The pg_array extension adds support for
Sequel to handle PostgreSQL's array types.
This extension integrates with Sequel's native postgres adapter and the jdbc/postgresql adapter, so that when array fields are retrieved, they are parsed and returned as instances of
Sequel::Postgres::PGArray. PGArray is a DelegateClass of
Array, so it mostly acts like an array, but not completely (is_a?(Array) is false). If you want the actual array, you can call PGArray#to_a. This is done so that
Sequel does not treat a PGArray like an
Array by default, which would cause issues.
In addition to the parsers, this extension comes with literalizers for PGArray using the standard
Sequel literalization callbacks, so they work with on all adapters.
To turn an existing
Array into a PGArray:
You can also provide a type, though in many cases it isn't necessary:
Sequel.pg_array(array, :varchar) # or :integer, :"double precision", etc. array.pg_array(:varchar) # or :integer, :"double precision", etc.
So if you want to insert an array into an integer database column:
DB[:table].insert(column: Sequel.pg_array([1, 2, 3]))
To use this extension, first load it into your Sequel::Database instance:
See the schema modification guide for details on using postgres array columns in CREATE/ALTER TABLE statements.
This extension by default includes handlers for array types for all scalar types that the native postgres adapter handles. It also makes it easy to add support for other array types. In general, you just need to make sure that the scalar type is handled and has the appropriate converter installed. For user defined types, you can do this via:
Then you can call
Sequel::Postgres::PGArray::DatabaseMethods#register_array_type to automatically set up a handler for the array type. So if you want to support the foo type (assuming the foo type is already supported):
While this extension can parse PostgreSQL arrays with explicit bounds, it currently ignores explicit bounds, so such values do not round trip.
If you want an easy way to call PostgreSQL array functions and operators, look into the pg_array_ops extension.
This extension requires the delegate library, and the strscan library sequel_pg has not been loaded.