ORM, EDM, ESQL, Entity Framework, LINQ to SQL, LINQ to Entities - confused?Eric NelsonDeveloper & Platform GroupMicrosoft Ltderic.nelson@microsoft.com http://geekswithblogs.net/IUpdateable http://twitter.com/ericnel

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The plan...

ORMsSwift look at history and future of ORM on Windows

Entity Framework – with demosEntity Data ModelEntity ServicesObject Services

Entity Framework v2 – with no demosOverview of POCO, Model First etc

ORM?

Data Access over the yearsA

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Accessing data in 2005

ADO.NET, Datasets, DataReaders

Accessing data in 2010

• ORM baby!

Object Relational Mapping

What is it?an Abstractiontechnique for working with relational tables as if they were objects in memoryIntention is to hide away the complexity of the underlying tables and give a uniform way of working with data

Why use it?Developer productivityRetain database independence

Note:Using an ORM does not mean you must use the ORM!

ORM on Windows

Many ORMs out thereLLBLGen Pro http://www.llblgen.com/Nhibernate http://www.hibernate.org/343.htmlEntitySpaces http://www.entityspaces.net/Portal/Default.aspxOpen 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 MicrosoftOf 31 .NET ORMs in 2003, 9 lasted to 2008

It was a long wait...2002 to 2008

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

The future of ORM on Windows

Entity Framework and LINQ to Entities is our strategic technology

Entity Framework v2 in VS2010 and .NET Framework 4.0Best of LINQ to SQL moves into LINQ to Entities

Microsoft is using itData Services - shippingReporting ServicesMicrosoft “M”

Partners supporting itDatabase Vendors – IBM,OpenLink, DataDirect, Devart etcORM vendors supporting it

DevForce now target Entity Framework, replacing their ownLLBLGen v3 will target Entity Framework as well as their ownDevart Entity Developer

It is not just about ORM

{ Simple Walkthough }

demo

LINQ to SQL vs LINQ to Entities

LINQ to SQL LINQ to Entities

Database Support SQL Server SQL Server, DB2, Oracle, Sybase, MySQL ...

Object Relational Mapping Capabilities

Simple Complex

Status Not strategic Strategic

Annoying Rarely Often

Quick Overview

Entity Framework is not just about ORMEntity Framework v1 is being adopted

Typically on applications expected to “live” a long time

Entity Framework is only .NET 3.5 SP1 and aboveEntity Framework is probably not the best choice for a “short lived” SQL Server applicationsEntity Framework v1 has “warts”

Designer It is annoying – buggy, clunkyExposes subset of the functionalityDoes not support model first

N-tier storyStored Procedure SupportForeign KeysPoCoGuidsSQL 2008 New Types

Early adopter feedbackCourtesy of twitter

“EF is still cutting development time in half. Ya gotta love it.”“the entity framework can kiss my damn ass - this shit is ridiculous”

http://bit.ly/EFmarmite

Entity Framework

ADO.NET Entity Framework

Tools and services to create an Entity Data Model (EDM)Tools and services for consuming an Entity Data Model

Entity Data Model

Application modelMapped to a persistence store

Comprised of three layers:

Conceptual (CSDL)Mapping (MSL)Storage (SSDL)

Database agnosticComprised of:

EntitiesAssociationsFunctions

Conceptual

Mapping

Storage

Entity Data Model

{ A look at mapping }

demo

Consuming the EDM1

3

2

Object Services

Entity Client

The ORM

- optional

Entity Client

Familiar ADO.NET object model:EntityCommandEntityConnectionEntityDataReaderEntityParameterEntityTransaction

Text-based resultsRead-onlyUses Entity SQL

Object Services

Queries materialized as ObjectsObjectContextObjectQuery<T>

Built on top of Entity ClientTwo query options:

Entity SQLLINQ

Runtime services:Unit of workIdentity trackingEager/explicit loading

{ Consuming an EDM}

demo

Summary of Entity Framework v1

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

Entity Framework

V2

Entity Framework v2 in .NET 4.0

For EveryonePluralizationForeign KeysStored ProceduresSelf tracking Entities

For the Model Centric DeveloperModel FirstComplex TypesModel Defined Functions

For the Control FreakCode Generation

For the AgilistPersistence Ignorance, Lazy Loading, Code Only

+ “Other stuff”

Warning – not final. Expect changes!

For Everyone 1 of 4

PluralizationUsed in Database First and Model FirstImplementation

Public abstract PluralizationService Default implementation is English OnlyDefault rules:

EntityTypes / ComplexTypes are singularizedEntitySets are pluralizedNavigation Properties based on cardinality

For Everyone 2 of 4Foreign Keys

Independent Association – v1  Product p = new Product

{ ID = 1,

      Name = "Bovril",       Category = context.Categories                         .Single(c => c.Name == "Food")}; context.SaveChanges();

FK Association – v2 Product p = new Product

    {         ID = 1,         Name = "Bovril",         CategoryID = 13     };     context.Products.AddObject(p);     context.SaveChanges();

For Everyone 3 of 4

Stored ProceduresStored Procedures as functions

Mapping support for stored procedure resultComplex type as return typeScalar and void return type

Entity CUD using Stored ProceduresNo need to have SPs for all CUD

Self Tracking Entities 4 of 4

Entities do their own change trackingregardless of which tier changes are made on

Somewhere between DTOs and DataSets

For the Model Centric developer

Model FirstStart with a blank model Add entities/relationships (CSDL)Click “Create Database from Model”

Infer Storage Model (SSDL)Infer Mapping (MSL)Infer DDLDeploy DDL

Modify and re-apply. Two way.But - deletes your data!!!

For the Model Centric developer

Complex TypesMap a new type to many typesAdds designer support

Model Defined Functions

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("MyModel", "CustomerFullName")] public static string FullName(this customer c) { return String.Format("{0} {1}", c.FirstName, c.LastName); }

Enables Console.WriteLine(c.FullName());

For the Control Freak

In V1 we had EntityClassGenerator which could be configured using events

Hard (it used CodeDom)Inflexible (not much control)

In V2 we will haveTemplatedEntityClassGenerator and will ship default T4 templatesCustomization via Tools

Uses Workflow Foundation

For the Agilist/Alt.NET folksPersistence Ignorance

Support for Plain Old CLR ObjectsNo requirement to have specific interface, base class

Lazy LoadingCan not do order.order_details.Load()But Can do lazy loadContext.deferredloading=true

For the Agilist/Alt.NET folksCode Only

No XML files, no model!Convention to config

E.g. Convention: xxxID to a primary key, schema=dboE.g. Config: On map to schema sys and class property to table column

[TableMapping(Schema=“sys”,TableName=“MyDBTable”]

[ColumnMapping(PropertyName=“MyClassProp1”, ColumnName=“table_column1”)]

[Key(PropertyName=“MyClassProp1”)]public objectset<MyThing> MyThings...

And more...

Improved N-Tier APIMore LINQ query operatorsMore SQL generation optimizationsInline functions in ESQLReadonly mapping

Conclusion

•Data Access technology remained reasonably static•Procedural, API access•Surfaced the database schema•No clear ORM choice

1990 to 2008 - Tables

•LINQ – excellent addition to the .NET languages•Entity Framework and the EDM – strategic investment•Productivity leap

2009 – Objects

Resources

http://blogs.msdn.com/efdesignEntity Framework v2

http://geekswithblogs.net/IUpdateableSlides

http://bit.ly/BW1Lq EF Performance

© 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.

For the framework developer

Driven by Reporting Services team + othersQuery Tree Writing with no objects...

LINQ query without objects...DbExpression

expression=ctx.EntitySet("Orders").Scan().Where(...);DbDataReader reader = ctx.ExecuteQuery(expression);

Or

from c in ctx.EntitySet(“Orders”).Scan()Select c.Property(“ShipCity”)

Readonly mapping<EntityContainerMapping CdmEntityContainer="CContainer"

StorageEntityContainer="SContainer" GenerateUpdateViews="false" >