Normalized the implementation of get_db_converters.

Put the types in the same order and checked for None consistently.

django/db/backends/base/operations.py

@@ -505,10 +505,11 @@ class BaseDatabaseOperations(object):
         return [first, second]
 
     def get_db_converters(self, expression):
-        """Get a list of functions needed to convert field data.
+        """
+        Get a list of functions needed to convert field data.
 
         Some field types on some backends do not provide data in the correct
-        format, this is the hook for coverter functions.
+        format, this is the hook for converter functions.
         """
         return []
 

django/db/backends/mysql/operations.py

@@ -182,16 +182,21 @@ class DatabaseOperations(BaseDatabaseOperations):
     def get_db_converters(self, expression):
         converters = super(DatabaseOperations, self).get_db_converters(expression)
         internal_type = expression.output_field.get_internal_type()
-        if internal_type in ['BooleanField', 'NullBooleanField']:
+        if internal_type == 'TextField':
+            converters.append(self.convert_textfield_value)
+        elif internal_type in ['BooleanField', 'NullBooleanField']:
             converters.append(self.convert_booleanfield_value)
-        if internal_type == 'DateTimeField':
+        elif internal_type == 'DateTimeField':
             converters.append(self.convert_datetimefield_value)
-        if internal_type == 'UUIDField':
+        elif internal_type == 'UUIDField':
             converters.append(self.convert_uuidfield_value)
-        if internal_type == 'TextField':
-            converters.append(self.convert_textfield_value)
         return converters
 
+    def convert_textfield_value(self, value, expression, connection, context):
+        if value is not None:
+            value = force_text(value)
+        return value
+
     def convert_booleanfield_value(self, value, expression, connection, context):
         if value in (0, 1):
             value = bool(value)
@@ -207,8 +212,3 @@ class DatabaseOperations(BaseDatabaseOperations):
         if value is not None:
             value = uuid.UUID(value)
         return value
-
-    def convert_textfield_value(self, value, expression, connection, context):
-        if value is not None:
-            value = force_text(value)
-        return value

django/db/backends/oracle/operations.py

@@ -174,18 +174,6 @@ WHEN (new.%(col_name)s IS NULL)
         converters.append(self.convert_empty_values)
         return converters
 
-    def convert_empty_values(self, value, expression, connection, context):
-        # Oracle stores empty strings as null. We need to undo this in
-        # order to adhere to the Django convention of using the empty
-        # string instead of null, but only if the field accepts the
-        # empty string.
-        field = expression.output_field
-        if value is None and field.empty_strings_allowed:
-            value = ''
-            if field.get_internal_type() == 'BinaryField':
-                value = b''
-        return value
-
     def convert_textfield_value(self, value, expression, connection, context):
         if isinstance(value, Database.LOB):
             value = force_text(value.read())
@@ -197,7 +185,7 @@ WHEN (new.%(col_name)s IS NULL)
         return value
 
     def convert_booleanfield_value(self, value, expression, connection, context):
-        if value in (1, 0):
+        if value in (0, 1):
             value = bool(value)
         return value
 
@@ -213,7 +201,8 @@ WHEN (new.%(col_name)s IS NULL)
 
     def convert_datefield_value(self, value, expression, connection, context):
         if isinstance(value, Database.Timestamp):
-            return value.date()
+            value = value.date()
+        return value
 
     def convert_timefield_value(self, value, expression, connection, context):
         if isinstance(value, Database.Timestamp):
@@ -225,6 +214,18 @@ WHEN (new.%(col_name)s IS NULL)
             value = uuid.UUID(value)
         return value
 
+    def convert_empty_values(self, value, expression, connection, context):
+        # Oracle stores empty strings as null. We need to undo this in
+        # order to adhere to the Django convention of using the empty
+        # string instead of null, but only if the field accepts the
+        # empty string.
+        field = expression.output_field
+        if value is None and field.empty_strings_allowed:
+            value = ''
+            if field.get_internal_type() == 'BinaryField':
+                value = b''
+        return value
+
     def deferrable_sql(self):
         return " DEFERRABLE INITIALLY DEFERRED"
 

django/db/backends/sqlite3/operations.py

@@ -151,15 +151,6 @@ class DatabaseOperations(BaseDatabaseOperations):
             converters.append(self.convert_uuidfield_value)
         return converters
 
-    def convert_decimalfield_value(self, value, expression, connection, context):
-        return backend_utils.typecast_decimal(expression.output_field.format_number(value))
-
-    def convert_datefield_value(self, value, expression, connection, context):
-        if value is not None:
-            if not isinstance(value, datetime.date):
-                value = parse_date(value)
-        return value
-
     def convert_datetimefield_value(self, value, expression, connection, context):
         if value is not None:
             if not isinstance(value, datetime.datetime):
@@ -168,12 +159,24 @@ class DatabaseOperations(BaseDatabaseOperations):
                 value = value.replace(tzinfo=timezone.utc)
         return value
 
+    def convert_datefield_value(self, value, expression, connection, context):
+        if value is not None:
+            if not isinstance(value, datetime.date):
+                value = parse_date(value)
+        return value
+
     def convert_timefield_value(self, value, expression, connection, context):
         if value is not None:
             if not isinstance(value, datetime.time):
                 value = parse_time(value)
         return value
 
+    def convert_decimalfield_value(self, value, expression, connection, context):
+        if value is not None:
+            value = expression.output_field.format_number(value)
+            value = backend_utils.typecast_decimal(value)
+        return value
+
     def convert_uuidfield_value(self, value, expression, connection, context):
         if value is not None:
             value = uuid.UUID(value)