Allow precision option for MySQL datetimes.

1 files changed, 12 insertions, 0 deletions

diff --git a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
index d083e413a5..ac62fb9825 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -591,6 +591,13 @@ module ActiveRecord
           when 0x1000000..0xffffffff; 'longtext'
           else raise(ActiveRecordError, "No text type has character length #{limit}")
           end
+        when 'datetime'
+          return super unless precision
+
+          case precision
+            when 0..6; "datetime(#{precision})"
+            else raise(ActiveRecordError, "No datetime type has precision of #{precision}. The allowed range of precision is from 0 to 6")
+          end
         else
           super
         end
@@ -679,6 +686,11 @@ module ActiveRecord
         m.alias_type %r(year)i,          'integer'
         m.alias_type %r(bit)i,           'binary'
 
+        m.register_type(%r(datetime)i) do |sql_type|
+          precision = extract_precision(sql_type)
+          Type::DateTime.new(precision: precision)
+        end
+
         m.register_type(%r(enum)i) do |sql_type|
           limit = sql_type[/^enum\((.+)\)/i, 1]
             .split(',').map{|enum| enum.strip.length - 2}.max