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ADO.NET vNextThe Entity Data Model,

Object Services, and LINQ

Bob BeaucheminDirector of Developer Resources, SQLskills

http://www.SQLskills.com/blogs/bobb


About Bob BeaucheminIndependent Consultant/Trainer/Writer/SpeakerDirector of Developer Resources, SQLskills

Website: http://www.SQLskills.comBlog: http://www.SQLskills.com/blogs/bobb

SQL Server MVP

Author of books and numerous resources

related to SQL Server and data access

A Developer's Guide to SQL Server 2005

A First Look at SQL Server 2005 for Developers “Best Book” SQL Server Magazine’s Reader’s Choice Awards (2005)

Essential ADO.NET


Overview

What IS in vNext?The Entity Data ModelEntity ProviderEntity SQLObject ServicesLINQ for EntitiesLINQ for SQLLINQ for DataSet


What is ADO.NET vNext?

A part of Visual Studio Orcas releaseIn .NET Framework 3.5Changes to languages

VB 9.0C# 3.0

CTP available now


What IS in ADO.NET vNext?

A new data modelEntity Data ModelThree XML Schemas for defining and mapping

CSDL - conceptual data language (DDL for EDM)SSDL - store-specific data languageMSL - mapping data language

A set of Object ServicesAn ADO.NET data provider (EntityProvider)Hooks for provider writers

EDM not restricted to SQL Server


What IS in Orcas?

Two new data access languagesLINQEntity SQL (ESQL)

Implementations for databasesLINQ to SQLLINQ to Entities

...and the ADO.NET DataSetLINQ to DataSet


Entity Data Model

Applications model in terms of entitiesEDM is a conceptual model that includes

Structural inheritanceCompositionRelationships as first class types

EDM is not a 1-1 match of the relational model

Entities != RowsCollections != Tables


Views of DataViews of data are layered

Lowest level - physical storageFilegroupsExact layout of rows on diskIndex structureRelational apps unaware of this level

Logical levelTables, Keys, Column ConstraintsPK/FK constructs, "Join tables"Relational modeling works at this level

Conceptual levelEntities and relationshipsEDM modeling works at this level


Uses of the Conceptual Level

Existing tools work at conceptual levelReport Builder - SMDL filesReplication - Transactional replication groupsUDM - Data Source Views in Analysis Services

Each tool uses a slightly different modelEDM could be used to consolidate models


Entity Data Model

Borrows from Relational and E-R modelsBorrows from UML and object modelsConcepts

Entity Types and Entity SetsAssociations and Association SetsComplex typesStructural InheritanceCollections

Entity SQL to query against EDM sets


EDM Description LanguageEDM is a model

Not a physical implementationEDM is described in CSDL

Conceptual Schema Definition LanguageAn XML-based grammarDefines model in terms of

Complex types made up of simple typesInheritanceRelationships

EDM model is mapped to RDBMSSSDL - Describes relational databaseMDL - Maps


Entity SQL LanguageEntity SQL - query language for EDM

Basic relational query concepts +SQL 1999 query concepts +Retrieval as tuples or typesPolymorphic queriesSupport for relationships

Entity SQL is a textual query languageQuery text not programming language specificNo compile-time checking or IntelliSenceCurrently query-only

Update through Object ServicesUpdate through ESQL in future


Object ServicesObject Services provides services for EDM

Fetch semanticsLazy loading option

Change trackingIdentity managementUpdatabilityTransaction support

Object Services uses ESQL to queryUpdates through change tracking layerStored procedures and functions supported

Object Services built over ADO.NET provider


EntityProvider

ADO.NET provider for EDM"Native store" is EDM"Native language" is ESQL

Provider support useful forIntegration with existing toolsFamiliarity for ADO.NET programmers


Wither LINQ?

LINQ is language integrated queryStrong typingIntelliSenseAnonymous types that represent projections

LINQ enables query overObject collectionsXML (LINQ to XML)Relational Databases (LINQ to SQL)ADO.NET DataSet (LINQ to DataSet)EDM (LINQ to Entities)


LINQ and ESQLWhy are there two query languages?

LINQ is programming language basedmultiple types of data as inputcan be extended to new input typesuses LINQ to SQL for database programming

ESQL is data model basedEDM-specific an extension to the SQL languageupdate DML is plannedintegration with DB-centric tools plannedcan use Object Services for database programming

Or ...You can use LINQ to Entities for database programming


LINQ to SQL and EDMLINQ to SQL allows

Object model based on relational modelOne class per tableRelationships (1-1, 1-many, many-many)Inheritance not related to persistenceStored procedures or LINQ Services for inserts, updates, and deletes

EDM mapping allowsEntity model independent of relational modelStructural inheritance and compositionRelationships as first-class typesStored procedures on Object Services for inserts, updates, and deletes

Neither currently supports SQLCLR UDTs


Object Services

EDM is the only "data store"ESQL is the only programming language ADO.NET provider writers can include support for EDM in providers


LINQ Services

LINQ Services useable withLINQ to EntitiesLINQ to SQLLINQ to DataSetXML data

Model is similar for all typesIQueryable<T>

Operations can be expanded with user-defined constructs in code


LINQ Tool Support

In Visual Studio Orcas Mar CTPAdd LINQ to SQL file (dbml)

Can drag tables from Server ExplorerCan drag class definitions from Solution ExplorerCan add properties, associations, inheritance to the modelCan configure insert/update/delete proceduresGenerates classes in project

LINQ - database table DDL generation from dbmlNo relationships or constraints in generated DDL

SQLMetal command line tool for LINQ


EDM Tool Support

In Visual Studio Orcas Mar CTPAdd ADO.NET Entity Model

Can add tables from the databaseGenerates CSDL, SSDL, MSLGenerates classes in projectCan customize using schema-guided XML editor

EDMGen command line tool for EDM


SummaryADO.NET vNext added support for EDM

ADO.NET providerObject ServicesESQL and LINQ for Entities

ADO.NET includes layered approachRich object modelCoexistence with familiar ADO.NET model

with extensions for entitiesObject Services for insert/update/delete, transactions

LINQ for SQL includes straightforward relational mappingTight integration with programming languages

LINQ for DataSets allows queries over DataSet


ResourcesThe LINQ project

http://msdn2.microsoft.com/en-us/netframework/aa904594.aspxADO.NET - Making the Conceptual Level Real

http://msdn2.microsoft.com/en-us/library/aa730866(VS.80).aspxVisual Studio Orcas Forums

http://forums.microsoft.com/MSDN/default.aspx?ForumGroupID=153&SiteID=1ADO.NET Team Blog

http://blogs.msdn.com/adonet Data Blog

http://blogs.msdn.com/data Dinesh's Cyberstation

http://blogs.msdn.com/dinesh.kulkarni mikechampion's weblog

http://blogs.msdn.com/mikechampion Oakleaf Systems

http://oakleafblog.blogspot.com Panopticon Central

http://www.panopticoncentral.netPaul Gielens Thoughts Service

http://weblogs.asp.net/pgielens System.Data.Objects dev guy

http://blogs.msdn.com/dsimmons Tim Mallalieu's Blog

http://blogs.msdn.com/timmall Bob Beauchemin's Blog

http://www.SQLskills.com/blogs/bob


ADO.NET vNextThe Entity Data Model,

Object Services, and LINQBob Beauchemin

Director of Developer Resources, SQLskillshttp://www.SQLskills.com/blogs/bobb

Download - ADO.NET vNext The Entity Data Model, Object Services, and LINQ

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