无法访问Postgis的方法

Question

I try to build my rails env with postgis. The following is the extension of my db:

                                        List of installed extensions
       Name       | Version |   Schema   |                             Description                             
------------------+---------+------------+---------------------------------------------------------------------

 plpgsql          | 1.0     | pg_catalog | PL/pgSQL procedural language

 postgis          | 2.1.3   | public     | PostGIS geometry, geography, and raster spatial types and functions

 postgis_topology | 2.1.3   | topology   | PostGIS topology spatial types and functions
(3 rows)

And I also can see the " t.spatial "location", limit: {:srid=>0, :type=>"geometry"}" in my schema.rb after add column and migration the database.

While in the console and rb file, I can't access the postgis method like:

> e.location = ST_GeomFromText('POINT(121.04238 24.777656)', 4326)
NoMethodError: undefined method `ST_GeomFromText' for main:Object
    from (irb):2
    from /usr/local/rvm/gems/ruby-2.1.2/gems/railties-4.1.4/lib/rails/commands/console.rb:90:in `start'
    from /usr/local/rvm/gems/ruby-2.1.2/gems/railties-4.1.4/lib/rails/commands/console.rb:9:in `start'
    from /usr/local/rvm/gems/ruby-2.1.2/gems/railties-4.1.4/lib/rails/commands/commands_tasks.rb:69:in `console'
    from /usr/local/rvm/gems/ruby-2.1.2/gems/railties-4.1.4/lib/rails/commands/commands_tasks.rb:40:in `run_command!'
    from /usr/local/rvm/gems/ruby-2.1.2/gems/railties-4.1.4/lib/rails/commands.rb:17:in `<top (required)>' 

Or in ruby file:

@data.location = ST_GeomFromText('POINT(' + params[:longitude] +' ' + params[:latitude] + ')', 4326)

get the server error:

NoMethodError (undefined method `ST_GeomFromText' for #<DataController:0x000000053ee388>):

I try some idea from internet, but can't figure it out.

Answer 1

PostGIS' methods are supposed to be used in SQLs, rather than Ruby code. See examples in the official document