change_column_default

# File activerecord/lib/active_record/connection_adapters/postgresql/schema_statements.rb, line 411
        def change_column_default(table_name, column_name, default)
          clear_cache!
          column = column_for(table_name, column_name)

          execute "ALTER TABLE #{quote_table_name(table_name)} ALTER COLUMN #{quote_column_name(column_name)} SET DEFAULT #{quote_default_value(default, column)}" if column
        end