sqlite: foreign key constraint checking

invenio_db/shared.py

@@ -25,6 +25,8 @@
 """Shared database object for Invenio."""
 
 from flask_sqlalchemy import SQLAlchemy as FlaskSQLAlchemy
+from sqlalchemy import event
+from sqlalchemy.engine import Engine
 
 
 class SQLAlchemy(FlaskSQLAlchemy):
@@ -43,6 +45,20 @@ def apply_driver_hacks(self, app, info, options):
                 # also stops it from emitting COMMIT before any DDL.
                 connect_args['isolation_level'] = None
 
+            event.listen(Engine, "connect", do_sqlite_connect)
+
+
+def do_sqlite_connect(dbapi_connection, connection_record):
+    """Ensure SQLite checks foreign key constraints.
+
+    For further details see "Foreign key support" sections on
+    http://docs.sqlalchemy.org/en/latest/dialects/sqlite.html
+    """
+    # Enable foreign key constraint checking
+    cursor = dbapi_connection.cursor()
+    cursor.execute("PRAGMA foreign_keys=ON")
+    cursor.close()
+
 
 db = SQLAlchemy()
 """Shared database instance using Flask-SQLAlchemy extension.

tests/test_db.py

@@ -29,12 +29,14 @@
 import importlib
 import os
 
+import pytest
 import sqlalchemy as sa
 from click.testing import CliRunner
 from flask import Flask
 from flask_cli import FlaskCLI, ScriptInfo
 from mock import patch
 from pkg_resources import EntryPoint
+from sqlalchemy.exc import IntegrityError
 from sqlalchemy_utils.functions import create_database, drop_database
 
 from invenio_db import InvenioDB, db
@@ -85,6 +87,20 @@ class Demo2(db.Model):
         create_database(db.engine.url)
         db.create_all()
         assert len(db.metadata.tables) == 2
+
+        # Test foreign key constraint checking
+        d1 = Demo()
+        db.session.add(d1)
+        d2 = Demo2(fk=d1.pk)
+        db.session.add(d2)
+        db.session.commit()
+
+        # Fails fk check
+        d3 = Demo2(fk=10)
+        db.session.add(d3)
+        pytest.raises(IntegrityError, db.session.commit)
+        db.session.rollback()
+
         db.drop_all()
         drop_database(db.engine.url)