entity framework execute SQL before migrations

问题:

I am working on an existing project that uses Entity-Framework 6 with code-first. I have a need to run some SQL before the migrations run.

I have a DbMigrationsConfiguration class with a seed method, but seed runs after the migrations.

I think it will work if I run my SQL in the constructor but I can't get a reference to the context.

Does anyone know how to do this?

回答1:

You could use the 'Sql' method within the desired migration class.

public partial class OneOfYourMigrations : DbMigration 
{ 
    public override void Up() 
    { 
        //EF generated migration code here such as
        //CreateTable or AddColumn etc...
        //Now run your custom sql - here I'm doing an update to an existing column
        Sql("UPDATE dbo.YourTable SET Column1 = 'VALUE1' "); 
    } 

    public override void Down() 
    { 
        //EF generated code to rollback
    } 
}     

So the steps are;

• Generate migration class using Add-Migration
• Alter the class using code similar to above
• Run the migration using Update-Database