Change from SQLite to PostgreSQL in a fresh Rails project - ruby-on-rails

Question

I have a rails app that's databases are in SQLite (The dev and production). Since I am moving to heroku, I want to convert my database to PostgreSQL.
Anyways, I heard that the local, development, database does not need to be changed from SQLite, so I don't need to change that, however, how do I go about changing the production environment from SQLite to PostgreSQL?
Has anyone ever done this before and can help?
P.S. I'm not sure what exactly this process is called, but I've heard about migrating the database from SQLite to PostgreSQL, is that what needs to be done?

Answer 1

You can change your database.yml to this instead of using the out of the box sqlite one:
development:
adapter: postgresql
encoding: utf8
database: project_development
pool: 5
username:
password:
test: &TEST
adapter: postgresql
encoding: utf8
database: project_test
pool: 5
username:
password:
production:
adapter: postgresql
encoding: utf8
database: project_production
pool: 5
username:
password:
cucumber:
<<: *TEST

Answer 2

The steps below worked for me. It uses the taps gem, created by Heroku and mentioned in Ryan Bates's Railscast #342. There are a few steps but it worked perfectly (even dates were correctly migrated), and it was far easier than the Oracle -> DB2 or SQL Server -> Oracle migrations I have done in the past.
Note that SQLite does not have a user id or password, but the taps gem requires something. I just used the literals "user" and "password".
Create the Postgres database user for the new databases
$ createuser f3
Shall the new role be a superuser? (y/n) n
Shall the new role be allowed to create databases? (y/n) y
Shall the new role be allowed to create more new roles? (y/n) y
EDIT - Updated command below - use this instead
$ createuser f3 -d -s
Create the required databases
$ createdb -Of3 -Eutf8 f3_development
$ createdb -Of3 -Eutf8 f3_test
Update the Gemfile
gem 'sqlite3'
gem 'pg'
gem 'taps'
$ bundle
Update database.yml
#development:
# adapter: sqlite3
# database: db/development.sqlite3
# pool: 5
# timeout: 5000
development:
adapter: postgresql
encoding: unicode
database: f3_development
pool: 5
username: f3
password:
#test:
# adapter: sqlite3
# database: db/test.sqlite3
# pool: 5
# timeout: 5000
test:
adapter: postgresql
encoding: unicode
database: f3_test
pool: 5
username: f3
password:
Start the taps server on the sqlite database
$ taps server sqlite://db/development.sqlite3 user password
Migrate the data
$ taps pull postgres://f3#localhost/f3_development http://user:password#localhost:5000
Restart the Rails webserver
$ rails s
Cleanup the Gemfile
#gem 'sqlite3'
gem 'pg'
#gem 'taps'
$ bundle

Answer 3

Now its become easy with the single command
bin/rails db:system:change --to=postgresql

Answer 4

Since you're moving to heroku, you can use taps to do this:
heroku db:push
This will push your local development sqlite data to production, and heroku will automagically convert to postgres for you.
This should also work to push a production sqlite db to heroku, but it's not tested.
RAILS_ENV=production heroku db:push

Answer 5

you will also need to add the line "gem 'pg'" to your gemfile, 'pg' being the current postgres gem for Rails.

Answer 6

Simply update the config/database.yml file:
default: &default
adapter: postgresql
encoding: unicode
pool: 5
development:
<<: *default
database: projectname_development
test:
<<: *default
database: projectname_test
production:
<<: *default
database: projectname_production
username:
password:
The above is what's generated when you run:
$ rails new projectname --database=postgresql --skip-test-unit
Also add this to your Gemfile:
gem 'pg'

Answer 7

Just Update you datatbase.yml
development: &development
adapter: postgresql
database: Your_database_name
username: user_name
password: password
host: localhost
schema_search_path: public
min_messages: warning
test:
<<: *development
database: test_database_name
production:
<<: *development
database: production_db_name
We are using rails and the basic standards should be follow like DRY, Convention over Configuration etc.. so in above code we are not repeating same code again and again.

Answer 8

It's been mentioned above me, but I don't have enough reputation as a lurker to be able to upvote it. In the hopes of drawing a little more attention for Rails newbies reading this answer:
you will also need to add the line "gem 'pg'" to your gemfile, 'pg' being the current postgres gem for Rails.
^^^ This is a key piece in addition to the database.yml file described in the selected answer to migrate your Rails app to Postgres.

Answer 9

After replacing gem 'sqlite3 with gem pg in the gemfile, I kept getting the sqlite3 error when pushing to Heroku master because I forgot to commit the updated gemfile. Simply doing the following solved this:
git add .
git commit -m 'heroku push'
heroku create
git push heroku master

Answer 10

This is how I have mine setup. If you are only using MRI and not Jruby you can skip the logic in the adapter settings.
defaults: &defaults
adapter: <%= RUBY_ENGINE == 'ruby' ? 'postgresql' : 'jdbcpostgresql' %>
encoding: unicode
pool: 5
timeout: 5000
development:
database: project_development
<<: *defaults
test:
database: project_test
<<: *defaults
production:
database: project_production
<<: *defaults

Answer 11

You can try following:
sqlite3 development.db .dump | psql dbname username
or try with sqlitetopgscript:
http://trac-hacks.org/browser/sqlitetopgscript/0.10/sqlite2pg

Answer 12

A possible solution (not for heroku) it's to use yaml.db from:
http://www.railslodge.com/plugins/830-yaml-db

Answer 13

Today I had the same issue. I'm working on Rails 4.2.8. The solution was specify the pg gem version, in my case, 0.18.4.