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© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
MicrosoftEntity Framework v1.1
overOracle Database
MicrosoftEntity Framework v1.1
overOracle Database
Erez Harari
Sela Technology Center
http://blogs.microsoft.co.il/blogs/erezh/
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
AgendaAgenda
• Using data in applications
• Entity Framework WH questions
• Using EF– Designing a model– Querying a model– Working with the model– Data binding support
• What else is there
• Future of EF
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Storing application dataStoring application data
• Almost all application stores data
• Data is mostly stored in relation DBs– Data stored in tables– Related data is retrievable via views– Data is stored in a normalized manner– Business-Logic sometimes “leak” to the DB
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Modeling the dataModeling the data
• Applications support a more comprehensive model for data – Object Oriented Model– Class & Object (Entity type & instance)– Properties– Inheritance– Complex data-types
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Combining the twoCombining the two
• Mapping relational to OO can be sometimes problematic– Write code to load tables into classes– Write code to load Master-Detail relations– Write code to handle Create/Update/Delete (CUD)– Apply appropriate techniques to load & persist inheritance
relations– Apply business logic to compute data after loading
• We had semi-solutions for some of these issues (Typed Datasets)
• We had 3rd party solutions – O/R (Object-Relational) Mapping tools
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
What Is Entity Framework?What Is Entity Framework?
• An O/R Mapper
• The next layer in Ado.Net
• An entity model-driven architecture
• The first step in an entity-aware data platform
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Why Use Entity Framework?Why Use Entity Framework?
• Why couple your data and your entities?
• Why write a DAL every time?
• Why learn different types of SQL syntaxes?
• Why work hard trying to handle inherited entities?
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Where can we find EF?Where can we find EF?
• Part of Visual Studio 2008 SP1
• No special project type is required
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
How does EF work?How does EF work?
DevArt tm
dotConnect for Oracle
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
DEMODEMOJust a taste
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
The Conceptual modelThe Conceptual model
• Conceptual model is based on Entity Model
• Define entity types• Group inherited types to
an entity set• Associate entities
(1:1, 1:N, N:M)
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
The Storage modelThe Storage model
• Defines different types of relational data sources:– Table– View– Stored Procedure– Native SQL
• Define functions for create / update / delete (CUD)– Use existing Stored-Procedures– Native SQL
• Import SP that retrieve Entities or Simple types
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Conceptual-Storage MappingConceptual-Storage Mapping• Map entity to storage (table, SP…)• Allow filtering source data• Support mapping single entity to multiple
storage sources• Map CUD functions to SP or SQL instead of
auto-generated queries• Support concurrency through original values• Support result binding to query output
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
DEMODEMOBuilding a model
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Querying EF - eSQLQuerying EF - eSQL
• Brand new query language
• Allow un-typed references – no compilation check
• Can leverage inheritance and collections
• Useful for dynamic query building
Employees model = new Employees();
var query = model.CreateQuery<Person>(
@"Select VALUE p
From Employees.Person as p
Where p.Age > @age");
query.Parameters.Add(new ObjectParameter("age", 30));
foreach (Person p in query)
{
Console.WriteLine(p.FirstName +
" " + p.LastName );
}
Employees model = new Employees();
var query = model.CreateQuery<Person>(
@"Select VALUE p
From Employees.Person as p
Where p.Age > @age");
query.Parameters.Add(new ObjectParameter("age", 30));
foreach (Person p in query)
{
Console.WriteLine(p.FirstName +
" " + p.LastName );
}
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Querying EF – Extension MethodsQuerying EF – Extension Methods
• Query model against EDM
• Typed references, using lambda expressions
• Compiler verified• Can return
anonymous types• A bit hard to read
Employees model = new Employees();
int age = 30;
var query = model.Person.
Where(p => p.Age > age).
Select(item => new {
FullName = item.FirstName +
" " + item.LastName });
foreach (var p in query)
{
Console.WriteLine(p.FullName);
}
Employees model = new Employees();
int age = 30;
var query = model.Person.
Where(p => p.Age > age).
Select(item => new {
FullName = item.FirstName +
" " + item.LastName });
foreach (var p in query)
{
Console.WriteLine(p.FullName);
}
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Querying EF – LINQ to EntitiesQuerying EF – LINQ to Entities
• LINQ-based syntax• Compiles as set of
extension methods• Much more readable
than extension methods
• Makes building enhanced queries a lot easier
Employees model = new Employees();
int age = 30;
var query =
from p in model.Person
where p.Age > age
select new {
FullName = p.FirstName +
" " + p.LastName};
foreach (var p in query)
{
Console.WriteLine(p.FullName);
}
Employees model = new Employees();
int age = 30;
var query =
from p in model.Person
where p.Age > age
select new {
FullName = p.FirstName +
" " + p.LastName};
foreach (var p in query)
{
Console.WriteLine(p.FullName);
}
101 LINQ Sampleshttp://tinyurl.com/62j6sb
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Querying - behind the scenesQuerying - behind the scenesfrom p in model.Person
where p.Age > age
select new {FullName = p.FirstName
+ " " + p.LastName};
from p in model.Person
where p.Age > age
select new {FullName = p.FirstName
+ " " + p.LastName};
model.Person.
Where(p => p.Age > age).
Select(p => new {FullName =
p.FirstName + " " + p.LastName });
model.Person.
Where(p => p.Age > age).
Select(p => new {FullName =
p.FirstName + " " + p.LastName });
model.CreateQuery<DbDataRecord>(
@"Select p.FirstName + "" ""
+ p.LastName as FullName
From Employees.Person as p
Where p.Age > @age");
model.CreateQuery<DbDataRecord>(
@"Select p.FirstName + "" ""
+ p.LastName as FullName
From Employees.Person as p
Where p.Age > @age");
Query tree structureQuery tree structure
SELECT 1 AS [C1], [Extent1].[FirstName] + ' ' + [Extent1].[LastName] AS [C2]
FROM [dbo].[Person] AS [Extent1]
WHERE [Extent1].[Age] > @age
SELECT 1 AS [C1], [Extent1].[FirstName] + ' ' + [Extent1].[LastName] AS [C2]
FROM [dbo].[Person] AS [Extent1]
WHERE [Extent1].[Age] > @age
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
DEMODEMOQuerying the model
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Transactions and ConcurrencyTransactions and Concurrency
• Transactions– All updates executed in .SaveChanges() are wrapped in a
transaction– Fully integrated with System.Transactions– Supports explicitly transaction usage
• Concurrency– Uses Ado.Net Optimistic concurrency checks (off by default)– Using non-default update & delete queries (Native-SQL, SP…)
allows access to current & original data
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
Working with layersWorking with layers
• EF objects can be detached from & attached to a context
• EF objects support XML serialization– XmlSerializer– DataContractSerializer
• Can be consumed through different service types:– ASP.NET Web Services– WCF Services– Ado.Net Data Services (also support JSON
serialization)
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
SummarySummary
• No more need to write DAL code• Conceptual model satisfied using EDM• CRUD operations support with no
additional code needed• Can be LINQed and queried in various
ways• Conceals, but doesn’t prevent – you
can still use your DB code (SQL / SP) if required to
© Copyright SELA Software & Education Labs Ltd. 14-18 Baruch Hirsch St. Bnei Brak 51202 Israel
ResourcesResources
• ADO.NET Entity Framework– Data platform developer center
http://msdn.microsoft.com/en-us/data/aa937723.aspx
– Ado.Net team Bloghttp://blogs.msdn.com/adonet
– Forumhttp://forums.microsoft.com/msdn/ShowForum.aspx?ForumID=533&SiteID=1
• ADO.NET Entity Framework V2 Design http://blogs.msdn.com/efdesign
• Contact Me– http://blogs.microsoft.co.il/blogs/erezh– [email protected]