![]() Notice the CategoryId dropdown in above create view of SubCategory, this is coming because of foreign key relationship specified in the SubCateogry model. The foreign key, defined in part 1 of this book (see chapter 2, section 2.1.3), which holds the principal key value(s) of the database row it is linked to (or could be null). For Example, the Employee working in a Department is a relationship. We use the Foreign Key to define the relationship between two tables in the database. Here are the classes that I'm using to create the tables. In this tutorial learn to use the ForeignKey attribute in Entity Framework to configure the Foreign Key Property. ![]() I have mapped the second table CDT DEF in CDT ABC, however while verifying the Data Store, I am. I am trying to create foreign keys with Entity Framework using data annotations, but according to the migration information, EF will create all the required columns, but the one with the foreign key is not showing up like I want to, plus is creating an extra normal column. The benefit of this is that while scaffolding Controller and Views for SubCategory, the SubCategory create view will automatically show a dropdown of Categories to select as shown below. In the second table DEF I have provide the reference as ABC.ID. Taking the hierarchical example of the Employee. As this is the foreign key from the primary key table Category so we have specified the ForeignKey attribute to the primary key Category model property by specifying the name of the property as parameter. The ForeignKey Data Annotation allows you to define the foreign key for a navigational property in the class. Notice the CategoryId property of the SubCategory model. I have a special case with legacy data where a FK property is required but may or may not reference a record in the relationship. Now create appropriate model in the ASP.NET MVC project for the respective database tables.Ĭategory.cs public class Category The principal end of this association must be explicitly configured using either the relationship fluent API or data annotations. Setting Foreign Key attributes (annotations) with the Required attribute will also enforce EF required navigation properties EVEN WHEN the FK property is nullable.
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