This document discusses LINQ to Relational (L2R) in Visual Studio 2008 SP1. It explains that L2R allows querying and modifying relational databases using LINQ syntax. L2R works with existing ADO.NET providers for SQL Server, Oracle, and other databases. L2R provides commonality for querying and modifying data across different data sources using LINQ, while different providers may take different approaches for modifying data. The key aspects of L2R are translating LINQ queries to SQL, materializing query results as objects, and translating data modifications to the appropriate commands.

1. LINQ to “Relational” (L2R) in Visual Studio 2008 SP 1 Mike Taulty Developer & Platform Group Microsoft Ltd [email_address] http://www.miketaulty.com

2. Where Are We?

3. “ Traditional” ADO.NET Data Access App Code Customers ADO.NET DataReader Customers Command “ SELECT * FROM CUSTOMERS” DataSet

4. “ Traditional” ADO.NET Data Access App Code Customers ADO.NET Layer DataReader Customers Command “ SELECT * FROM CUSTOMERS” Data Object Load() Customer FirstName LastName ... Customer FirstName LastName ... Customer FirstName LastName ... Customer FirstName LastName ... ORM

5. Language Integrated Query from data in someDataSource join otherData in someOtherSource on keyExpr equals keyExpr ( into itemName )? let someVariable = someExpression where somePredicate orderby ( expression ( ascending | descending )?)* select expression group expression by keyExpression into itemName .NET Framework V3.5 Service Pack 1 Language Features ( C# V3 and VB V9 ) Custom Objects XML SQL Entities

6. LINQ is not just relational

7. Two Different Styles of LINQ from data in someDataSource join otherData in someOtherSource on keyExpr equals keyExpr ( into itemName )? let someVariable = someExpression where somePredicate orderby ( expression ( ascending | descending )?)* select expression group expression by keyExpression into itemName IEnumerable<T> IQueryable<T>

8. IEnumerable/IQueryable

9. LIN Q is about Query LINQ specifies a standard syntax for querying data LINQ has no standard syntax for modifying data Different API’s take a different approach LINQ to Objects has no approach – unneccessary LINQ to XML LINQ to SQL LINQ to Entities

10. LINQ to Relational ( “L2R” ) LINQ to SQL .NET Framework V3.5 SQL Server databases – 2000, 2005, 2008 & CE Uses existing ADO.NET SQL Provider ADO.NET Entity Framework (“LINQ to Entities”) .NET Framework V3.5 Service Pack 1 Database agnostic Needs modified ADO.NET Providers Microsoft ships SQL and example Oracle provider Various 3 rd party providers in progress

11. L2R – Commonality in Querying App Code Customers “ LINQ” Queryable Object DataReader Customers LINQ Query Call Execute Context GetQueryable<T>() Execute<T>() Customer FirstName LastName ... Customer FirstName LastName ... Customer FirstName LastName ... Materialise objects ADO.NET Provider Translate to SQL ORM Metadata Create

12. L2R – Commonality in Modifying App Code Customers “ LINQ” Context Customer FirstName LastName ... Customer FirstName LastName ... Customer FirstName LastName ... “ Create”<T>() “ Delete”<T> SaveChanges() Create Delete Update State Del Del Del Ins Upd Save ADO.NET Provider Translate to SQL ORM Metadata

13. L2R - Differences

14. LINQ to Relational

15. Resources

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