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Asked: 2020-10-29 08:36:03 +0800 CST 2020-10-29 08:36:03 +0800 CST

How to Revert from .NET Core to .NET 4.6 - Entity Framework 6

  • 772

A Web API project needs to be backported from Core 2.2 to .Net framework 4.6 and is developed in codefirst ; in the class of dbContext there is OnModelCreatingsome initial data but an error appears in the "hasData" line:

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    base.OnModelCreating(modelBuilder);
    modelBuilder.Entity<Generador>().**HasData**(
        new Generador { Nombre = "xm324", Capacidad = 1000000 },
        new Generador { Nombre = "Bee344", Capacidad = 3000000 },
        new Generador { Nombre = "DCM445", Capacidad = 5000000 }
        );
}

How is .NET Core 2.2 different from 4.6?

c#

2 Answers

  1. Best Answer

    To insert data into your DB with EF 6 and .NET 4.6, you must follow these steps:

    1. In the configuration file Configuration.csinside the Migrations directory , you must override the method Seed()as follows:

      internal sealed class Configuration : 
DbMigrationsConfiguration<ApplicationDbContext>
{
  public Configuration()
  {
      AutomaticMigrationsEnabled = false;
  }

  protected override void Seed(ApplicationDbContext context)
  {
    context.Generador.AddOrUpdate(x => x.Id,
        new Generador { Nombre = "xm324", Capacidad = 1000000 },
        new Generador { Nombre = "Bee344", Capacidad = 3000000 },
        new Generador { Nombre = "DCM445", Capacidad = 5000000 }
    );
  }
}

    2. Next, create a migration to update the new data in the database.

    PM> Add-Migration MigracionUpdate

    1. Finally update the DB.

    PM> Update-Database

    UPDATE : Keep in mind that what the extender method AddOrUpdate()will do is insert (Insert) or update (Update) the records in the DB, each time an EF6 Update-Database is performed. So every time a migration is done , it will check if the logs exist, and if not, it will create them. In the event that the records already exist in the DB, it will only modify them if they are different.

    • 2

  2. The HasData option is apparently only available in .Net Core starting from version 2.1, to plant data (Seed Data) in non-core versions of entity framework use the seed method or you can specify them in your migrations, create a migration specify to popular your tables:

     protected override void Up(MigrationBuilder mb)
 {
  mb.Sql("INSERT INTO Generador (Nombre, Capacidad) VALUES ('xm324',1000000 )");
  //Mas instrucciones
  }
    • 0