One-to-Many association
The following example illustrates creation of a one-to-many association within an Entity Framework model.
The database contains the Dept and Emp tables, which have a foreign key constraint between them.
The field DEPTNO in the table Emp receives the ID value of the associated record in the Dept table.
We perform the following sequence of operations:
- create an Entity Framework model;
- add the Dept and Emp tables to the model.
As a result, we have the following model:
The association between the Dept and the Emp entities looks as follows:
In case all foreign key columns of the details table are nullable, the association will have the zero-or-one to many type, which means that the detail class navigation property referring to the master class can be NULL.