Entity Framework - Queries

1. EF Queries
Eyal Vardi
CEO E4D Solutions LTD
Microsoft MVP Visual C#
blog: www.eVardi.com

2. Agenda
LINQ to Entity EDM
Entities SQL
Conceptu
Object Services al Model
Mapping
Entity Client Provider
Storage
Model
ADO.NET Provider
 EF Architecture
 Development Approaches
 Entity Data Model (EDM)
 Object Services
 Querying & Loading Entities
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3. EF Architecture
from c in db.Customers
where c.City == "London" Application
select
new { c.Name, c.Phone }
LINQ Query Objects SubmitChanges()
Services:
Entity Framework - Change tracking
EDMX - Concurrency control
- Object identity
ADO.NET Provider
SQL Query Rows SQL or
Stored
Procs
select Name, Phone
from customers
where city = 'London'
SQLServer
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

4. EF Architecture
LINQ to Entities Entity SQL EDM
Conceptual
Object Services Model
Mapping
Entity Client Provider
Storage
ADO.NET Provider Model
SQLServer
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

5. LINQ to Entity EDM
Entities SQL
Conceptu
Object Services al Model
Mapping
Entity Client Provider
Storage
Model
ADO.NET Provider
Querying & Loading Entities
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

6. Entity SQL & LINQ to Entities
 LINQ to Entities - The LINQ dialect that
enables typed queries against the model.
 Entity SQL - The second way of querying the
object model.
 Entity SQL is string-based.
 Can be used to retrieve data at low level, directly using the
Entity Client.
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

7. Entity SQL Queries
 The SqlQuery method on DbSet allows a raw
SQL query to be written that will return entity
instances.
 The returned objects will be tracked by the context just as
they would be if there were returned by a LINQ query.
 The query is not executed until the results are enumerated
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

8. SQL Queries for none Entity Types
 The results returned from SqlQuery on
Database will never be tracked by the context
even if the objects are instances of an entity
type.
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il

9. Stored Procedures
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10. SP Sample
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11. Updating Data with SP
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12. Functions
© 2010 E4D LTD. All rights reserved. Tel: 054-5-767-300, Email: Eyal@E4D.co.il