Configure One To Many Relationship in MVC and EntityFrameWork Code First, Code Migration Approach

Learn and build web application using MVC and Entity framework code first, code migration approach

Video: https://www.youtube.com/watch?v=GanjklfebEc&index=1&list=PLdmgFSerzv2Kl00tz0qY-jxDPnPowpRaT

Learn MVC and Entity framework code first, code migration approach using sample demo application

Video: https://www.youtube.com/watch?v=OhJtxRvgeK0&list=PLdmgFSerzv2Lhj5dFrD75sz26qGdxpo8Z

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Overview

Relationships scenario(One To Many Relationship)

Video: https://www.youtube.com/watch?v=9qyRIW0FTZ8

• Course can have multiple Students
• Student can select only one course

  

• Course model contains the following properties defined.

  

• Open the student model and add the Navigational property for course.
• Configure the Foreign key by adding CourseId (Primary key of the Course class model) entity in the Student class.
• 1 to 1 relationship (1 Student can select 1 Course) and
• 1 to Many relationship ( 1 Course can have Many Students) is established.

  

• Generate migration file by executing the command "ADD-Migration" in the package manager console for configuring Foreign Key in Student table in the database side.
• Script gets generated in migration file.

  

• Once the script got generated, update the database.

  

  Note: Establishing foreign key relationship to the model with student table containing data will generate the foreign key constraint error since Course Id is defined not nullable.

  

• Once after executing the "Update-database" command in Package manger console, script present in the "up method " of the configuration file will be executed in the SQL Server and Foreign Key will be established to the Course table.

  

• Add the required changes in the create action method in the Student Controller.

  

• Create a dropdownlist in the viewpage for selecting the course for a particular student in the "create.cshtml" view page.

  

• Modify the Edit Action method and Edit.cshtml viewpage:

  

• Add the Dropdownlist to display and provide options to choose the course in the dropdown.

  

• Run the application and test it.
• DropdownList for selecting the course will be present and
• 1 to Many Relationship and ForeignKey is configured and established.