Relation already exists during rake migration

Question

I have installed a blog engine to refinerycms which is working perfectly.

Now I have generated a migration with some table fields changes (of course not refinerycms or blog tables), but I'm getting an error:

== CreateBlogStructure: migrating ============================================
-- create_table("refinery_blog_posts", {:id=>true})
NOTICE: CREATE TABLE will create implicit sequence "refinery_blog_posts_id_seq1" for serial column "refinery_blog_posts.id"
rake aborted!
An error has occurred, this and all later migrations canceled:

PG::Error: ERROR: relation "refinery_blog_posts" already exists
: CREATE TABLE "refinery_blog_posts" ("id" serial primary key, "title" character varying(255), "body" text, "draft" boolean, "published_at" timestamp, "created_at" timestamp NOT NULL, "updated_at" timestamp NOT NULL)

Tasks: TOP => db:migrate
(See full trace by running task with --trace)

Answer 1

PG::Error: ERROR: relation “refinery_blog_posts” already exists

Pg is a Rails gem, the piece of code that allows communication between Rails and PostgreSQL. It relates your migrations to SQL tables, thus a relation error. So, what the error is saying is:

I'm trying to create table X, based on migration X, but table X already exists in the database.

Possible solutions:

1. Create migrations that drop those, probably old, tables.
2. Change the migration's name.

3. Login to PostgreSQL and drop the table. Something like:

   $ psql -U username databasename
   

   then

   database_name=# drop table table-name;
   

   The exact commands might be a little different though.