add delete cascade to entity to delete search_index (postgres only)

Signed-off-by: phernandez <paul@basicmachines.co>

Author: phernandez

src/basic_memory/alembic/versions/a2b3c4d5e6f7_add_search_index_entity_cascade.py

@@ -0,0 +1,56 @@
+"""Add cascade delete FK from search_index to entity
+
+Revision ID: a2b3c4d5e6f7
+Revises: f8a9b2c3d4e5
+Create Date: 2025-12-02 07:00:00.000000
+
+"""
+
+from typing import Sequence, Union
+
+from alembic import op
+
+
+# revision identifiers, used by Alembic.
+revision: str = "a2b3c4d5e6f7"
+down_revision: Union[str, None] = "f8a9b2c3d4e5"
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+    """Add FK with CASCADE delete from search_index.entity_id to entity.id.
+
+    This migration is Postgres-only because:
+    - SQLite uses FTS5 virtual tables which don't support foreign keys
+    - The FK enables automatic cleanup of search_index entries when entities are deleted
+    """
+    connection = op.get_bind()
+    dialect = connection.dialect.name
+
+    if dialect == "postgresql":
+        # First, clean up any orphaned search_index entries where entity no longer exists
+        op.execute("""
+            DELETE FROM search_index
+            WHERE entity_id IS NOT NULL
+            AND entity_id NOT IN (SELECT id FROM entity)
+        """)
+
+        # Add FK with CASCADE - nullable FK allows search_index entries without entity_id
+        op.create_foreign_key(
+            "fk_search_index_entity_id",
+            "search_index",
+            "entity",
+            ["entity_id"],
+            ["id"],
+            ondelete="CASCADE",
+        )
+
+
+def downgrade() -> None:
+    """Remove the FK constraint."""
+    connection = op.get_bind()
+    dialect = connection.dialect.name
+
+    if dialect == "postgresql":
+        op.drop_constraint("fk_search_index_entity_id", "search_index", type_="foreignkey")

src/basic_memory/models/search.py

@@ -1,6 +1,6 @@
 """Search models and tables."""
 
-from sqlalchemy import DDL, Column, Integer, String, DateTime, Text
+from sqlalchemy import DDL, Column, Integer, String, DateTime, Text, ForeignKey
 from sqlalchemy.dialects.postgresql import JSONB
 from sqlalchemy.types import JSON
 
@@ -36,7 +36,9 @@ class SearchIndex(Base):
     relation_type = Column(String(100), nullable=True)
 
     # Observation fields
-    entity_id = Column(Integer, nullable=True)
+    # Note: FK with CASCADE only applies to Postgres. SQLite uses FTS5 virtual tables
+    # which don't support foreign keys, so cascade delete is handled explicitly there.
+    entity_id = Column(Integer, ForeignKey("entity.id", ondelete="CASCADE"), nullable=True)
     category = Column(String(100), nullable=True)
 
     # Common fields

test-int/test_db_wal_mode.py

@@ -5,7 +5,6 @@
 """
 
 import pytest
-from unittest.mock import patch
 from sqlalchemy import text
 
 
@@ -142,8 +141,6 @@ async def test_null_pool_on_windows(tmp_path, monkeypatch):
         assert isinstance(engine.pool, NullPool)
 
 
-
-
 @pytest.mark.asyncio
 @pytest.mark.windows
 @pytest.mark.skipif(