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Behind every great site, there is great dataEric NelsonDeveloper EvangelistMicrosoft UKhttp://blogs.msdn.com/ericnel

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AgendaData Access Overview

• Data access over the years• ORM anyone?• LINQ and LINQ to SQL• ADO.NET Entity Framework

Drill into Entity Framework • LINQ to Entities• LINQ to SQL vs LINQ to Entities

Using Entity Framework with ASP.NET

• Traditional ASP.NET• ASP.NET Dynamic Data

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Data Access over the yearsAccessing data in 1990• O

DBC, embedded SQL

Accessing data in 2000• A

DO, Stored Procedures

Accessing data in 2005• A

DO.NET, Datasets, DataReaders

Accessing data in 2010• O

RM baby!

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Sidebar: Object Relational MappingWhat is it?

– 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?– Productivity– Retain database independence

Notes– There are many ORMs for .NET developers already in existence. E.g.

– LLBLGen Pro http://www.llblgen.com/– Nhibernate http://www.hibernate.org/343.html– EntitySpaces http://www.entityspaces.net/Portal/Default.aspx

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How did we get here?ObjectSpaces “v1” – never shippedObjectSpaces “v2” – never shippedMicrosoft Business Framework – never shippedWinFS – never shippedLINQ to SQL - shipped November 2007LINQ to Entities - shipped August 2008

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A bit like busesNot one but two ORMs LINQ to SQLLINQ to Entities

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LINQ and LINQ to SQLWhat is it?

– LINQ is not about databases, it is about objects– LINQ = Language-Integrated Query

– Extensions to programming languages to query objects in memory– LINQ to SQL is not about databases, it is about SQL Server

Why use it?– Productivity!!!

Notes– We ship in .NET Framework 3.5

– LINQ to Objects – LINQ to XML– LINQ to Datasets– LINQ to SQL– LINQ to Entities – added in .NET Framework 3.5 SP1

– Others make LINQ to Flickr etc– www.linqpad.net

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Some simple LINQ

Demo

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ADO.NET Entity FrameworkWhat is it?

– Provides tools and services to create an Entity Data Model– Maps entities to database tables

– Provides tools and services for working with an Entity Data Model– Includes ORM capabilities

Why use it?– Productivity– Work with SQL Server, Oracle, DB2 etc– When require complex mapping between entities and database tables– Strategic– Works great with ADO.NET Data Services

Notes– Just released!

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Drill into ADO.NET Entity Framework

•Mapping conceptual to physical•Demo

Entity Data Model

•Traditional queryingEntity Client

•Object based access•DemoObject Services

Sidebar: LINQ to SQL vs LINQ to Entities 1/2

It depends...LINQ to SQL LINQ to Entities

Database Support SQL Server Many

Object Relational Mapping Capabilities

Simple Complex

Requires Attributed .NET Code

No Yes

Status Released Just Released

Sidebar: Similar – but not quite 2/2LINQ to SQL

– var products = from prod in db.Product– where prod.Color == "Blue"– select prod;

LINQ to Entities– var products = from prod in db.Product– where prod.Color == "Blue"– select prod;

In general – LINQ to Entities does more – but not always!Only migration that will ever happen is LINQ to SQL migration to LINQ to Entities

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Entity Data ModelApplication model– Mapped to a persistence store

Comprised of three layers:– Conceptual (CSDL)– Mapping (MSL)– Storage (SSDL)

Database agnosticComprised of:– Entities– Associations– Functions

Conceptual

Mapping

Storage

Entity Data Model

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Creating the Entity Data Model

Demo

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Entity FrameworkEDM consumption options:– Entity Client

– Entity SQL– Object Services

– Entity SQL– LINQ To Entities

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Entity ClientFamiliar ADO.NET object model:– EntityCommand– EntityConnection– EntityDataReader– Entity Parameter– EntityTransaction

Text-based resultsRead-onlyUses Entity SQL

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Object ServicesQueries materialized as Objects– ObjectContext– ObjectQuery<T>

Built on top of Entity ClientTwo query options:– Entity SQL– LINQ

Runtime services:– Unit of work– Identity tracking– Eager/explicit loading

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Entity Framework – Service StackLINQ To Entities

Object Services

Entity SQL

Entity Client

ADO.NET Provider

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Using LINQ to Entities

Demo

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Using Entity Framework with ASP.NET

•New Entity Data SourceTraditional ASP.NET

•Rich web site scaffolding•Works with LINQ to SQL and LINQ to Entities

ASP.NET Dynamic Data

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ASP.NET and Entity Framework

Demo

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The future?

•Across MS Products and Technologies•E.g. Reporting Services?

Entity Framework more widely adopted

•Better ORM capabilities in LINQ to Entities•POCO supportRough edges removed

•Developed “in isolation”•e.g. ASP.NET Dynamic Data and Entity Framework

Technologies work better together

•Less xml editing during developmentBetter tooling

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Conclusion

•Data Access technology remained reasonably static•Procedural, API access•Surfaced the database schema

1990 to 2007 - Tables

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

2008 - Objects

•Plenty more to come2009

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Resourceshttp://blogs.msdn.com/ericnel - all the linksGeneral

– ADO.NET Team Blog http://blogs.msdn.com/adonet– Mike in our team http://www.miketaulty.com ( search Entity or LINQ )– Data Platform Developer Centre

http://msdn.microsoft.com/en-gb/data/default.aspx LINQ

– LINQPad http://www.linqpad.net/ADO.NET Entity Framework

– EF Lead PM http://blogs.msdn.com/dsimmons – FAQ http://blogs.msdn.com/dsimmons/pages/entity-framework-faq.aspx – Entity Framework Design http://blogs.msdn.com/efdesign/default.aspx

ADO.NET Data Services– Team blog http://blogs.msdn.com/astoriateam

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AcronymsEDM = Entity Data Model

EF = ADO.NET Entity Framework

ESQL = Entity SQL

LINQ = Language Integrated Query

CSDL = Conceptual Schema Definition Language

SSDL = Store Schema Definition Language

MSDL = Mapping Schema Definition Language

Lambda Syntax = customer.Select(...)

Comprehension Syntax = from c in customer ...

SQL = Structured Query Language

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Resources

www.microsoft.com/teched Tech·Talks Tech·Ed BloggersLive Simulcasts Virtual Labs

http://msdn.microsoft.com

Developer’s Kit, Licenses, and MORE!

http://microsoft.com/expression

Professional Design tools for tomorrow

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© 2008 Microsoft Corporation. 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.