fix uuid column type in alembic autogeneration

.gitignore

@@ -1,4 +1,6 @@
 p38venv
+alembic
+alembic.ini
 .idea
 .pytest_cache
 .mypy_cache

docs/models.md

@@ -167,6 +167,7 @@ target_metadata = metadata
 
 
 # set your url here or import from settings
+# note that by default url is in saved sqlachemy.url variable in alembic.ini file
 URL = "sqlite:///test.db"
 
 
@@ -183,10 +184,12 @@ def run_migrations_offline():
 
     """
     context.configure(
-        url=URL
+        url=URL,
         target_metadata=target_metadata,
         literal_binds=True,
         dialect_opts={"paramstyle": "named"},
+        # if you use UUID field set also this param
+        user_module_prefix='sa.'
     )
 
     with context.begin_transaction():
@@ -205,7 +208,9 @@ def run_migrations_online():
     with connectable.connect() as connection:
         context.configure(
             connection=connection,
-            target_metadata=target_metadata
+            target_metadata=target_metadata,
+            # if you use UUID field set also this param
+            user_module_prefix='sa.'
         )
 
         with context.begin_transaction():
@@ -237,10 +242,11 @@ def include_object(object, name, type_, reflected, compare_to):
 And you pass it into context like (both in online and offline):
 ```python
 context.configure(
-        url=url,
+        url=URL,
         target_metadata=target_metadata,
         literal_binds=True,
         dialect_opts={"paramstyle": "named"},
+        user_module_prefix='sa.',
         include_object=include_object
     )
 ```

ormar/fields/sqlalchemy_uuid.py

@@ -1,15 +1,15 @@
 import uuid
 from typing import Any, Optional, Union
 
+from sqlalchemy import CHAR
 from sqlalchemy.engine.default import DefaultDialect
-from sqlalchemy.types import CHAR, TypeDecorator
+from sqlalchemy.types import TypeDecorator
 
 
 class UUID(TypeDecorator):  # pragma nocover
     """Platform-independent GUID type.
 
-    Uses Postgresql's UUID type, otherwise uses
-    CHAR(32), to store UUID.
+    Uses CHAR(36) if in a string mode, otherwise uses CHAR(32), to store UUID.
 
     """
 
@@ -19,6 +19,11 @@ class UUID(TypeDecorator):  # pragma nocover
         super().__init__(*args, **kwargs)
         self.uuid_format = uuid_format
 
+    def __repr__(self) -> str:
+        if self.uuid_format == "string":
+            return "CHAR(36)"
+        return "CHAR(32)"
+
     def _cast_to_uuid(self, value: Union[str, int, bytes]) -> uuid.UUID:
         if not isinstance(value, uuid.UUID):
             if isinstance(value, bytes):

tests/test_models.py

@@ -42,7 +42,9 @@ class UUIDSample2(ormar.Model):
         metadata = metadata
         database = database
 
-    id: uuid.UUID = ormar.UUID(primary_key=True, default=uuid.uuid4, uuid_format='string')
+    id: uuid.UUID = ormar.UUID(
+        primary_key=True, default=uuid.uuid4, uuid_format="string"
+    )
     test_text: str = ormar.Text()
 
 
@@ -321,7 +323,7 @@ async def test_model_limit_with_filter():
             await User.objects.create(name="Tom")
 
             assert (
-                    len(await User.objects.limit(2).filter(name__iexact="Tom").all()) == 2
+                len(await User.objects.limit(2).filter(name__iexact="Tom").all()) == 2
             )