Guide to Entity Framework with

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Let's explain each of these layers in detail:
• 
The Conceptual Layer or the C-Space Layer is responsible for defining 
the entities and their relationships. It defines your business objects and 
their relationships in XML files. The C-Space is modeled using CSDL and 
comprises EntityContainer, EntitySets, AssociationSets, AssociationTypes, 
EntityTypes, and functions. You can query this layer using Entity SQL or 
ESQL (EntityConnection, EntityCommand, and EntityDataReader).
• 
The C-S Mapping Layer is responsible for mapping the conceptual and the 
logical layers. That is, it maps the business objects and the relationships 
defined in the conceptual layer with the tables and relationships defined 
in the Logical layer. It is a mapping system created in XML, which links 
or maps the conceptual and the Logical layers. The C-S Mapping Layer is 
modeled using Mapping Storage Layer or the MSL.
• 
The Logical or the Storage Layer (also called the S-Space) represents the 
schema of the underlying database. This comprises tables, stored procedures, 
views, and functions. It is modeled using SSDL and queried using the 
database providers. A database provider is an API to connect to and perform 
CRUD operations against a database. As an example, if the database in use 
is SQL Server, the ADO.NET data provider for SQL Server will be used. 
Hence, we use SQLConnection, SQLCommand, SQLDataReader, and 
SQLDataAdapter using T-SQL or PL-SQL if our data store is a SQL database.

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Chapter 1
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Here is what a typical EDM looks like:
Designation
Employee
ProvidentFund
Salary
Department
Properties
Properties
Properties
Properties
Properties
Properties
Properties
Properties
Properties
Properties
Employees
Employees
Employee
Employee
PFID
EmployeeID
PFAmount
SalaryID
EmployeeID
Basic
Allowance
PFID
Tax
GrossSalary
NetSalary
EmployeeID
FirstName
LastName
Address
Phone
DepartmentID
JoiningDate
LeavingDate
DesignationID
PFID
Department
Designation
ProvidentFunds
Salaries
DepartmentID
DepartmentName
DepartmentID
DepartmentName
1
*
1
*
1
*
1
*
An ADO.NET Entity Data Model at a glance