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LINQ 2 SQL

LINQ 2 SQL. By, Shahzad Sarwar. What you should know, before starting. Anonymous function Anonymous type Anonymous Methods Lamda expression Collection Initializers Object Initializers Extension methods Type Inference

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LINQ 2 SQL

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  1. LINQ 2 SQL By, Shahzad Sarwar

  2. What you should know, before starting • Anonymous function • Anonymous type • Anonymous Methods • Lamda expression • Collection Initializers • Object Initializers • Extension methods • Type Inference • Automatic properties • Partial Methods • Generic • Projection (Later) • Expression Tree (Later)

  3. What is the problem? Class!=Data • 1. strongly-typed queries , what ? • 2. strongly-typed results • Benefits 1. IntelliSense 2. Compile-time error checking.

  4. What is Linq to SQL? 1.OR Mapper API 2.Syntax to query ( LINQ to objects ) 3.Tools • What r OR Mappers(OR/M)? • Not ORM? • What is Object Role Modeling (ORM)? • Associated language FORML (Formal Object-Role Modeling Language) • Supported by Visio and Microsoft Architect • References: http://www.orm.net/

  5. Current Solutions in market • .NET Persistence • BBADataObjects • DataObjects.NET • Data Tier Modeler for .NET • DotNorm • Eldorado.NET • Enterprise Core Objects (ECO™) • Entity Broker • eXpress Persistent Objects for .NET • FastObjects.NET • JC Persistent Framework • LLBLGen Pro • ModelWorks • Nhibernate • Nolics.NET

  6. Current Solutions in market • Norm • Norpheme • ObjectBroker • ObjectSpaces • ObjectSpark • Objectz.NET • OJB.NET • OPF.Net (Object Persistent Framework) • ORM.NET • Pragmatier Data Tier Builder • RapTier • Sisyphus Persistence Framework • TierDeveloper • Bob.NET • ObjectPersistor.NET • Genome

  7. A view of LINQ LINQ Consist of : • Total 6 LINQ implementations • 3 general LINQ technologies • 2 related to relational databases (OR/M) • 1 Future Technologies • LINQ to Objects Over objects , system.linq • LINQ to Dataset over dataset ( LINQ to objects + system.data.dataextension ) • LINQ to SQL- DLinq Direct sql server ( system.data.linq )

  8. LINQ to entities • entities framework ( a part of the ADO.NET Entity Framework which allows LINQ query capabilities) • The Entity Data Model (EDM) is a conceptual data {System.data.entity} • LINQ to XML = xlinq • The low-level XmlReader/XmlWriter API in .NET today. {System.Xml.Linq} • PLINQ Query execution engine accepts any LINQ-to-Objects or LINQ-to-XML query and automatically utilizes multiple processors or cores for execution when they are available.

  9. Conceptual View (LINQ)

  10. Conceptual View (LINQ to Dataset)

  11. Conceptual View (LINQ 2 entities)

  12. Conceptual View ( PLINQ)

  13. References [LINQ to Dataset] • http://blogs.msdn.com/adonet/archive/2007/01/26/querying-datasets-introduction-to-linq-to-dataset.aspx • http://msdn.microsoft.com/en-us/vbasic/bb688086.aspx • http://msdn.microsoft.com/en-us/library/bb386977.aspx • http://www.danielmoth.com/Blog/2007/07/linq-to-dataset.html • http://channel9.msdn.com/posts/DanielMoth/LINQ-to-DataSet/ [LINQ to entities] • http://msdn.microsoft.com/en-us/library/bb386964.aspx • http://dotnetaddict.dotnetdevelopersjournal.com/adoef_vs_linqsql.htm • http://blogs.msdn.com/kaevans/archive/2008/01/29/linq-to-sql-vs-linq-to-entities-smackdown.aspx • http://msdn.microsoft.com/en-us/library/cc161164.aspx

  14. What is difference LINQ to SQ L and LINQ to Entities? • 1:1 vs many to many , complex mapping • sql only , any database .... so run in database specfic pattern. http://msdn.microsoft.com/en-us/library/cc161164.aspx • Sample Application on the fly • Sample Application: Sample Add , delete , edit Example What next ??????????????????????????? It is over…

  15. DataContext • Connection like class (Mixture of a lot of objects) • Caching n change tracking • Example • Log • ExecuteCommand • GetTable • ExecuteQuery • Refresh • ObjectTrackingEnabled • Transaction • Cases: • Nested Query • Cache Query / Multiple context • ToList() • What is Projection?

  16. Context Management • Four Approaches 1. Create a new Context for each atomic operation (Application level management) Problem: pass data objects or the data context itself around to other components in your application. E.g.: if you use business objects there's no real clean way to get a context passed between business objects. 2.Create a global DataContext and handle all operations against this single DataContext object Problem: In other words if you have multiple simulataneous data operations that might not be directly linked/atomic Not possible to do simple update.....? and Options such ObjectTrackingEnabled or DeferredLoadingEnabled can't be set easily Works for desktop , not for Web because of threading ........

  17. Context Management 3.Create a thread specific DataContext Request specific DataContext that is tied to the active thread,Web request to the active ASP.NET HttpContext. Example Factory Pattern 4. Create a per business object DataContext

  18. Architecture Guide Lines References: • http://mtaulty.com/CommunityServer/blogs/mike_taultys_blog/archive/2007/05/10/9322.aspx • http://jonkruger.com/blog/2008/02/10/linq-to-sql-in-disconnectedn-tier-scenarios-saving-an-object/ • http://andrewtokeley.net/archive/2008/07/06/mocking-linq-to-sql-datacontext.aspx • http://devlicio.us/blogs/derik_whittaker/archive/2008/05/21/using-linq-s-datacontext-to-re-create-your-database-for-testing.aspx • http://www.west-wind.com/weblog/posts/246222.aspx • http://blogs.msdn.com/mirceat/archive/2008/03/13/linq-framework-design-guidelines.aspx • http://msdn.microsoft.com/en-us/library/bb882661.aspx

  19. Code Generation • 2 Options • VS Studio OR Designer • SQLMetal • Code Understanding • Explore • XML Mapping file • Generated classes dataConext ,Database, Table, relationships Example

  20. Query pipeline • LINQ 2 Objects = IEnumerable • LINQ 2 SQL= IQueryable public interface IQueryable : IEnumerable { Type ElementType { get; } Expression Expression { get; } IQueryProvider Provider { get; } } • What is Expression Tree? a method of translating executable code into data. • Add-ons: • Query Visualizer • Expression Tree Visualizer • Example • Out of processor , Grammar , sql processor • Various Stages ( Out of scope ) • 1-Many mapping b/q LINQ grammer to db sql References: • http://blogs.msdn.com/charlie/archive/2008/01/31/expression-tree-basics.aspx • http://blogs.msdn.com/charlie/archive/2008/02/13/linq-farm-seed-using-the-expression-tree-visualizer.aspx

  21. Joins n Lazy Loading • Types of Joins • Inner Join • Left Outer Join • Right Outer Join • Cross Join • Example • LINQ implementation of Joins • Deferred Loading of objects • DataLoadOptions/DeferredLoadingEnabled property • AssociateWith Property

  22. LINQDataSource • Like sqlDataSource • Example 1 (Wizard View , declarative View ) • Overriding events • Selecting event • Example 2

  23. Using Store Procedure • Add Store procedures to Model • Example • Add function to Models • Example • Difference b/w Store Procedure n function • for computations , for Business logic • Functions can be called inside select/update/delete stmt but not the procedures.

  24. LINQ2SQL Customization • By Store Procedure • Example • Object validation (Partial classes) • Example • Customize entity class ( 1 to m mapping ) • Example

  25. Inheritance • In OR Mapping, 3 Type • Example

  26. Table per Class Hierarchy [Example]

  27. Table per Subclass

  28. Table per Concrete Class

  29. LINQ Dev. Tools • Visual LINQ Query Builder through a friendly interface http://code.msdn.microsoft.com/vlinq [Demo] • LINQPad http://www.linqpad.net/ Development tool [Demo]

  30. Performance • Benchmark 1 References • http://blogs.msdn.com/ricom/archive/2007/06/22/dlinq-linq-to-sql-performance-part-1.aspx • http://blogs.msdn.com/ricom/archive/2007/06/22/dlinq-linq-to-sql-performance-part-1.aspx

  31. Performance • Adventure Db , Store procedure • So, comparing to the raw ADO.NET - DAAB is 8% slower and LINQ is 28% slower.Comparing to DAAB - LINQ is 18% slower. Reference: • http://alexpinsker.blogspot.com/2007/07/benchmarking-linq-vs.html

  32. Performance • But consider • Productivity • SQL being first class language in VS • Caching of DB. • Change tracking optimization So Over a Great Milestone in Development process

  33. What is Left……………….. • Design Pattern for LINQ to SQL • XLINQ • LINQ to Dataset • LINQ to entities • PLINQ • n……………………. • ….. • ………….. • ……………….. • So Wait for Next presentation on LINQ …………………

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