feat: add UUIDv7Mixin (#140)

docs/module/models.md

@@ -24,7 +24,9 @@ All timestamp columns are timezone-aware (`TIMESTAMPTZ`). All defaults are serve
 
 ### [`UUIDMixin`](../reference/models.md#fastapi_toolsets.models.UUIDMixin)
 
-Adds a `id: UUID` primary key generated server-side by PostgreSQL using `gen_random_uuid()` (requires PostgreSQL 13+). The value is retrieved via `RETURNING` after insert, so it is available on the Python object immediately after `flush()`.
+Adds a `id: UUID` primary key generated server-side by PostgreSQL using `gen_random_uuid()`. The value is retrieved via `RETURNING` after insert, so it is available on the Python object immediately after `flush()`.
+
+!!! warning "Requires PostgreSQL 13+"
 
 ```python
 from fastapi_toolsets.models import UUIDMixin
@@ -36,10 +38,34 @@ class User(Base, UUIDMixin):
 
 # id is None before flush
 user = User(username="alice")
+session.add(user)
 await session.flush()
 print(user.id)  # UUID('...')
 ```
 
+### [`UUIDv7Mixin`](../reference/models.md#fastapi_toolsets.models.UUIDv7Mixin)
+
+!!! info "Added in `v2.3`"
+
+Adds a `id: UUID` primary key generated server-side by PostgreSQL using `uuidv7()`. It's a time-ordered UUID format that encodes a millisecond-precision timestamp in the most significant bits, making it naturally sortable and index-friendly.
+
+!!! warning "Requires PostgreSQL 18+"
+
+```python
+from fastapi_toolsets.models import UUIDv7Mixin
+
+class Event(Base, UUIDv7Mixin):
+    __tablename__ = "events"
+
+    name: Mapped[str]
+
+# id is None before flush
+event = Event(name="user.signup")
+session.add(event)
+await session.flush()
+print(event.id)  # UUID('019...')
+```
+
 ### [`CreatedAtMixin`](../reference/models.md#fastapi_toolsets.models.CreatedAtMixin)
 
 Adds a `created_at: datetime` column set to `clock_timestamp()` on insert. The column has no `onupdate` hook — it is intentionally immutable after the row is created.

docs/reference/models.md

@@ -7,6 +7,7 @@ You can import them directly from `fastapi_toolsets.models`:
 ```python
 from fastapi_toolsets.models import (
     UUIDMixin,
+    UUIDv7Mixin,
     CreatedAtMixin,
     UpdatedAtMixin,
     TimestampMixin,
@@ -15,6 +16,8 @@ from fastapi_toolsets.models import (
 
 ## ::: fastapi_toolsets.models.UUIDMixin
 
+## ::: fastapi_toolsets.models.UUIDv7Mixin
+
 ## ::: fastapi_toolsets.models.CreatedAtMixin
 
 ## ::: fastapi_toolsets.models.UpdatedAtMixin

src/fastapi_toolsets/models.py

@@ -8,6 +8,7 @@ from sqlalchemy.orm import Mapped, mapped_column
 
 __all__ = [
     "UUIDMixin",
+    "UUIDv7Mixin",
     "CreatedAtMixin",
     "UpdatedAtMixin",
     "TimestampMixin",
@@ -24,6 +25,16 @@ class UUIDMixin:
     )
 
 
+class UUIDv7Mixin:
+    """Mixin that adds a UUIDv7 primary key auto-generated by the database."""
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        Uuid,
+        primary_key=True,
+        server_default=text("uuidv7()"),
+    )
+
+
 class CreatedAtMixin:
     """Mixin that adds a ``created_at`` timestamp column."""
 

tests/test_models.py

@@ -11,6 +11,7 @@ from fastapi_toolsets.models import (
     CreatedAtMixin,
     TimestampMixin,
     UUIDMixin,
+    UUIDv7Mixin,
     UpdatedAtMixin,
 )
 
@@ -48,6 +49,12 @@ class TimestampModel(MixinBase, TimestampMixin):
     name: Mapped[str] = mapped_column(String(50))
 
 
+class UUIDv7Model(MixinBase, UUIDv7Mixin):
+    __tablename__ = "mixin_uuidv7_models"
+
+    name: Mapped[str] = mapped_column(String(50))
+
+
 class FullMixinModel(MixinBase, UUIDMixin, UpdatedAtMixin):
     __tablename__ = "mixin_full_models"
 
@@ -233,6 +240,50 @@ class TestTimestampMixin:
         assert "updated_at" in col_names
 
 
+class TestUUIDv7Mixin:
+    @pytest.mark.anyio
+    async def test_uuid7_generated_by_db(self, mixin_session):
+        """UUIDv7 is generated server-side and populated after flush."""
+        obj = UUIDv7Model(name="test")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+
+        assert obj.id is not None
+        assert isinstance(obj.id, uuid.UUID)
+
+    @pytest.mark.anyio
+    async def test_uuid7_is_primary_key(self):
+        """UUIDv7Mixin adds id as primary key column."""
+        pk_cols = [c.name for c in UUIDv7Model.__table__.primary_key]
+        assert pk_cols == ["id"]
+
+    @pytest.mark.anyio
+    async def test_each_row_gets_unique_uuid7(self, mixin_session):
+        """Each inserted row gets a distinct UUIDv7."""
+        a = UUIDv7Model(name="a")
+        b = UUIDv7Model(name="b")
+        mixin_session.add_all([a, b])
+        await mixin_session.flush()
+
+        assert a.id != b.id
+
+    @pytest.mark.anyio
+    async def test_uuid7_version(self, mixin_session):
+        """Generated UUIDs have version 7."""
+        obj = UUIDv7Model(name="test")
+        mixin_session.add(obj)
+        await mixin_session.flush()
+
+        assert obj.id.version == 7
+
+    @pytest.mark.anyio
+    async def test_uuid7_server_default_set(self):
+        """Column has uuidv7() as server default."""
+        col = UUIDv7Model.__table__.c["id"]
+        assert col.server_default is not None
+        assert "uuidv7" in str(col.server_default.arg)
+
+
 class TestFullMixinModel:
     @pytest.mark.anyio
     async def test_combined_mixins_work_together(self, mixin_session):