Entity Framework 4.3 migrations on existing "Shared" database

Question

We have a huge database with different database schemas for different web applications. For example: WebApp1 uses Schema1.Tables. WebApp2 uses Schema2.Tables and so on.

Now, I am developing a new web application (WepApp3) which will use Entity Framework 4.3.1. WebApp3 should only be concerned with Schema3 and use only those database object which are part of Schema3. If i create some Entities in WepApp3, How do i migrate these entities to database as schema3.tables? Do i still need to do Initial Migration?

Please help.

Answer 1

It seems to WORK. I started with an existing database. created an mvc app (app1) with couple of models. I then created a schema for this app in database. I specified schema for the models as per your comment. Then I used the power of code based migration script to update the database. Migration script created 2 tables under the new schema without corrupting existing stuff. I noticed EF created __MigrationHistory table with a row with change info. Then i created another app, a new schema and repeated the migration process with a little tweak in migration script. The script had code to re-create 2 tables of app1. i deleted that code from script. EF then successfully created new tables under new schema and also created new row in __MigrationHistory table with info about new changes. All existing stuff remain unchanged including data.

Answer 2

I don't think it's possible to have multiple EF models in the same database. EF shouldn't try to touch tables that are nothing to do with its model, but if you wanted to add another EF app to the same database you'd run into trouble because they'd try to share the same MetaData tables.

When generating new models using code-first, you can specify which schema they should be part in the DbContext:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    modelBuilder.Entity<MyEntity>().ToTable("MyEntity", "Schema3");
}

Is it an option to migrate your schemas out into different databases if there are no shared apps?