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Entity Framework

  • it is an open source object-relational mapping framework for ADO.NET
    • ADO.NET provides consistent access to data sources
      • eg SQL Server and XML
      • and to data sources exposed through OLE DB and ODBC

How to use Entity Franework in visual studio​

  • open NuGet Package Manager Console
  • key in all of the following commands in the NuGet Package Manager Console

Enable migrations (required for first times)​

  • this will create the default database files in the "App_Data" folder

    enable-migrations

Add migration​

  • use to create migration
  • name of migration is dependent on the domain model
  • first time migration usually name as "InitialModel"

    add-migration MigrationFileName

  • if required to overwrite, use the -force

    add-migration ModelName -force

  • this can be used to create migration file and then manually modify the migration file
  • the following will be auto generated
using System;
using System.Data.Entity.Migrations;

public partial class MigrationFileName : DbMigration
{
  public override void Up()  // use to update db based on code written
  {}

  public override void Down()  // use to revert our migrations
  {}
}
  • write sql code in either the Up or Down method
Sql("INSERT INTO ModelName (Id, PropertyName1, PropertyName2) VALUES (numberValue, numberValue, numberValue)");

Update database​

  • after adding migration, database has yet to be updated
  • this will update the database files stored in the "App_Data" folder

    update-database