InsertSelect

This is a custom gem that extends ActiveRecord to enable the expression of SQL INSERT INTO ... SELECT ... queries in a more convenient way.
It allows you to copy data from one table to another based on specified conditions using a simple and expressive syntax.

SQL example of INSERT INTO ... SELECT ...:

INSERT INTO films SELECT * FROM tmp_films WHERE date_prod < '2004-05-07';

documentation for the query:

• MySQL: https://dev.mysql.com/doc/refman/8.0/en/insert-select.html
• PostgreSQL: https://www.postgresql.org/docs/current/sql-insert.html

Installation

Add this line to your Gemfile:

gem 'insert_select'

And then execute:

bundle install

Or install it yourself as:

gem install insert_select

Usage

Copy all data from OldUser to NewUser

NewUser.insert_select_from(OldUser)

#=> INSERT INTO "new_users" SELECT "old_users".* FROM "old_users"

Filter the columns to be copied

NewUser.insert_select_from(OldUser.select(:name))

#=> INSERT INTO "new_users" ("name") SELECT "old_users"."name" FROM "old_users"

Copy data between different column names

You can specify column name mappings between tables.

AnotherUser.insert_select_from(OldUser, mapping: { old_name: :another_name })

#=> INSERT INTO "another_users" ("another_name") SELECT "old_users"."name" FROM "old_users"

Set a constant value

AnotherUser.create_with(another_constant_column: "20").insert_select_from(OldUser, mapping: { old_name: :another_name })

#=> INSERT INTO "another_users" ("another_name", "another_constant_column") SELECT "old_users"."name", "20" FROM "old_users"

Use a WHERE clause to filter the data

NewUser.insert_select_from(OldUser.where("age > ?", 20))

#=> INSERT INTO "new_users" SELECT "old_users".*, FROM "old_users" WHERE ("age" > 20)

Use the RETURNING clause (only for PostgreSQL connection)

NewUser.insert_select_from(OldUser, returning: [:id])

#=> INSERT INTO "new_users" SELECT "old_users".* FROM "old_users" RETURNING "id"

Bang method

In default, any duplicated records are skipped in the insert_select_from method. If you want to raise an error when a duplicated record is found, use the bang method.

Assume that id is a primary key. This example does not raise an ActiveRecord::RecordNotUnique exception and no record is inserted.

User.insert_select_from(User)

This example raises an ActiveRecord::RecordNotUnique exception.

User.insert_select_from!(User)

#=> ActiveRecord::RecordNotUnique (SQLite3::ConstraintException: UNIQUE constraint failed: users.id)

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/a5-stable/insert_select. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the InsertSelect project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.