Entity Framework Migrations renaming tables and columns

Question

I renamed a a couple entities and their navigation properties and generated a new Migration in EF 5. As is usual with renames in EF migrations, by default it was going to drop objects and recreate them. That isn't what I wanted so I pretty much had to build the migration file from scratch.

    public override void Up()
    {
        DropForeignKey("dbo.ReportSectionGroups", "Report_Id", "dbo.Reports");
        DropForeignKey("dbo.ReportSections", "Group_Id", "dbo.ReportSectionGroups");
        DropForeignKey("dbo.Editables", "Section_Id", "dbo.ReportSections");
        DropIndex("dbo.ReportSectionGroups", new[] { "Report_Id" });
        DropIndex("dbo.ReportSections", new[] { "Group_Id" });
        DropIndex("dbo.Editables", new[] { "Section_Id" });

        RenameTable("dbo.ReportSections", "dbo.ReportPages");
        RenameTable("dbo.ReportSectionGroups", "dbo.ReportSections");
        RenameColumn("dbo.ReportPages", "Group_Id", "Section_Id");

        AddForeignKey("dbo.ReportSections", "Report_Id", "dbo.Reports", "Id");
        AddForeignKey("dbo.ReportPages", "Section_Id", "dbo.ReportSections", "Id");
        AddForeignKey("dbo.Editables", "Page_Id", "dbo.ReportPages", "Id");
        CreateIndex("dbo.ReportSections", "Report_Id");
        CreateIndex("dbo.ReportPages", "Section_Id");
        CreateIndex("dbo.Editables", "Page_Id");
    }

    public override void Down()
    {
        DropIndex("dbo.Editables", "Page_Id");
        DropIndex("dbo.ReportPages", "Section_Id");
        DropIndex("dbo.ReportSections", "Report_Id");
        DropForeignKey("dbo.Editables", "Page_Id", "dbo.ReportPages");
        DropForeignKey("dbo.ReportPages", "Section_Id", "dbo.ReportSections");
        DropForeignKey("dbo.ReportSections", "Report_Id", "dbo.Reports");

        RenameColumn("dbo.ReportPages", "Section_Id", "Group_Id");
        RenameTable("dbo.ReportSections", "dbo.ReportSectionGroups");
        RenameTable("dbo.ReportPages", "dbo.ReportSections");

        CreateIndex("dbo.Editables", "Section_Id");
        CreateIndex("dbo.ReportSections", "Group_Id");
        CreateIndex("dbo.ReportSectionGroups", "Report_Id");
        AddForeignKey("dbo.Editables", "Section_Id", "dbo.ReportSections", "Id");
        AddForeignKey("dbo.ReportSections", "Group_Id", "dbo.ReportSectionGroups", "Id");
        AddForeignKey("dbo.ReportSectionGroups", "Report_Id", "dbo.Reports", "Id");
    }

All I'm trying to do is rename dbo.ReportSections to dbo.ReportPages and then dbo.ReportSectionGroups to dbo.ReportSections. Then I need to rename the foreign key column on dbo.ReportPages from Group_Id to Section_Id.

I am dropping the foreign keys and indexes linking the tables together, then I am renaming the tables and the foreign key column, then I'm adding the indexes and foreign keys again. I assumed this was going to work but I am getting a SQL error.

Msg 15248, Level 11, State 1, Procedure sp_rename, Line 215 Either the parameter @objname is ambiguous or the claimed @objtype (COLUMN) is wrong. Msg 4902, Level 16, State 1, Line 10 Cannot find the object "dbo.ReportSections" because it does not exist or you do not have permissions.

I'm not having an easy time figuring out what is wrong here. Any insight would be tremendously helpful.

Answer 1

This issue was happening with me because I set builder.ToTable("hardCodedTableName"); in my table configuration file. When you use this ToTable method EF overrides the name chosen in the DbSet. That's why my tables were never renamed (because they still had this hardcoded old name). Very stupid, but maybe it was the case of others as well..

Answer 2

Hossein Narimani Rad answer is really nice and straightforward. But it doesn't work for the EF core. because dotnet ef migration add doesn't have the --force option.

You have to do it this way.

1- add [Column("NewColumnName")]

2- create a migration dotnet ef migration add RenameSomeColumn

3- copy all the code in RenameSomeColumn.cs

4- remove migration dotnet ef migrations remove

5- remove [Column("NewColumnName")] and rename Property to NewColumnName

6- again create migration dotnet ef migration add RenameSomeColumn

7- past all the code copied from removed migration into new RenameSomeColumn.cs

Answer 3

In EF Core, I use the following statements to rename tables and columns:

As for renaming tables:

    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameTable(
            name: "OldTableName",
            schema: "dbo",
            newName: "NewTableName",
            newSchema: "dbo");
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameTable(
            name: "NewTableName",
            schema: "dbo",
            newName: "OldTableName",
            newSchema: "dbo");
    }

As for renaming columns:

    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameColumn(
            name: "OldColumnName",
            table: "TableName",
            newName: "NewColumnName",
            schema: "dbo");
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.RenameColumn(
            name: "NewColumnName",
            table: "TableName",
            newName: "OldColumnName",
            schema: "dbo");
    }

Answer 4

For EF Core migrationBuilder.RenameColumn usually works fine but sometimes you have to handle indexes as well.

migrationBuilder.RenameColumn(name: "Identifier", table: "Questions", newName: "ChangedIdentifier", schema: "dbo");

Example error message when updating database:

Microsoft.Data.SqlClient.SqlException (0x80131904): The index 'IX_Questions_Identifier' is dependent on column 'Identifier'.

The index 'IX_Questions_Identifier' is dependent on column 'Identifier'.

RENAME COLUMN Identifier failed because one or more objects access this column.

In this case you have to do the rename like this:

migrationBuilder.DropIndex(
    name: "IX_Questions_Identifier",
    table: "Questions");

migrationBuilder.RenameColumn(name: "Identifier", table: "Questions", newName: "ChangedIdentifier", schema: "dbo");

migrationBuilder.CreateIndex(
    name: "IX_Questions_ChangedIdentifier",
    table: "Questions",
    column: "ChangedIdentifier",
    unique: true,
    filter: "[ChangedIdentifier] IS NOT NULL");

Answer 5

In ef core, you can change the migration that was created after add migration. And then do update-database. A sample has given below:

protected override void Up(MigrationBuilder migrationBuilder)
{
    migrationBuilder.RenameColumn(name: "Type", table: "Users", newName: "Discriminator", schema: "dbo");
}

protected override void Down(MigrationBuilder migrationBuilder)
{            
    migrationBuilder.RenameColumn(name: "Discriminator", table: "Users", newName: "Type", schema: "dbo");
}

Answer 6

If you don't like writing/changing the required code in the Migration class manually, you can follow a two-step approach which automatically make the RenameColumn code which is required:

Step One Use the ColumnAttribute to introduce the new column name and then add-migration (e.g. Add-Migration ColumnChanged)

public class ReportPages
{
    [Column("Section_Id")]                 //Section_Id
    public int Group_Id{get;set}
}

Step-Two change the property name and again apply to same migration (e.g. Add-Migration ColumnChanged -force) in the Package Manager Console

public class ReportPages
{
    [Column("Section_Id")]                 //Section_Id
    public int Section_Id{get;set}
}

If you look at the Migration class you can see the automatically code generated is RenameColumn.

Answer 7

Table names and column names can be specified as part of the mapping of DbContext. Then there is no need to do it in migrations.

public class MyContext : DbContext
{
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Restaurant>()
            .HasMany(p => p.Cuisines)
            .WithMany(r => r.Restaurants)
            .Map(mc =>
            {
                mc.MapLeftKey("RestaurantId");
                mc.MapRightKey("CuisineId");
                mc.ToTable("RestaurantCuisines");
            });
     }
}

Answer 8

Nevermind. I was making this way more complicated than it really needed to be.

This was all that I needed. The rename methods just generate a call to the sp_rename system stored procedure and I guess that took care of everything, including the foreign keys with the new column name.

public override void Up()
{
    RenameTable("ReportSections", "ReportPages");
    RenameTable("ReportSectionGroups", "ReportSections");
    RenameColumn("ReportPages", "Group_Id", "Section_Id");
}

public override void Down()
{
    RenameColumn("ReportPages", "Section_Id", "Group_Id");
    RenameTable("ReportSections", "ReportSectionGroups");
    RenameTable("ReportPages", "ReportSections");
}

Answer 9

To expand a bit on Hossein Narimani Rad's answer, you can rename both a table and columns using System.ComponentModel.DataAnnotations.Schema.TableAttribute and System.ComponentModel.DataAnnotations.Schema.ColumnAttribute respectively.

This has a couple benefits:

1. Not only will this create the the name migrations automatically, but
2. it will also deliciously delete any foreign keys and recreate them against the new table and column names, giving the foreign keys and constaints proper names.
3. All this without losing any table data

For example, adding [Table("Staffs")]:

[Table("Staffs")]
public class AccountUser
{
    public long Id { get; set; }

    public long AccountId { get; set; }

    public string ApplicationUserId { get; set; }

    public virtual Account Account { get; set; }

    public virtual ApplicationUser User { get; set; }
}

Will generate the migration:

    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropForeignKey(
            name: "FK_AccountUsers_Accounts_AccountId",
            table: "AccountUsers");

        migrationBuilder.DropForeignKey(
            name: "FK_AccountUsers_AspNetUsers_ApplicationUserId",
            table: "AccountUsers");

        migrationBuilder.DropPrimaryKey(
            name: "PK_AccountUsers",
            table: "AccountUsers");

        migrationBuilder.RenameTable(
            name: "AccountUsers",
            newName: "Staffs");

        migrationBuilder.RenameIndex(
            name: "IX_AccountUsers_ApplicationUserId",
            table: "Staffs",
            newName: "IX_Staffs_ApplicationUserId");

        migrationBuilder.RenameIndex(
            name: "IX_AccountUsers_AccountId",
            table: "Staffs",
            newName: "IX_Staffs_AccountId");

        migrationBuilder.AddPrimaryKey(
            name: "PK_Staffs",
            table: "Staffs",
            column: "Id");

        migrationBuilder.AddForeignKey(
            name: "FK_Staffs_Accounts_AccountId",
            table: "Staffs",
            column: "AccountId",
            principalTable: "Accounts",
            principalColumn: "Id",
            onDelete: ReferentialAction.Cascade);

        migrationBuilder.AddForeignKey(
            name: "FK_Staffs_AspNetUsers_ApplicationUserId",
            table: "Staffs",
            column: "ApplicationUserId",
            principalTable: "AspNetUsers",
            principalColumn: "Id",
            onDelete: ReferentialAction.Restrict);
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropForeignKey(
            name: "FK_Staffs_Accounts_AccountId",
            table: "Staffs");

        migrationBuilder.DropForeignKey(
            name: "FK_Staffs_AspNetUsers_ApplicationUserId",
            table: "Staffs");

        migrationBuilder.DropPrimaryKey(
            name: "PK_Staffs",
            table: "Staffs");

        migrationBuilder.RenameTable(
            name: "Staffs",
            newName: "AccountUsers");

        migrationBuilder.RenameIndex(
            name: "IX_Staffs_ApplicationUserId",
            table: "AccountUsers",
            newName: "IX_AccountUsers_ApplicationUserId");

        migrationBuilder.RenameIndex(
            name: "IX_Staffs_AccountId",
            table: "AccountUsers",
            newName: "IX_AccountUsers_AccountId");

        migrationBuilder.AddPrimaryKey(
            name: "PK_AccountUsers",
            table: "AccountUsers",
            column: "Id");

        migrationBuilder.AddForeignKey(
            name: "FK_AccountUsers_Accounts_AccountId",
            table: "AccountUsers",
            column: "AccountId",
            principalTable: "Accounts",
            principalColumn: "Id",
            onDelete: ReferentialAction.Cascade);

        migrationBuilder.AddForeignKey(
            name: "FK_AccountUsers_AspNetUsers_ApplicationUserId",
            table: "AccountUsers",
            column: "ApplicationUserId",
            principalTable: "AspNetUsers",
            principalColumn: "Id",
            onDelete: ReferentialAction.Restrict);
    }

Answer 10

I just tried the same in EF6 (code first entity rename). I simply renamed the class and added a migration using the package manager console and voila, a migration using RenameTable(...) was automatically generated for me. I have to admit that I made sure the only change to the entity was renaming it so no new columns or renamed columns so I cannot be certain if this is an EF6 thing or just that EF was (always) able to detect such simple migrations.