allow uuid_format add more tests and update docs

docs/fields.md

@@ -251,11 +251,21 @@ You can use either `length` and `precision` parameters or `max_digits` and `deci
 
 ### UUID
 
-`UUID()` has no required parameters.  
+`UUID(uuid_format: str = 'hex')` has no required parameters.  
 
-* Sqlalchemy column: `ormar.UUID` based on `sqlalchemy.CHAR` field  
+* Sqlalchemy column: `ormar.UUID` based on `sqlalchemy.CHAR(36)` or `sqlalchemy.CHAR(32)` field (for string or hex format respectively)  
 * Type (used for pydantic): `uuid.UUID` 
 
+`uuid_format` parameters allow 'hex'(default) or 'string' values.
+
+Depending on the format either 32 or 36 char is used in the database.
+
+Sample:
+*  'hex' format value = "c616ab438cce49dbbf4380d109251dce" (CHAR(32))
+*  'string' value = "c616ab43-8cce-49db-bf43-80d109251dce" (CHAR(36))  
+
+When loaded it's always python UUID so you can compare it and compare two formats values between each other.
+
 [relations]: ./relations.md
 [queries]: ./queries.md
 [pydantic]: https://pydantic-docs.helpmanual.io/usage/types/#constrained-types

docs/releases.md

@@ -1,7 +1,11 @@
-# 0.6.0
+# 0.5.4
 
-*  **Breaking** Changed `UUID` field that was trimmed to 32 chars (without dashes) instead of 36 (with dashes) 
-   to more in line with other libraries.
+*  Allow to pass `uuid_format` (allowed 'hex'(default) or 'string') to `UUID` field to change the format in which it's saved.
+   By default field is saved in hex format (trimmed to 32 chars (without dashes)), but you can pass 
+   format='string' to use 36 (with dashes) instead to adjust to existing db or other libraries.
+   Sample:
+   hex value = c616ab438cce49dbbf4380d109251dce
+   string value = c616ab43-8cce-49db-bf43-80d109251dce
 
 # 0.5.3
 

ormar/fields/model_fields.py

@@ -318,6 +318,21 @@ class Decimal(ModelFieldFactory, decimal.Decimal):
 class UUID(ModelFieldFactory, uuid.UUID):
     _type = uuid.UUID
 
+    def __new__(  # type: ignore # noqa CFQ002
+        cls, *, uuid_format: str = "hex", **kwargs: Any
+    ) -> Type[BaseField]:
+        kwargs = {
+            **kwargs,
+            **{
+                k: v
+                for k, v in locals().items()
+                if k not in ["cls", "__class__", "kwargs"]
+            },
+        }
+
+        return super().__new__(cls, **kwargs)
+
     @classmethod
     def get_column_type(cls, **kwargs: Any) -> Any:
-        return sqlalchemy_uuid.UUID()
+        uuid_format = kwargs.get("uuid_format", "hex")
+        return sqlalchemy_uuid.UUID(uuid_format=uuid_format)

ormar/fields/sqlalchemy_uuid.py

@@ -15,6 +15,10 @@ class UUID(TypeDecorator):  # pragma nocover
 
     impl = CHAR
 
+    def __init__(self, *args: Any, uuid_format: str = "hex", **kwargs: Any) -> None:
+        super().__init__(*args, **kwargs)
+        self.uuid_format = uuid_format
+
     def _cast_to_uuid(self, value: Union[str, int, bytes]) -> uuid.UUID:
         if not isinstance(value, uuid.UUID):
             if isinstance(value, bytes):
@@ -28,7 +32,11 @@ class UUID(TypeDecorator):  # pragma nocover
         return ret_value
 
     def load_dialect_impl(self, dialect: DefaultDialect) -> Any:
-        return dialect.type_descriptor(CHAR(36))
+        return (
+            dialect.type_descriptor(CHAR(36))
+            if self.uuid_format == "string"
+            else dialect.type_descriptor(CHAR(32))
+        )
 
     def process_bind_param(
         self, value: Union[str, int, bytes, uuid.UUID, None], dialect: DefaultDialect
@@ -37,7 +45,7 @@ class UUID(TypeDecorator):  # pragma nocover
             return value
         if not isinstance(value, uuid.UUID):
             value = self._cast_to_uuid(value)
-        return str(value)
+        return str(value) if self.uuid_format == "string" else "%.32x" % value.int
 
     def process_result_value(
         self, value: Optional[str], dialect: DefaultDialect

tests/test_models.py

@@ -36,6 +36,16 @@ class UUIDSample(ormar.Model):
     test_text: str = ormar.Text()
 
 
+class UUIDSample2(ormar.Model):
+    class Meta:
+        tablename = "uuids2"
+        metadata = metadata
+        database = database
+
+    id: uuid.UUID = ormar.UUID(primary_key=True, default=uuid.uuid4, uuid_format='string')
+    test_text: str = ormar.Text()
+
+
 class User(ormar.Model):
     class Meta:
         tablename = "users"
@@ -150,6 +160,14 @@ async def test_uuid_column():
             assert item2.id == item3.id
             assert isinstance(item3.id, uuid.UUID)
 
+            u3 = await UUIDSample2(**u1.dict()).save()
+
+            u1_2 = await UUIDSample.objects.get(pk=u3.id)
+            assert u1_2 == u1
+
+            u4 = await UUIDSample2.objects.get(pk=u3.id)
+            assert u3 == u4
+
 
 @pytest.mark.asyncio
 async def test_model_crud():