postgres_ext: Adding Postgres data types to Rails
Over the past few weeks, I have been working on a new gem which adds support to Rail’s ActiveRecord for PostgreSQL’s native data types. I am happy to announce that I have released the postgres_ext) gem.
postgres_ext supports for ActiveRecord version 3.2 and above (at this time). Parallel to my development, I plan to submit pull request to Rails master, so that postgres_ext will not be needed in Rails 4.0.
postgres_ext adds migration and
schema.rb support for the following
You can create columns with the following migration methods:
create_table :examples do |t| t.inet :ip_address # INET Column t.cidr :subnet # CIDR Column t.macaddr :mac_address # MACADDR Column t.uuid :unique_id # UUID Column t.integer :int_array, :array => true # Integer Column end
These migrations will be captured in your
schema.rb file, so you don’t
have to use the
structure.sql file if these types are your only reason. In
fact, if you are using these only supported types with
including the postgres_ext gem should allow you to correctly
db:schema:dump your database.
postgres_ext converts INET and CIDR values to IPAddr instances, and coverts arrays to array objects of the column type (integer arrays are cast as an array of integers, INET arrays to are cast to an array of IPAddrs).
INET Type Casting example
create_table :inet_examples do |t| t.inet :ip_address end class InetExample < ActiveRecord::Base end inetExample = InetExample.new inetExample.ip_address = '127.0.0.0/24' inetExample.ip_address # => #<IPAddr: IPv4:127.0.0.0/255.255.255.0> inetExample.save inet_2 = InetExample.first inet_2.ip_address # => #<IPAddr: IPv4:127.0.0.0/255.255.255.0>
Array Type Casting example
create_table :people do |t| t.integer :favorite_numbers, :array => true end class Person < ActiveRecord::Base end person = Person.new person.favorite_numbers = [1,2,3] person.favorite_numbers # => [1,2,3] person.save person_2 = Person.first person_2.favoite_numbers # => [1,2,3] person_2.favoite_numbers.first.class # => Fixnum
Another gem born out of necessity
I have also released pg_array_parserr), a C extension which parses PostgreSQL array values and returns an array of strings. This gem is used by postgres_ext to retrieve the array values before casting them to the required type.
Plans for postgres_ext
INET, CIDR and MACADDR support has already been added to Rails 4.
My next step is to submit a pull request to add UUID migration support
and Array support to Rails master. Then I plan to backport Rails 4’s
hstore support back to postgres_ext. After adding support for the other
PostgreSQL types, I plan to add support to arel for PostgreSQL type
specific where clauses (ie ANY for array comparison,
INET and CIDR comparisons.
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