Migration loop in m:n relation with custom schema

[tomaschabada]

I have a simple many to many relation defined between the Course and Student entities

public class Student
{
    public int StudentId { get; set; }
    public string Name { get; set; }
    public List<Course> Courses { get; set; }
}

public class Course
{
    public int CourseId { get; set; }
    public string Name { get; set; }
    public List<Student> Students { get; set; }
}

I configured both entities to use my_schema database schema

 modelBuilder.Entity<Student>()
     .ToTable(nameof(Student), schema: "my_schema");

 modelBuilder.Entity<Course>()
     .ToTable(nameof(Course), schema: "my_schema");

After running the generated migration, database tables are generated as expected

Autogenerated join table has the same schema as tables it is related to. And this is causing the poblems.

Each new migration will now include strange (and useless) RenameTable operation:

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.RenameTable(
        name: "CourseStudent",
        newName: "CourseStudent",
        newSchema: "my_schema");
}

protected override void Down(MigrationBuilder migrationBuilder)
{
    migrationBuilder.RenameTable(
        name: "CourseStudent",
        schema: "my_schema",
        newName: "CourseStudent");
}

I am using EntityFramework Core version 5.0.2.


I see in generated Snapshot migration file that CourseStudent entity maps to table without specifying the schema

modelBuilder.Entity("CourseStudent", b =>
    {
        b.Property<int>("CoursesCourseId")
            .HasColumnType("int");

        b.Property<int>("StudentsStudentId")
            .HasColumnType("int");

        b.HasKey("CoursesCourseId", "StudentsStudentId");

        b.HasIndex("StudentsStudentId");

        b.ToTable("CourseStudent");
    });

With this information missing, I suppose, the tool generating new migrations is stuck in a loop where it is changing the schema for join table, but forgetting to note this somewhere (snapshot).

[ajcvickers]

/cc @AndriySvyryd @bricelam We fixed a bug where the join table was not in the same schema as the two other tables, but it looks like the snapshot might not have picked this up.

[tomaschabada]

/cc @AndriySvyryd @bricelam We fixed a bug where the join table was not in the same schema as the two other tables, but it looks like the snapshot might not have picked this up.

But the problem occurs when the join table is in the same schema as tables that it joins

[AndriySvyryd]

@tomaschabada The workaround is to specify the schema explicitly:

modelBuilder
    .Entity<Student>()
    .HasMany(l => l.Courses)
    .WithMany(r => r.Students)
    .UsingEntity(a => a.ToTable("CourseStudent", "my_schema"));

[tomaschabada]

@tomaschabada The workaround is to specify the schema explicitly:

modelBuilder
    .Entity<Student>()
    .HasMany(l => l.Courses)
    .WithMany(r => r.Students)
    .UsingEntity(a => a.ToTable("CourseStudent", "my_schema"));

I know there are workarounds. We will use one of them till the issue will be fixed