Eric Nelson
Developer & Platform Group
Microsoft Ltd
eric.nelson@microsoft.com
http://geekswithblogs.net/IUpdateable
http://twitter.com/ericnel

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

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!

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!

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

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

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

{ Simple Walkthough }

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

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

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

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

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

{ A look at mapping }

2 1 The ORM
- optional
Object Services
3
Entity Client

Familiar ADO.NET object model:
EntityCommand
EntityConnection
EntityDataReader
EntityParameter
EntityTransaction
Text-based results
Read-only
Uses Entity SQL

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

{ Consuming an EDM}

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

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!

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

Foreign 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();

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

Entities do their own change tracking
regardless of which tier changes are made on
Somewhere between DTOs and DataSets

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!!!

Complex Types
Map a new type to many types
Adds designer support

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());

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

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

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...

Improved N-Tier API
More LINQ query operators
More SQL generation optimizations
Inline functions in ESQL
Readonly mapping

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

http://blogs.msdn.com/efdesign
Entity Framework v2
http://geekswithblogs.net/IUpdateable
Slides
Sessions Thursday on
SQL Data Services 9:30am
Windows Azure 2:00pm

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Driven by Reporting Services team + others
Query 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\" >