For sake of demonstration, add created_at and updated_at fields to CreatedUpdatedMixin used in test

Author: earshinov

tests/test_relationship_inheritance.py

@@ -1,15 +1,28 @@
+import datetime
 from typing import Optional
 
+from sqlalchemy import DateTime, func
 from sqlalchemy.orm import declared_attr, relationship
 from sqlmodel import Field, Relationship, Session, SQLModel, create_engine, select
 
 
 def test_relationship_inheritance() -> None:
+    def now():
+        return datetime.datetime.now(tz=datetime.timezone.utc)
+
     class User(SQLModel, table=True):
         id: Optional[int] = Field(default=None, primary_key=True)
         name: str
 
     class CreatedUpdatedMixin(SQLModel):
+        # Fields in reusable base models must be defined using `sa_type` and `sa_column_kwargs` instead of `sa_column`
+        # https://github.com/tiangolo/sqlmodel/discussions/743
+        #
+        # created_at: datetime.datetime = Field(default_factory=now, sa_column=DateTime(default=now))
+        created_at: datetime.datetime = Field(
+            default_factory=now, sa_type=DateTime, sa_column_kwargs={"default": now}
+        )
+
         # With Pydantic V2, it is also possible to define `created_by` like this:
         #
         #   ```python
@@ -34,6 +47,9 @@ class CreatedUpdatedMixin(SQLModel):
             )
         )
 
+        updated_at: datetime.datetime = Field(
+            default_factory=now, sa_type=DateTime, sa_column_kwargs={"default": now}
+        )
         updated_by_id: Optional[int] = Field(default=None, foreign_key="user.id")
         updated_by: Optional[User] = Relationship(
             sa_relationship=declared_attr(
@@ -43,20 +59,34 @@ class CreatedUpdatedMixin(SQLModel):
 
     class Asset(CreatedUpdatedMixin, table=True):
         id: Optional[int] = Field(default=None, primary_key=True)
+        name: str
+
+    # Demonstrate that the mixin can be applied to more than 1 model
+    class Document(CreatedUpdatedMixin, table=True):
+        id: Optional[int] = Field(default=None, primary_key=True)
+        name: str
 
     engine = create_engine("sqlite://")
 
     SQLModel.metadata.create_all(engine)
 
     john = User(name="John")
     jane = User(name="Jane")
-    asset = Asset(created_by=john, updated_by=jane)
+    asset = Asset(name="Test", created_by=john, updated_by=jane)
+    doc = Document(name="Resume", created_by=jane, updated_by=john)
 
     with Session(engine) as session:
         session.add(asset)
+        session.add(doc)
         session.commit()
 
     with Session(engine) as session:
+        assert session.scalar(select(func.count()).select_from(User)) == 2
+
         asset = session.exec(select(Asset)).one()
         assert asset.created_by.name == "John"
         assert asset.updated_by.name == "Jane"
+
+        doc = session.exec(select(Document)).one()
+        assert doc.created_by.name == "Jane"
+        assert doc.updated_by.name == "John"