EF migration shows empty Up() Down() methods

Question

I have a local database that is currently in it's second version and should now go to it's third version.

The code for the previous migrations was generated by another programmer so I am assuming I am doing something wrong here.

In my model there are around 30 classes, and inside the model folder there is a mapping folder and it contains the mappings for those 30 classes.

So now I added 1 new class in the same manner as those previous classes and then run the add-migration command in the Package Manager Console.

Infortunately I get an empty migration Up() and Down() method.

When I look in the database there is a __migrationHistory available with the previous 2 migrations. If I run my application now, the third migration is also added but obviously the new table is not being created because it's not in the Up() method.

What could I be doing wrong?

I think something is going wrong when scaffolding the previous migrations... It's like it can't find the new Code-First classes I have added.

This is my command:

add-migration "1.2" -verbose -ProjectName "MyEFproject"

I am assuming that the scaffolding doesn't know where to look for the new class... or is this by convention that all model classes are just expected to be in the project?

Result of add-migration:

namespace MyProject.Migrations
{
using System;
using System.Data.Entity.Migrations;

public partial class _1002 : DbMigration
{
    public override void Up()
    {
    }

    public override void Down()
    {
    }
}
}

Sample of new Model Class:

using System;
using System.Collections.Generic;

namespace MyProject.Models
{
public partial class MyTable
{

    public string SomeId { get; set; }
    public string SomeText { get; set; }


}
}

Sample of new Mapping class

using System.ComponentModel.DataAnnotations.Schema;
using System.Data.Entity.ModelConfiguration;

namespace MyProject.Models.Mapping
{
 public class MyTableMap : EntityTypeConfiguration<MyTable>
{

    public MyTableMap()
    {
        // Primary Key
        this.HasKey(t => t.SomeId);

        // Properties
        this.Property(t => t.SomeText)
            .IsRequired()
            .HasMaxLength(30);



        // Table & Column Mappings
        this.ToTable("MyTable", "database");
        this.Property(t => t.SomeId).HasColumnName("SomeId");
        this.Property(t => t.SomeText).HasColumnName("SomeText");


    }




   }
}

Thank you,

Answer 1

You need to add your table to your implementation of the DbContext class, e.g.

public class MyDatabaseEntities : DbContext {
    public virtual DbSet<MyTable> MyTable { get; set; }
}

Answer 2

While rolling back an existing EF Core Data Context back to empty, my migrations wouldn't generate until I removed the ApplicationDbContextModelSnapshot that accompanied the migrations.

This class is auto-generated and needs to align with your current migration level.

Answer 3

I was able to fix this issue by deleting a record of last migration from _MigrationHistory table. This record had been incorrectly created before I added DbSet for new model object to DbContext class. After this deletion new migration was created with correct Up() and Down() methods.

Answer 4

I had this problem because I forgot to add {get; set;} after my variable names

Answer 5

You need to add your table to your implementation of the DbContext class, e.g. While rolling back an existing EF Core Data Context back to empty, my migrations wouldn't generate until I REMOVED the ApplicationDbContextModelSnapshot that accompanied the migrations.

Answer 6

In my case, the datacontext project is a class lib project. It is different from the startup project which is asp.net mvc 5 project. Now by mistake the connection string in the startup project is pointing to a different database.

So ensure that datacontext project and startup project point to the same database. Also use the full command as mentioned in the question like the following. You can include -Force as well.

add-migration "InitialMigration" -verbose -ProjectName "MyEFproject" -Force

Answer 7

Also: Make sure any new properties you've added are public!

In my case I was doing a migration where I added fields to an existing table and was ending up with empty Up and Down methods,

I had something like this:

public bool ExistingField { get; set; }
bool NewField { get;set; }

Can you spot the difference...?

---

If you make this mistake rerun the migration with the same name (you probably will need to add the -Force parameter to scaffold it full).

PS. Always make sure your project builds fully before attempting to do any kind of EF command. If your project doesn't already build you're asking for trouble.

Answer 8

You need to add your MyTable in Dbset and your issue will be resolved:

public DbSet<MyTable> MyTables { get; set; }

Answer 9

I was getting empty migrations added when I had mistakenly related two tables using a 1-many relationship rather than a many-many (i.e. i forgot one of the navigation properties). I had a seeding file that was expecting a many-many relationship and was subsequently failing during the migration causing the migration to fail. Unfortunately there was no output that made it obvious that was the problem and it was only by using the Entity Framework Power Tools (v4 but installed in VS2015) did i visually see the incorrect relationship and realize it was probably the cause.

Answer 10

I had to Update-Database with the latest migration before the empty one appending this parameter -TargetMigration:"{your-migration-name}".

Probably it will tell you that there will be data loss from the next buggy one we tried. If you can afford it append -Force to it.

Then I tried to add my new Add-Migration and it wasn't empty.

Final thing that you may need to do if above is throwing exception is to go SQL Server Management Studio and delete the last Automatic migration and try to add it again.

Answer 11

if new tables added to Context just remove new table in "Migration/ExampleContextModelSnapshot"

Answer 12

I had the same issue on EFcore. When renaming Phone -> mobile, the migration came up empty.

My DbContext :

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
      modelBuilder.Entity<MyUser>()
            .Property(c => c.Mobile)
            .HasColumnName("phone");
   }

Problem was using .HasColumnName("phone") was overriding the actual property name so EF probably couldn't see any change. Changing string value made it work.

Answer 13

I had this exact issue after I wanted to add an extra column to my database. Because my data would not seed unless the tables were empty, I deleted all the tables and the migrations to recreate the tables. When I tried to migrate, the migration had empty up and down methods.

I solved this by deleting the snapshot file as this was creating the issue. So I deleted all the migrations and the snapshot file, added the migration again and ran update database. The tables and migrations were successfully updated with my new column.

A better way to do this though is to run the down method and drop the tables like that if you are working on test data. Obviously this is bad in the real world to drop tables.

Answer 14

To me the problem was that Id property that should correspond to table id was named FeedbackId. I changed to "Id" and then Up/Down weren't empty anymore. Dunno if that can help somehow

Answer 15

If your project is small, i.e. you do not have too many migrations yet, you can delete all from your Migration folder. After that, add the migrations again.

Answer 16

I think this also happens when u try to do migration without any changes in the models. eg when you do migration one and succeed, when u try to do migration2 without doing any changes in any of the models, it will create empty UP and Down.

Answer 17

From the perspective of a complete Entity Framework (Core) beginner:

1. Create your class which will become your table
   1. You can have subclasses with many-to-many or one-to-one relationships.
   2. In step 3 you see the context where both properties have a one-to-one relationship.
2. Ensure you have one DbContext
   1. If you have more than one DbContext you need to specify which context you want to add the migration to with the -Context parameter.
3. Add your class to your DbContext as shown by @CondingIntrigue
   1. As a reference The Entity Framework Core DbSet

public class AccountContext : DbContext
{
        public DbSet<Account> Accounts { get; set; }
        public DbSet<SecretIdentity> SecretIdentity { get; set; }
}

4. Enter Add-Migration

Answer 18

In my case, I was encountering similar problems with Visual Studio Code.

I have fixed these by doing the following:

1. Check inside your ContextModelSnapshot : ModelSnapshot
2. Comment Model Entity Definition…
3. Delete your migration files related to these entity
4. Delete the migrations from the dbo.__EFMigrationsHistory table
5. Compile your solution.
6. Run the following commands:

dotnet ef migrations add migrationName -p ProjectContainer/ 
dotnet watch run 

Answer 19

Temprorary remove

protected override void OnModelCreating(ModelBuilder modelBuilder)
{
}

and then do initial create

Add-Migration InitialCreate

Answer 20

If after adding your class in the dbContext and your migration is still empty: do the following:

In your DbContextModelSnapshot class, remove every related code to that class name that you are trying to apply add-migration on. Save the DbContextModelSnapshot.cs and use the Add-Migration "Added_filename"

This work for me.

Answer 21

In my case ,I deleted Migration folder completely. As long as I didn't remove the "ApplicationDbContextModelSnapshot" and all previous migrationas it didn't work.

Answer 22

For me it was because I hadn't add Configuration files.

onModelCreating:

    protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.ApplyConfigurationsFromAssembly(typeof(AppDbContext).Assembly);
        }

and add configurations in same assembly derived from IEntityTypeConfiguration<T> where T is your model.

Answer 23

In my case the field type was

char

as the result up and down methods were empty then I replace that with string with max length annotation fixed the issue.

    [MaxLength(1)]

    public string OrganizationType { get; set; }

Migration:

 public override void Up()
    {
        AddColumn("dbo.SupplierOrganization", "OrganizationType", c => c.String(maxLength: 1));
    }
    
    public override void Down()
    {
        DropColumn("dbo.SupplierOrganization", "OrganizationType");
    }

Answer 24

I missed adding

{get;set}

After adding getter and setter, up and down methods are not empty.