Ticket #6868: make_postgres_honor_scale_and_precision_with_documentation.diff

test/migration_test.rb

@@ -208 +208 @@
-      Person.connection.drop_table :testings rescue nil
-    end
-
+    def test_add_column_with_precision_and_scale
+        Person.connection.add_column Person.table_name, :cost, :decimal, :precision => 3, :scale => 2
+        # Unfortunately it's very difficult to test whether the database engine actually raises
+        # StatementInvalid because this differs a lot between database engines and versions.
+        Person.reset_column_information
+        column = Person.columns.detect { |c| c.name == 'cost' }
+        assert_equal 3, column.precision
+        assert_equal 2, column.scale
+      ensure
+        Person.connection.remove_column Person.table_name, :cost rescue nil
+    end
+
-    # We specifically do a manual INSERT here, and then test only the SELECT
-    # functionality. This allows us to more easily catch INSERT being broken,
-    # but SELECT actually working fine.

lib/active_record/connection_adapters/postgresql_adapter.rb

@@ -321 +321 @@
-        execute "ALTER TABLE #{name} RENAME TO #{new_name}"
-      end
-
+      # Add a column to a table.
+      #
+      # Options:
+      #
+      # * <tt>:limit</tt> -- Length limit for the column
+      # * <tt>:precision</tt> -- Precision for the column, this only applies on certain columns
+      # * <tt>:scale</tt> -- Scale for the column, this only applies on certain columns
+      # * <tt>:default</tt> -- The default value for the column when an INSERT doesn't specify a value
+      # * <tt>:null</tt> -- Set to false if you don't want the database to accept NULL for this column
+      #
+      # See the PosgreSQL documentation on what precision and scale exactly mean for numeric columns.
+      #
+      # Example:
+      #   add_column 'users', 'first_name', 'string', :limit => 20
+      #   add_column 'option', 'votes', 'integer'
+      #   add_column 'emissions', 'carbon_offset', 'decimal', :precision => 16, :scale => 8
+      #   add_column 'car', 'name', 'string', :null => false
-      def add_column(table_name, column_name, type, options = {})
-        default = options[:default]
-        notnull = options[:null] == false
-
-        quoted_column_name = quote_column_name(column_name)
-
-.
-quoted_column_name} #{type_to_sql(type, options[:limit
+ with limit, precision and scale
+column_name} #{type_to_sql(type, options[:limit], options[:precision], options[:scale
-
-        # Set optional default. If not null, update nulls to the new default.
-        if options_include_default?(options)