Making (and verifying) the migration to PostgreSQL in Rails

Install

After installing PostgreSQL on Windows, I converted my Rails application from MySQL to PostgreSQL with the following steps:

1. Create a new database in PostgreSQL
2. Installed postgres-pr gem (Ruby driver) because the postgres gem (native driver) didn’t work. Will figure out why later on.
3. Changed the appropriate Rails config stuff in database.yml

   development:
     adapter: postgresql
     database: database_name
     username: postgres
     password: password
     host: localhost

4. I ran only my first Rails migration to test that it worked using this command: rake db:migrate VERSION=1. My first migration (001_create_heartrates.rb) creates a table in the database so it will be easy to test.

Robby explains a quick way to migrate the data as well

Test

You can test that the migration worked via 2 methods (GUI or command line)

1. Using following commands with the psql command line utility (Start Menu -> PostgreSQL -> psql to postgres):
   

   psql commmand	Description
   \?	help
   \c database_name	connect to a database (many other commands won’t work until you execute this)
   \dt	show tables (execute \c first)
   \d table_name	describes a particular table (e.g. table_name)

2. Using the pgAdmin III GUI:
   • The database table is deeply nested in the tree, I missed it at first. Go to PostgreSQL Database Server 8.2 -> Databases -> database_name -> Schemas -> public -> Tables -> table_name