PostgreSQL: `:collation` support for string and text columns

Example:

    create_table :foos do |t|
      t.string :string_en, collation: 'en_US.UTF-8'
      t.text   :text_ja,   collation: 'ja_JP.UTF-8'
    end

1 files changed, 3 insertions, 1 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
index 332ac9d88c..7e15c2ab26 100644
--- a/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb
@@ -772,7 +772,9 @@ module ActiveRecord
         def column_definitions(table_name) # :nodoc:
           exec_query(<<-end_sql, 'SCHEMA').rows
               SELECT a.attname, format_type(a.atttypid, a.atttypmod),
-                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod
+                     pg_get_expr(d.adbin, d.adrelid), a.attnotnull, a.atttypid, a.atttypmod,
+             (SELECT c.collname FROM pg_collation c, pg_type t
+               WHERE c.oid = a.attcollation AND t.oid = a.atttypid AND a.attcollation <> t.typcollation)
                 FROM pg_attribute a LEFT JOIN pg_attrdef d
                   ON a.attrelid = d.adrelid AND a.attnum = d.adnum
                WHERE a.attrelid = '#{quote_table_name(table_name)}'::regclass