Entity Framework V1 and V2


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Overview of Entity Framework v1 and a glimpse at v2, due in .NET 4.0

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Entity Framework V1 and V2

  1. 1. Eric Nelson Developer & Platform Group Microsoft Ltd eric.nelson@microsoft.com http://geekswithblogs.net/IUpdateable http://twitter.com/ericnel
  2. 2. Microsoft UK MSDN Flash Newsletter Every two weeks, pure joy enters your Inbox  MSDN Flash Podcast Pilot For feedback http://bit.ly/flashpod1 http://msdn.microsoft.com/uk/flash MSDN Flash eBook 13 of the “Best Technical Technical Authors wanted Articles of 2008” for the Flash – 400 to 500 http://bit.ly/flashebook1 words. Fancy it?
  3. 3. ORMs Swift look at history and future of ORM on Windows Entity Framework – with demos Entity Data Model Entity Services Object Services Entity Framework v2 – with no demos Overview of POCO, Model First etc
  4. 4. Accessing data in 1990 • ODBC, embedded SQL Accessing data in 2000 • ADO, Stored Procedures Accessing data in 2005 • ADO.NET, Datasets, DataReaders Accessing data in 2010 • ORM baby!
  5. 5. What is it? an Abstraction technique for working with relational tables as if they were objects in memory Intention is to hide away the complexity of the underlying tables and give a uniform way of working with data Why use it? Developer productivity Retain database independence Note: Using an ORM does not mean you must use the ORM!
  6. 6. Many ORMs out there LLBLGen Pro http://www.llblgen.com/ Nhibernate http://www.hibernate.org/343.html EntitySpaces http://www.entityspaces.net/Portal/Default.aspx Open Access http://www.telerik.com/products/orm.aspx DevForce http://www.ideablade.com/ XPO http://www.devexpress.com/Products/NET/ORM/ Lightspeed http://www.mindscape.co.nz/products/LightSpeed/default.aspx Plus many, many more No clear “winner” = relatively little adoption of ORM Developers waiting on Microsoft Of 31 .NET ORMs in 2003, 9 lasted to 2008
  7. 7. Typed Datasets (cough) – shipped  ObjectSpaces “v1” – never shipped  ObjectSpaces “v2” – never shipped  Microsoft Business Framework – never shipped  WinFS – never shipped  LINQ to SQL - shipped November 2007  Visual Studio 2008 & .NET Framework 3.5 LINQ to Entities - shipped August 2008  Visual Studio 2008 SP1 & .NET Framework 3.5 SP1 Note: LINQ to Entities is the most visible part of the ADO.NET Entity Framework
  8. 8. Entity Framework and LINQ to Entities is our strategic technology Entity Framework v2 in VS2010 and .NET Framework 4.0 Best of LINQ to SQL moves into LINQ to Entities Microsoft is using it Data Services - shipping Reporting Services Microsoft “M” Partners supporting it Database Vendors – IBM,OpenLink, DataDirect, Devart etc ORM vendors supporting it DevForce now target Entity Framework, replacing their own LLBLGen v3 will target Entity Framework as well as their own Devart Entity Developer It is not just about ORM
  9. 9. { Simple Walkthough }
  10. 10. LINQ to SQL LINQ to Entities Database Support SQL Server SQL Server, DB2, Oracle, Sybase, MySQL ... Object Relational Simple Complex Mapping Capabilities Not strategic  Status Strategic Often  Annoying Rarely
  11. 11. Entity Framework is not just about ORM Entity Framework v1 is being adopted Typically on applications expected to “live” a long time Entity Framework is only .NET 3.5 SP1 and above Entity Framework is probably not the best choice for a “short lived” SQL Server applications Entity Framework v1 has “warts” Designer It is annoying – buggy, clunky Exposes subset of the functionality Does not support model first N-tier story Stored Procedure Support Foreign Keys PoCo Guids SQL 2008 New Types
  12. 12. “EF is still cutting development time “the entity framework in half. Ya gotta can kiss my damn love it.” ass - this shit is ridiculous” http://bit.ly/EFmarmite
  13. 13. Tools and services to create an Entity Data Model (EDM) Tools and services for consuming an Entity Data Model
  14. 14. Entity Data Model Application model Mapped to a persistence store Conceptual Comprised of three layers: Conceptual (CSDL) Mapping (MSL) Mapping Storage (SSDL) Database agnostic Comprised of: Storage Entities Associations Functions
  15. 15. { A look at mapping }
  16. 16. 2 1 The ORM - optional Object Services 3 Entity Client
  17. 17. Familiar ADO.NET object model: EntityCommand EntityConnection EntityDataReader EntityParameter EntityTransaction Text-based results Read-only Uses Entity SQL
  18. 18. Queries materialized as Objects ObjectContext ObjectQuery<T> Built on top of Entity Client Two query options: Entity SQL LINQ Runtime services: Unit of work Identity tracking Eager/explicit loading
  19. 19. { Consuming an EDM}
  20. 20. ORM is an abstraction layer over data • Productivity • Database Independence Microsoft has two ORMs • LINQ to SQL – only SQL Server • Entity Framework (includes LINQ to Entities) – many RDBMS, strategic ADO.NET Entity Framework includes all the other bits  • EDM, Linq to Entities, ESQL, Object Services, Entity Services • Part of .NET Framework 3.5 SP1 Entity Data Model – mapping from conceptual to store • CSDL = Conceptual Schema Definition Language • SSDL = Store Schema Definition Language • MSDL = Mapping Schema Definition Language Two query languages • ESQL = Entity SQL. Read only query language similar to SQL • LINQ to Entities = Language Integrated Query to the EDM
  21. 21. For Everyone Pluralization Foreign Keys Stored Procedures Self tracking Entities For the Model Centric Developer Model First Complex Types Model Defined Functions For the Control Freak Code Generation For the Agilist Persistence Ignorance, Lazy Loading, Code Only + “Other stuff” Warning – not final. Expect changes!
  22. 22. Pluralization Used in Database First and Model First Implementation Public abstract PluralizationService Default implementation is English Only Default rules: EntityTypes / ComplexTypes are singularized EntitySets are pluralized Navigation Properties based on cardinality
  23. 23. Foreign Keys Independent Association – v1 Product p = new Product { ID = 1, Name = quot;Bovrilquot;, Category = context.Categories .Single(c => c.Name == quot;Foodquot;) }; context.SaveChanges(); FK Association – v2 Product p = new Product { ID = 1, Name = quot;Bovrilquot;, CategoryID = 13 }; context.Products.AddObject(p); context.SaveChanges();
  24. 24. Stored Procedures Stored Procedures as functions Mapping support for stored procedure result Complex type as return type Scalar and void return type Entity CUD using Stored Procedures No need to have SPs for all CUD
  25. 25. Entities do their own change tracking regardless of which tier changes are made on Somewhere between DTOs and DataSets
  26. 26. Model First Start with a blank model Add entities/relationships (CSDL) Click “Create Database from Model” Infer Storage Model (SSDL) Infer Mapping (MSL) Infer DDL Deploy DDL Modify and re-apply. Two way. But - deletes your data!!!
  27. 27. Complex Types Map a new type to many types Adds designer support
  28. 28. Model Level using ESQL <Function Name=“CustomerFullName” ReturnType=“String”> <Parameter Name=“customer” Type=“MyModel.customer”> <DefiningExpression> customer.FirstName + ‘ ‘ + customer.LastName </DefiningExpression> </Function> Enables from c in ctx.Customers select c.FullName() CLR Level [EdmFunction(quot;MyModelquot;, quot;CustomerFullNamequot;)] public static string FullName(this customer c) { return String.Format(quot;{0} {1}quot;, c.FirstName, c.LastName); } Enables Console.WriteLine(c.FullName());
  29. 29. In V1 we had EntityClassGenerator which could be configured using events Hard (it used CodeDom) Inflexible (not much control) In V2 we will have TemplatedEntityClassGenerator and will ship default T4 templates Customization via Tools Uses Workflow Foundation
  30. 30. Persistence Ignorance Support for Plain Old CLR Objects No requirement to have specific interface, base class Lazy Loading Can not do order.order_details.Load() But Can do lazy load Context.deferredloading=true
  31. 31. Code Only No XML files, no model! Convention to config E.g. Convention: xxxID to a primary key, schema=dbo E.g. Config: On map to schema sys and class property to table column [TableMapping(Schema=“sys”,TableName=“MyDBTable”] [ColumnMapping(PropertyName=“MyClassProp1”, Column Name=“table_column1”)] [Key(PropertyName=“MyClassProp1”)] public objectset<MyThing> MyThings...
  32. 32. Improved N-Tier API More LINQ query operators More SQL generation optimizations Inline functions in ESQL Readonly mapping
  33. 33. 1990 to • Data Access technology remained reasonably static 2008 - • Procedural, API access • Surfaced the database schema Tables • No clear ORM choice • LINQ – excellent addition to the .NET 2009 – languages • Entity Framework and the EDM – strategic Objects investment • Productivity leap
  34. 34. http://blogs.msdn.com/efdesign Entity Framework v2 http://geekswithblogs.net/IUpdateable Slides http://bit.ly/BW1Lq EF Performance
  35. 35. © 2008 Microsoft Ltd. All rights reserved. Microsoft, Windows, Windows Vista and other product names are or may be registered trademarks and/or trademarks in the U.S. and/or other countries. The information herein is for informational purposes only and represents the current view of Microsoft Corporation as of the date of this presentation. Because Microsoft must respond to changing market conditions, it should not be interpreted to be a commitment on the part of Microsoft, and Microsoft cannot guarantee the accuracy of any information provided after the date of this presentation. MICROSOFT MAKES NO WARRANTIES, EXPRESS, IMPLIED OR STATUTORY, AS TO THE INFORMATION IN THIS PRESENTATION.
  36. 36. Driven by Reporting Services team + others Query Tree Writing with no objects... LINQ query without objects... DbExpression expression=ctx.EntitySet(quot;Ordersquot;).Scan().Where(...); DbDataReader reader = ctx.ExecuteQuery(expression); Or from c in ctx.EntitySet(“Orders”).Scan() Select c.Property(“ShipCity”) Readonly mapping <EntityContainerMapping CdmEntityContainer=quot;CContainerquot; StorageEntityContainer=quot;SContainerquot; GenerateUpdateViews=quot;falsequot; >