1 files changed, 28 insertions, 31 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 5c8c4b883a..8db4bcd7e3 100644
--- a/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
+++ b/activerecord/lib/active_record/connection_adapters/abstract_mysql_adapter.rb
@@ -63,7 +63,7 @@ module ActiveRecord
 
       def column_spec_for_primary_key(column)
         spec = {}
-        if column.extra == 'auto_increment'
+        if column.auto_increment?
           return unless column.limit == 8
           spec[:id] = ':bigint'
         else
@@ -73,6 +73,12 @@ module ActiveRecord
         spec
       end
 
+      def prepare_column_options(column)
+        spec = super
+        spec.delete(:precision) if /time/ === column.sql_type && column.precision == 0
+        spec
+      end
+
       class Column < ConnectionAdapters::Column # :nodoc:
         delegate :strict, :collation, :extra, to: :sql_type_metadata, allow_nil: true
 
@@ -103,6 +109,10 @@ module ActiveRecord
           collation && !collation.match(/_ci$/)
         end
 
+        def auto_increment?
+          extra == 'auto_increment'
+        end
+
         private
 
         # MySQL misreports NOT NULL column default when none is given.
@@ -241,6 +251,10 @@ module ActiveRecord
         version[0] >= 5
       end
 
+      def supports_datetime_with_precision?
+        (version[0] == 5 && version[1] >= 6) || version[0] >= 6
+      end
+
       def native_database_types
         NATIVE_DATABASE_TYPES
       end
@@ -613,13 +627,6 @@ 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
@@ -708,11 +715,6 @@ 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)
-          MysqlDateTime.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
@@ -730,6 +732,14 @@ module ActiveRecord
         end
       end
 
+      def extract_precision(sql_type)
+        if /time/ === sql_type
+          super || 0
+        else
+          super
+        end
+      end
+
       def fetch_type_metadata(sql_type, collation = "", extra = "")
         MysqlTypeMetadata.new(super(sql_type), collation: collation, extra: extra, strict: strict_mode?)
       end
@@ -808,7 +818,7 @@ module ActiveRecord
         options = {
           default: column.default,
           null: column.null,
-          auto_increment: column.extra == "auto_increment"
+          auto_increment: column.auto_increment?
         }
 
         current_type = select_one("SHOW COLUMNS FROM #{quote_table_name(table_name)} LIKE '#{column_name}'", 'SCHEMA')["Type"]
@@ -912,24 +922,8 @@ module ActiveRecord
         TableDefinition.new(native_database_types, name, temporary, options, as)
       end
 
-      class MysqlDateTime < Type::DateTime # :nodoc:
-        def type_cast_for_database(value)
-          if value.acts_like?(:time) && value.respond_to?(:usec)
-            result = super.to_s(:db)
-            case precision
-            when 1..6
-              "#{result}.#{sprintf("%0#{precision}d", value.usec / 10 ** (6 - precision))}"
-            else
-              result
-            end
-          else
-            super
-          end
-        end
-      end
-
       class MysqlString < Type::String # :nodoc:
-        def type_cast_for_database(value)
+        def serialize(value)
           case value
           when true then "1"
           when false then "0"
@@ -947,6 +941,9 @@ module ActiveRecord
           end
         end
       end
+
+      ActiveRecord::Type.register(:string, MysqlString, adapter: :mysql)
+      ActiveRecord::Type.register(:string, MysqlString, adapter: :mysql2)
     end
   end
 end