switch pool for sqlite with new factory, add tests if fks are reflected in db

docs/releases.md

@@ -1,3 +1,27 @@
+# 0.9.0
+
+## Important
+* **Braking Fix:** Version 0.8.0 introduced a bug that prevents generation of foreign_keys constraint in the database,
+both in alembic and during creation through sqlalchemy.engine, this is fixed now.
+* **THEREFORE IF YOU USE VERSION >=0.8.0 YOU ARE STRONGLY ADVISED TO UPDATE** cause despite
+that most of the `ormar` functions are working your database **CREATED with ormar (or ormar + alembic)** 
+  does not have relations and suffer from perspective of performance and data integrity.
+* If you were using `ormar` to connect to existing database your performance and integrity 
+  should be fine nevertheless you should update to reflect all future schema updates in your models.
+
+
+## Breaking
+* **Breaking:** All foreign_keys and unique constraints now have a name so `alembic` 
+  can identify them in db and not depend on db
+* **Breaking:** During model construction if `Meta` class of the `Model` does not 
+  include `metadata` or `database` now `ModelDefinitionError` will be raised instead of generic `AttributeError`.
+* **Breaking:** `encode/databases` used for running the queries does not have a connection pool
+for sqlite backend, meaning that each querry is run with a new connection and there is no way to 
+  enable enforcing ForeignKeys constraints as those are by default turned off on every connection.
+  This is changed in `ormar` since >=0.9.0 and by default each sqlite3 query has `"PRAGMA foreign_keys=1;"`
+  run so now each sqlite3 connection by default enforces ForeignKey constraints including cascades.
+
+
 # 0.8.1
 
 ## Features

ormar/fields/model_fields.py

@@ -214,7 +214,7 @@ class Integer(ModelFieldFactory, int):
         :return: initialized column with proper options
         :rtype: sqlalchemy Column
         """
-        return sqlalchemy.Integer
+        return sqlalchemy.Integer()
 
 
 class Text(ModelFieldFactory, str):

ormar/models/helpers/models.py

@@ -1,10 +1,11 @@
 import itertools
+import sqlite3
 from typing import Any, Dict, List, Optional, TYPE_CHECKING, Tuple, Type
 
+from pydantic.typing import ForwardRef
 import ormar  # noqa: I100
 from ormar.fields.foreign_key import ForeignKeyField
 from ormar.models.helpers.pydantic import populate_pydantic_default_values
-from pydantic.typing import ForwardRef
 
 if TYPE_CHECKING:  # pragma no cover
     from ormar import Model
@@ -41,7 +42,7 @@ def populate_default_options_values(
 
     :param new_model: newly constructed Model
     :type new_model: Model class
-    :param model_fields:
+    :param model_fields: dict of model fields
     :type model_fields: Union[Dict[str, type], Dict]
     """
     if not hasattr(new_model.Meta, "constraints"):
@@ -59,6 +60,54 @@ def populate_default_options_values(
         new_model.Meta.requires_ref_update = False
 
 
+class Connection(sqlite3.Connection):
+    def __init__(self, *args: Any, **kwargs: Any) -> None:
+        super().__init__(*args, **kwargs)
+        self.execute("PRAGMA foreign_keys=1;")
+
+
+def substitue_backend_pool_for_sqlite(new_model: Type["Model"]) -> None:
+    """
+    Recreates Connection pool for sqlite3 with new factory that
+    executes "PRAGMA foreign_keys=1; on initialization to enable foreign keys.
+
+    :param new_model: newly declared ormar Model
+    :type new_model: Model class
+    """
+    backend = new_model.Meta.database._backend
+    if (
+        backend._dialect.name == "sqlite" and "factory" not in backend._options
+    ):  # pragma: no cover
+        backend._options["factory"] = Connection
+        old_pool = backend._pool
+        backend._pool = old_pool.__class__(backend._database_url, **backend._options)
+
+
+def check_required_meta_parameters(new_model: Type["Model"]) -> None:
+    """
+    Verifies if ormar.Model has database and metadata set.
+
+    Recreates Connection pool for sqlite3
+
+    :param new_model: newly declared ormar Model
+    :type new_model: Model class
+    """
+    if not hasattr(new_model.Meta, "database"):
+        if not getattr(new_model.Meta, "abstract", False):
+            raise ormar.ModelDefinitionError(
+                f"{new_model.__name__} does not have database defined."
+            )
+
+    else:
+        substitue_backend_pool_for_sqlite(new_model=new_model)
+
+    if not hasattr(new_model.Meta, "metadata"):
+        if not getattr(new_model.Meta, "abstract", False):
+            raise ormar.ModelDefinitionError(
+                f"{new_model.__name__} does not have metadata defined."
+            )
+
+
 def extract_annotations_and_default_vals(attrs: Dict) -> Tuple[Dict, Dict]:
     """
     Extracts annotations from class namespace dict and triggers

ormar/models/metaclass.py

@@ -33,6 +33,7 @@ from ormar.models.helpers import (
     populate_meta_tablename_columns_and_pk,
     register_relation_in_alias_manager,
 )
+from ormar.models.helpers.models import check_required_meta_parameters
 from ormar.models.helpers.sqlalchemy import sqlalchemy_columns_from_model_fields
 from ormar.models.quick_access_views import quick_access_set
 from ormar.queryset import QuerySet
@@ -582,6 +583,7 @@ class ModelMetaclass(pydantic.main.ModelMetaclass):
 
         if hasattr(new_model, "Meta"):
             populate_default_options_values(new_model, model_fields)
+            check_required_meta_parameters(new_model)
             add_property_fields(new_model, attrs)
             register_signals(new_model=new_model)
             populate_choices_validators(new_model)

ormar/models/model.py

@@ -62,6 +62,10 @@ class Model(NewBaseModel):
         where rows are populated in a different way as they do not have
         nested models in result.
 
+        :param current_relation_str: name of the relation field
+        :type current_relation_str: str
+        :param source_model: model on which relation was defined
+        :type source_model: Type[Model]
         :param row: raw result row from the database
         :type row: sqlalchemy.engine.result.ResultProxy
         :param select_related: list of names of related models fetched from database

ormar/queryset/queryset.py

@@ -590,7 +590,6 @@ class QuerySet:
         expr = FilterQuery(filter_clauses=self.filter_clauses).apply(
             self.table.delete()
         )
-        print("\n", expr.compile(compile_kwargs={"literal_binds": True}))
         return await self.database.execute(expr)
 
     def paginate(self, page: int, page_size: int = 20) -> "QuerySet":

tests/test_cascades.py

@@ -1,27 +1,14 @@
-import time
 from typing import Optional
 
 import databases
 import pytest
 import sqlalchemy
-from sqlalchemy import (
-    Column,
-    ForeignKey,
-    ForeignKeyConstraint,
-    Integer,
-    String,
-    Table,
-    create_engine,
-    inspect,
-)
-from sqlalchemy.dialects import postgresql
 
 import ormar
 from tests.settings import DATABASE_URL
 
 database = databases.Database(DATABASE_URL)
 metadata = sqlalchemy.MetaData()
-engine = sqlalchemy.create_engine(DATABASE_URL, echo=True)
 
 
 class Artist(ormar.Model):
@@ -45,43 +32,34 @@ class Album(ormar.Model):
     artist: Optional[Artist] = ormar.ForeignKey(Artist, ondelete="CASCADE")
 
 
-#
-# class Track(ormar.Model):
-#     class Meta:
-#         tablename = "tracks"
-#         metadata = metadata
-#         database = database
-#
-#     id: int = ormar.Integer(primary_key=True)
-#     album: Optional[Album] = ormar.ForeignKey(Album, ondelete='CASCADE')
-#     title: str = ormar.String(max_length=100)
+class Track(ormar.Model):
+    class Meta:
+        tablename = "tracks"
+        metadata = metadata
+        database = database
+
+    id: int = ormar.Integer(primary_key=True)
+    album: Optional[Album] = ormar.ForeignKey(Album, ondelete="CASCADE")
+    title: str = ormar.String(max_length=100)
 
 
 @pytest.fixture(autouse=True, scope="module")
 def create_test_database():
-    # if "sqlite" in DATABASE_URL:
-    #     with engine.connect() as connection:
-    #         connection.execute("PRAGMA foreign_keys = ON;")
+    engine = sqlalchemy.create_engine(DATABASE_URL)
     metadata.drop_all(engine)
     metadata.create_all(engine)
-    # tables = list(metadata.tables.values())
-    # tab = Album.Meta.table
-    # breakpoint()
     yield
-    # metadata.drop_all(engine)
+    metadata.drop_all(engine)
 
 
 @pytest.mark.asyncio
 async def test_simple_cascade():
     async with database:
-        # async with database.transaction(force_rollback=True):
         artist = await Artist(name="Dr Alban").save()
         await Album(name="Jamaica", artist=artist).save()
         await Artist.objects.delete(id=artist.id)
-
         artists = await Artist.objects.all()
         assert len(artists) == 0
 
-    async with database:
         albums = await Album.objects.all()
         assert len(albums) == 0

tests/test_database_fk_creation.py

@@ -0,0 +1,55 @@
+from typing import Optional
+
+import databases
+import pytest
+import sqlalchemy
+
+import ormar
+from tests.settings import DATABASE_URL
+
+database = databases.Database(DATABASE_URL)
+metadata = sqlalchemy.MetaData()
+engine = sqlalchemy.create_engine(DATABASE_URL)
+
+
+class Artist(ormar.Model):
+    class Meta:
+        tablename = "artists"
+        metadata = metadata
+        database = database
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+
+
+class Album(ormar.Model):
+    class Meta:
+        tablename = "albums"
+        metadata = metadata
+        database = database
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+    artist: Optional[Artist] = ormar.ForeignKey(Artist, ondelete="CASCADE")
+
+
+@pytest.fixture(autouse=True, scope="module")
+def create_test_database():
+    metadata.drop_all(engine)
+    metadata.create_all(engine)
+    yield
+    metadata.drop_all(engine)
+
+
+def test_simple_cascade():
+    inspector = sqlalchemy.inspect(engine)
+    columns = inspector.get_columns("albums")
+    assert len(columns) == 3
+    col_names = [col.get("name") for col in columns]
+    assert sorted(["id", "name", "artist"]) == sorted(col_names)
+    fks = inspector.get_foreign_keys("albums")
+    assert len(fks) == 1
+    assert fks[0]["name"] == "fk_albums_artists_id_artist"
+    assert fks[0]["constrained_columns"][0] == "artist"
+    assert fks[0]["referred_columns"][0] == "id"
+    assert fks[0]["options"].get("ondelete") == "CASCADE"

tests/test_model_definition.py

@@ -3,6 +3,7 @@ import asyncio
 import datetime
 import decimal
 
+import databases
 import pydantic
 import pytest
 import sqlalchemy
@@ -14,12 +15,16 @@ from ormar.models import Model
 from tests.settings import DATABASE_URL
 
 metadata = sqlalchemy.MetaData()
+from tests.settings import DATABASE_URL
+
+database = databases.Database(DATABASE_URL, force_rollback=True)
 
 
 class ExampleModel(Model):
     class Meta:
         tablename = "example"
         metadata = metadata
+        database = database
 
     test: int = ormar.Integer(primary_key=True)
     test_string: str = ormar.String(max_length=250)
@@ -52,6 +57,7 @@ class ExampleModel2(Model):
     class Meta:
         tablename = "examples"
         metadata = metadata
+        database = database
 
     test: int = ormar.Integer(primary_key=True)
     test_string: str = ormar.String(max_length=250)