Revert microsecond precision support.

This commit partially reverts 22da5f8

django/db/backends/mysql/base.py

@@ -64,7 +64,7 @@ def adapt_datetime_warn_on_aware_datetime(value, conv):
         # This doesn't account for the database connection's timezone,
         # which isn't known. (That's why this adapter is deprecated.)
         value = value.astimezone(timezone.utc).replace(tzinfo=None)
-    return Thing2Literal(value.strftime("%Y-%m-%d %H:%M:%S.%f"), conv)
+    return Thing2Literal(value.strftime("%Y-%m-%d %H:%M:%S"), conv)
 
 # MySQLdb-1.2.1 returns TIME columns as timedelta -- they are more like
 # timedelta in terms of actual behavior as they are signed and include days --
@@ -151,7 +151,7 @@ class DatabaseWrapper(BaseDatabaseWrapper):
     # types, as strings. Column-type strings can contain format strings; they'll
     # be interpolated against the values of Field.__dict__ before being output.
     # If a column type is set to None, it won't be included in the output.
-    _data_types = {
+    data_types = {
         'AutoField': 'integer AUTO_INCREMENT',
         'BinaryField': 'longblob',
         'BooleanField': 'bool',
@@ -179,13 +179,6 @@ class DatabaseWrapper(BaseDatabaseWrapper):
         'UUIDField': 'char(32)',
     }
 
-    @cached_property
-    def data_types(self):
-        if self.features.supports_microsecond_precision:
-            return dict(self._data_types, DateTimeField='datetime(6)', TimeField='time(6)')
-        else:
-            return self._data_types
-
     operators = {
         'exact': '= %s',
         'iexact': 'LIKE %s',

django/db/backends/mysql/features.py

@@ -19,6 +19,7 @@ class DatabaseFeatures(BaseDatabaseFeatures):
     has_select_for_update = True
     has_select_for_update_nowait = False
     supports_forward_references = False
+    supports_microsecond_precision = False
     supports_regex_backreferencing = False
     supports_date_lookup_using_string = False
     can_introspect_autofield = True
@@ -46,12 +47,6 @@ def can_introspect_foreign_keys(self):
         "Confirm support for introspected foreign keys"
         return self._mysql_storage_engine != 'MyISAM'
 
-    @cached_property
-    def supports_microsecond_precision(self):
-        # See https://github.com/farcepest/MySQLdb1/issues/24 for the reason
-        # about requiring MySQLdb 1.2.5
-        return self.connection.mysql_version >= (5, 6, 4) and Database.version_info >= (1, 2, 5)
-
     @cached_property
     def has_zoneinfo_database(self):
         # MySQL accepts full time zones names (eg. Africa/Nairobi) but rejects