ADO'NET vNext The Entity Data Model, Object Services, and LINQ

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ADO.NET vNextThe Entity Data Model, Object
Services, and LINQ

• Bob Beauchemin
• Director of Developer Resources, SQLskills
• http//www.SQLskills.com/blogs/bobb

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About Bob Beauchemin

• Independent Consultant/Trainer/Writer/Speaker
• Director of Developer Resources, SQLskills
• Website http//www.SQLskills.com
• Blog 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 Magazines Readers Choice
  Awards (2005)
• Essential ADO.NET

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Overview

• What IS in vNext?
• The Entity Data Model
• Entity Provider
• Entity SQL
• Object Services
• LINQ for Entities
• LINQ for SQL
• LINQ for DataSet

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What is ADO.NET vNext?

• A part of Visual Studio Orcas release
• In .NET Framework 3.5
• Changes to languages
• VB 9.0
• C 3.0
• CTP available now

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What IS in ADO.NET vNext?

• A new data model
• Entity Data Model
• Three XML Schemas for defining and mapping
• CSDL - conceptual data language (DDL for EDM)
• SSDL - store-specific data language
• MSL - mapping data language
• A set of Object Services
• An ADO.NET data provider (EntityProvider)
• Hooks for provider writers
• EDM not restricted to SQL Server

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What IS in Orcas?

• Two new data access languages
• LINQ
• Entity SQL (ESQL)
• Implementations for databases
• LINQ to SQL
• LINQ to Entities
• ...and the ADO.NET DataSet
• LINQ to DataSet

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Entity Data Model

• Applications model in terms of entities
• EDM is a conceptual model that includes
• Structural inheritance
• Composition
• Relationships as first class types
• EDM is not a 1-1 match of the relational model
• Entities ! Rows
• Collections ! Tables

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Views of Data

• Views of data are layered
• Lowest level - physical storage
• Filegroups
• Exact layout of rows on disk
• Index structure
• Relational apps unaware of this level
• Logical level
• Tables, Keys, Column Constraints
• PK/FK constructs, "Join tables"
• Relational modeling works at this level
• Conceptual level
• Entities and relationships
• EDM modeling works at this level

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Uses of the Conceptual Level

• Existing tools work at conceptual level
• Report Builder - SMDL files
• Replication - Transactional replication groups
• UDM - Data Source Views in Analysis Services
• Each tool uses a slightly different model
• EDM could be used to consolidate models

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Entity Data Model

• Borrows from Relational and E-R models
• Borrows from UML and object models
• Concepts
• Entity Types and Entity Sets
• Associations and Association Sets
• Complex types
• Structural Inheritance
• Collections
• Entity SQL to query against EDM sets

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EDM Description Language

• EDM is a model
• Not a physical implementation
• EDM is described in CSDL
• Conceptual Schema Definition Language
• An XML-based grammar
• Defines model in terms of
• Complex types made up of simple types
• Inheritance
• Relationships
• EDM model is mapped to RDBMS
• SSDL - Describes relational database
• MDL - Maps

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Entity SQL Language

• Entity SQL - query language for EDM
• Basic relational query concepts
• SQL 1999 query concepts
• Retrieval as tuples or types
• Polymorphic queries
• Support for relationships
• Entity SQL is a textual query language
• Query text not programming language specific
• No compile-time checking or IntelliSence
• Currently query-only
• Update through Object Services
• Update through ESQL in future

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Object Services

• Object Services provides services for EDM
• Fetch semantics
• Lazy loading option
• Change tracking
• Identity management
• Updatability
• Transaction support
• Object Services uses ESQL to query
• Updates through change tracking layer
• Stored procedures and functions supported
• Object Services built over ADO.NET provider

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EntityProvider

• ADO.NET provider for EDM
• "Native store" is EDM
• "Native language" is ESQL
• Provider support useful for
• Integration with existing tools
• Familiarity for ADO.NET programmers

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Wither LINQ?

• LINQ is language integrated query
• Strong typing
• IntelliSense
• Anonymous types that represent projections
• LINQ enables query over
• Object collections
• XML (LINQ to XML)
• Relational Databases (LINQ to SQL)
• ADO.NET DataSet (LINQ to DataSet)
• EDM (LINQ to Entities)

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LINQ and ESQL

• Why are there two query languages?
• LINQ is programming language based
• multiple types of data as input
• can be extended to new input types
• uses LINQ to SQL for database programming
• ESQL is data model based
• EDM-specific
• an extension to the SQL language
• update DML is planned
• integration with DB-centric tools planned
• can use Object Services for database programming
• Or ...
• You can use LINQ to Entities for database
  programming

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LINQ to SQL and EDM

• LINQ to SQL allows
• Object model based on relational model
• One class per table
• Relationships (1-1, 1-many, many-many)
• Inheritance not related to persistence
• Stored procedures or LINQ Services for inserts,
  updates, and deletes
• EDM mapping allows
• Entity model independent of relational model
• Structural inheritance and composition
• Relationships as first-class types
• Stored procedures on Object Services for inserts,
  updates, and deletes
• Neither currently supports SQLCLR UDTs

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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

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LINQ Services

• LINQ Services useable with
• LINQ to Entities
• LINQ to SQL
• LINQ to DataSet
• XML data
• Model is similar for all types
• IQueryableltTgt
• Operations can be expanded with user-defined
  constructs in code

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LINQ Tool Support

• In Visual Studio Orcas Mar CTP
• Add LINQ to SQL file (dbml)
• Can drag tables from Server Explorer
• Can drag class definitions from Solution Explorer
• Can add properties, associations, inheritance to
  the model
• Can configure insert/update/delete procedures
• Generates classes in project
• LINQ - database table DDL generation from dbml
• No relationships or constraints in generated DDL
• SQLMetal command line tool for LINQ

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EDM Tool Support

• In Visual Studio Orcas Mar CTP
• Add ADO.NET Entity Model
• Can add tables from the database
• Generates CSDL, SSDL, MSL
• Generates classes in project
• Can customize using schema-guided XML editor
• EDMGen command line tool for EDM

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Summary

• ADO.NET vNext added support for EDM
• ADO.NET provider
• Object Services
• ESQL and LINQ for Entities
• ADO.NET includes layered approach
• Rich object model
• Coexistence with familiar ADO.NET model
• with extensions for entities
• Object Services for insert/update/delete,
  transactions
• LINQ for SQL includes straightforward relational
  mapping
• Tight integration with programming languages
• LINQ for DataSets allows queries over DataSet

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Resources

• The LINQ project
• http//msdn2.microsoft.com/en-us/netframework/aa90
  4594.aspx
• ADO.NET - Making the Conceptual Level Real
• http//msdn2.microsoft.com/en-us/library/aa730866(
  VS.80).aspx
• Visual Studio Orcas Forums
• http//forums.microsoft.com/MSDN/default.aspx?Foru
  mGroupID153SiteID1
• ADO.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.net
• Paul Gielens Thoughts Service

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ADO.NET vNextThe Entity Data Model, Object
Services, and LINQ

• Bob Beauchemin
• Director of Developer Resources, SQLskills
• http//www.SQLskills.com/blogs/bobb

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