Wednesday, 24 April 2013

Scaler and Navigation Properties in ADO.NET Entity Framework


Scaler and Navigation Properties in ADO.NET Entity Framework

Entities in ADO.NET Entity Framework can have two types of properties, Scalar properties and Navigation properties. 

Scalar Properties: Scalar properties are properties whose actual values are contained in the entity. 
Navigation Properties: Navigation properties are pointers to other related entities. Basically it is equivalent to a foreign key relationship in a database. 

Example of Scaler and Navigation Properties:

I will take an example here to make my defination more clear. Suppose there is Student table in database which has columns like StudentID, StudentName and StandardID. There is another table Standard which has StandardID, StandardName columns. Here StandardID is the forieng key. Now lets create and EDMX from these two tables. EDMX will have two entities Student and Standard which will look like following:

EDMX Entity of Student

Student              --Entity Name
-----------
StudentID          --Scaler Property
StudentName   --Scaler Property
StandardID       --Scaler Property
-----------
Standard           --Navigation Property

EDMX Entity of Standard

Standard               --Entity Name
-----------
StandardID           --Scaler Property
StandardName    --Scaler Property
-----------

Student entity has scalar properties e.g. StudentId, StudentName, StandardID. These correspond with the Student table columns.  

The Student has Standard property as navigation property that will enable application to navigate from a Student to related Standard entity. 

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