Backend-agnostic GUID Type
^^^^^^^^^^^^^^^^^^^^^^^^^^
-Receives and returns Python uuid() objects. Uses the PG UUID type
-when using PostgreSQL, CHAR(32) on other backends, storing them
-in stringified hex format. Can be modified to store
-binary in CHAR(16) if desired::
-
+.. note:: Since version 2.0 the built-in :class:`_types.Uuid` type that
+ behaves similarly should be preferred. This example is presented
+ just as an example of a type decorator that recieves and returns
+ python objects.
+
+Receives and returns Python uuid() objects.
+Uses the PG UUID type when using PostgreSQL, UNIQUEIDENTIFIER when using MSSQL,
+CHAR(32) on other backends, storing them in stringified format.
+The ``GUIDHyphens`` version stores the value with hyphens instead of just the hex
+string, using a CHAR(36) type::
+
+ from operator import attrgetter
from sqlalchemy.types import TypeDecorator, CHAR
+ from sqlalchemy.dialects.mssql import UNIQUEIDENTIFIER
from sqlalchemy.dialects.postgresql import UUID
import uuid
class GUID(TypeDecorator):
"""Platform-independent GUID type.
- Uses PostgreSQL's UUID type, otherwise uses
- CHAR(32), storing as stringified hex values.
+ Uses PostgreSQL's UUID type or MSSQL's UNIQUEIDENTIFIER,
+ otherwise uses CHAR(32), storing as stringified hex values.
"""
impl = CHAR
cache_ok = True
+ _default_type = CHAR(32)
+ _uuid_as_str = attrgetter("hex")
+
def load_dialect_impl(self, dialect):
if dialect.name == "postgresql":
return dialect.type_descriptor(UUID())
+ elif dialect.name == "mssql":
+ return dialect.type_descriptor(UNIQUEIDENTIFIER())
else:
- return dialect.type_descriptor(CHAR(32))
+ return dialect.type_descriptor(self._default_type)
def process_bind_param(self, value, dialect):
if value is None:
return value
- elif dialect.name == "postgresql":
+ elif dialect.name in ("postgresql", "mssql"):
return str(value)
else:
if not isinstance(value, uuid.UUID):
- return "%.32x" % uuid.UUID(value).int
- else:
- # hexstring
- return "%.32x" % value.int
+ value = uuid.UUID(value)
+ return self._uuid_as_str(value)
def process_result_value(self, value, dialect):
if value is None:
value = uuid.UUID(value)
return value
+
+ class GUIDHyphens(GUID):
+ """Platform-independent GUID type.
+
+ Uses PostgreSQL's UUID type or MSSQL's UNIQUEIDENTIFIER,
+ otherwise uses CHAR(36), storing as stringified uuid values.
+
+ """
+
+ _default_type = CHAR(36)
+ _uuid_as_str = str
+
Linking Python ``uuid.UUID`` to the Custom Type for ORM mappings
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
projects / thirdparty / sqlalchemy / sqlalchemy.git / commitdiff
