; set; }     public string Swift { get; set; } } [Table("CreditCards")] public class CreditCard : BillingDetail {     public int CardType { get; set; }     public string ExpiryMonth { get; set; }     public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext {     public DbSet<BillingDetail> BillingDetails { get; set; } } If you prefer fluent API, then you can create a TPT mapping by using ToTable() method: protected override void OnModelCreating(ModelBuilder modelBuilder) {     modelBuilder.Entity<BankAccount>().ToTable("BankAccounts");     modelBuilder.Entity<CreditCard>().ToTable("CreditCards"); } Generated SQL For QueriesLet’s take an example of a simple non-polymorphic query that returns a list of all the BankAccounts: var query = from b in context.BillingDetails.OfType<BankAccount>() select b; Executing this query (by invoking ToList() method) results in the following SQL statements being sent to the database (on the bottom, you can also see the result of executing the generated query in SQL Server Management Studio): Now, let’s take an example of a very simple polymorphic query that requests all the BillingDetails which includes both BankAccount and CreditCard types: projects some properties out of the base class BillingDetail, without querying for anything from any of the subclasses: var query = from b in context.BillingDetails             select new { b.BillingDetailId, b.Number, b.Owner }; -- var query = from b in context.BillingDetails select b; This LINQ query seems even more simple than the previous one but the resulting SQL query is not as simple as you might expect: -- As you can see, EF Code First relies on an INNER JOIN to detect the existence (or absence) of rows in the subclass tables CreditCards and BankAccounts so it can determine the concrete subclass for a particular row of the BillingDetails table. Also the SQL CASE statements that you see in the beginning of the query is just to ensure columns that are irrelevant for a particular row have NULL values in the returning flattened table. (e.g. BankName for a row that represents a CreditCard type) TPT ConsiderationsEven though this mapping strategy is deceptively simple, the experience shows that performance can be unacceptable for complex class hierarchies because queries always require a join across many tables. In addition, this mapping strategy is more difficult to implement by hand— even ad-hoc reporting is more complex. This is an important consideration if you plan to use handwritten SQL in your application (For ad hoc reporting, database views provide a way to offset the complexity of the TPT strategy. A view may be used to transform the table-per-type model into the much simpler table-per-hierarchy model.) SummaryIn this post we learned about Table per Type as the second inheritance mapping in our series. So far, the strategies we’ve discussed require extra consideration with regard to the SQL schema (e.g. in TPT, foreign keys are needed). This situation changes with the Table per Concrete Type (TPC) that we will discuss in the next post. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

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