Using Entity Framework 6 with Multiple DB Schemas but using One DBContext

问题

I have an application using EF as ORM. The database used to have one schema, dbo and everything was working fine. I recently organized my tables into 4 different schemas. Some tables of one schema have dependencies on tables that reside on a different schema. All seems to be valid on the SQL side.

On the app side all db interactions through EF are not working anymore. The code compiles, the schemas are visible in the solution, the model mappings point to the right schemas, but once I try to insert a row to a table it does not work.

I have seen a few posts about using multiple schemas will require using multiple DBContexts but I would rather use one DBContext. All my schemas have the same owner dbo and I do not see a reason of using multiple DBContexts.

Does anyone know if there is a way to achieve this?

回答1:

You can map each table to its own schema by fluent mapping only. In your DbContext subtype you should override OnModelCreating (if you haven't done so already) and add statements like this:

modelBuilder.Entity<Department>()  
    .ToTable("t_Department", "school");

Entities that you don't map like this explicitly will be placed in the default dbo schema, or you can provide your own default by

modelBuilder.HasDefaultSchema("sales");

(summarized from here)

回答2:

In addition to the responce of Gert Arnold, you can also use Table attribute in your entity:

using System.ComponentModel.DataAnnotations.Schema;

[Table("t_Department", Schema = "school")]
public class Department
{
    public int Id { get; set; }

    public string Name { get; set; }
}

回答3:

@GertArnold is spot on with his answer. However for pure syntactic candy you can also do this via a convention to pull the schema from the namespace of your models. We found this useful dealing with multiple schemas

modelBuilder.Types().Configure(e => {
        var schema = e.ClrType.Namespace.Split('.').Last().ToLower();
        var name = entity.ClrType.Name;
        return entity.ToTable(name, schema);
});

the above will take the final component of the namespace and use it as the schema name. This avoids the need for customising the table binding for every entity.

回答4:

ok, you put schema o class header etc but where you define that schema? for example:

[Table("Test", Schema = "test1")]
public class Test
{
    public int Id { get; set; }
}

[Table("Test2", Schema = "test2")]
public class Test2
{
    public int Id { get; set; }
}

but where to put test1 and test2? different DbContexts or where?

回答5:

In my case, it's possibly that I use DB First to generate my EDMX file, so it doesn't invoke OnModelCreating method.

I finally remove all store:Schema="YourSchema" and Schema="YourSchema" in EDMX file, and I do it by write a bat file with powershell command as below, and execute the bat in the Projec Pre-Build Event:

powershell -Command "$varStr='store:Schema=""abcd""""'; $filePath='%~dp0SomeFolder\SomeFile.txt'; (gc $filePath) -replace $varStr, '' | Out-File $filePath"

来源：https://stackoverflow.com/questions/36576932/using-entity-framework-6-with-multiple-db-schemas-but-using-one-dbcontext

标签

entity-framework

dbcontext

db-schema