Prefer SQL column type over normalized AR type

[vassilevsky]

We have columns of type point in our PostgreSQL database:

#<ActiveRecord::ConnectionAdapters::PostgreSQLColumn:0x007ffd7b829aa8
 @coder=nil,
 @default=nil,
 @limit=nil,
 @name="point",
 @null=false,
 @precision=nil,
 @primary=false,
 @scale=nil,
 @sql_type="point",
 @type=:string>

http://www.postgresql.org/docs/9.4/interactive/datatype-geometric.html

They are annotated as string in our models. This is misleading: point is actually 2 floats; not even close to a string.

I thought that SQL type should take precedence.

I understand that this change may be not enough or is completely wrong, and would welcome suggestions on the best solution.

[ctran]

A small change but with big impact. I'm not sure how other would like this.

[vassilevsky]

I think that people will like more correct annotations.

[alexch]

I'm intrigued. How is a point specified in an AR schema or migration? As a compromise, we could add the sql_type in parens if it's different from the AR type.

[ctran]

What I meant is I don't know much this will change over the existing annotations. @alexch's suggestion make sense if you don't mind making that change.

[vassilevsky]

I tested it on Rails 4.2.1 now.

rails new maps -d postgresql -T
cd maps
rails g model marker name location:point

class CreateMarkers < ActiveRecord::Migration
  def change
    create_table :markers do |t|
      t.string :name
      t.point :location

      t.timestamps null: false
    end
  end
end

rake db:create db:migrate
pgcli maps_development 

maps_development> \d markers
+------------+-----------------------------+------------------------------------------------------+
| Column     | Type                        | Modifiers                                            |
|------------+-----------------------------+------------------------------------------------------|
| id         | integer                     | not null default nextval('markers_id_seq'::regclass) |
| name       | character varying           |                                                      |
| location   | point                       |                                                      |
| created_at | timestamp without time zone | not null                                             |
| updated_at | timestamp without time zone | not null                                             |
+------------+-----------------------------+------------------------------------------------------+

# ...

ActiveRecord::Schema.define(version: 20150412093810) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"

  create_table "markers", force: :cascade do |t|
    t.string   "name"
    t.point    "location"
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
  end

end

I think that the proposed change will not cause much trouble in people's model annotations. First of all, not many people use those exotic types :) And if they do, and their strings change to points, then, after a brief wtf moment, they should feel better informed and therefore happy. Right?

[vassilevsky]

Thank you.