There is already an object named 'schema_migrations' in the database

rubyonrails-talk
1

I've created a table in a SQL Server database using a migration, successfully. I've tried to change the name of a column in the table and got the error message above when running 'rake db:migrate'. Previously I have developed using MySQL and Sqlite and migrations have worked successfully. This is an error I have not seen before. Has anybody seen this and worked around it?

thnx Martin

2

It sounds like you edited an existing migration -- if so, don't :slight_smile:

Create a new migration to change the column, or drop the entire DB and start from scratch.

HTH,

3

Hassan, Thanks for the reply. No, I didn't edit an existing migration - I created a new one for the rename.

I understand what you are saying about dropping the table (not the entire db surely :-0). While that would work, I wouldn't get to understand what the problem is!!

Martin

4

No, I didn't edit an existing migration - I created a new one for the rename.

It sounds like your second migration is trying to create the schema table which already exists.

Maybe you could post your migrations, or at least the failing one?

I understand what you are saying about dropping the table (not the entire db surely :-0).

Yes, the whole DB -- if you're wanting to fix a bad migration and run it all from the beginning. That's not a bad thing early in a project.

5

Yes, I agree that the second migration seems to be trying to re-create the schema table.

The database is a legacy SQL Server db with over 100 tables already in existence. I've noticed that db/schema.rb contains no information re the table that was built, hence rake trying to re-create the schema_migrations table. The first migration created a searches table: class CreateSearches < ActiveRecord::Migration   def self.up     create_table :searches do |t|       t.date :start       t.date :end       t.integer :team_id       t.integer :match_id       t.integer :innings_id       t.integer :over_id       t.integer :ball_id       t.integer :match_session_id       t.integer :bowler_id       t.integer :delivery_type_id       t.integer :extra_type_id       t.integer :appeal_id       t.integer :shot_type_id       t.integer :runs_id       t.integer :batter_id       t.integer :umpire_id       t.integer :validity_id       t.integer :decison_id       t.integer :height_id       t.integer :extra_runs_id       t.timestamps     end   end

  def self.down     drop_table :searches   end end and the second migration tried to rename one of the columns:

class RenameTeamId < ActiveRecord::Migration   def self.up     rename_column :searches, :team_id, :home_team_id   end

  def self.down     rename_column :searches, :home_team_id, :team_id   end end

Dropping the whole DB is really not an option. Martin

6

The database is a legacy SQL Server db with over 100 tables already in existence. I've noticed that db/schema.rb contains no information re the table that was built, hence rake trying to re-create the schema_migrations table.

The first migration created a searches table:

And that was created with no errors? I assume you've looked in the SQL Server error log(s)?

and the second migration tried to rename one of the columns:

So what does schema_migrations contain at this point?

Dropping the whole DB is really not an option.

Got it. But if I were you, I'd create a new temporary rails projects, just using sqlite3,. and try running your migrations there as a test. If they work there, then there's something peculiar to your original config.

Caveat: I know zero about MS SQL Server so...