Initial commit: Tasteby - YouTube restaurant map service

Backend (FastAPI + Oracle ADB), Frontend (Next.js), daemon worker.
Features: channel/video/restaurant management, semantic search,
Google OAuth, user reviews.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend/core/db.py

@@ -0,0 +1,44 @@
+"""Oracle ADB connection pool — shared across all modules."""
+
+from __future__ import annotations
+
+import os
+from contextlib import contextmanager
+from typing import Generator, Optional
+
+import oracledb
+
+_pool: Optional[oracledb.ConnectionPool] = None
+
+
+def _get_pool() -> oracledb.ConnectionPool:
+    global _pool
+    if _pool is None:
+        kwargs: dict = dict(
+            user=os.environ["ORACLE_USER"],
+            password=os.environ["ORACLE_PASSWORD"],
+            dsn=os.environ["ORACLE_DSN"],
+            min=1,
+            max=5,
+            increment=1,
+        )
+        wallet = os.environ.get("ORACLE_WALLET")
+        if wallet:
+            kwargs["config_dir"] = wallet
+        _pool = oracledb.create_pool(**kwargs)
+    return _pool
+
+
+@contextmanager
+def conn() -> Generator[oracledb.Connection, None, None]:
+    """Acquire a pooled connection with auto-commit/rollback."""
+    pool = _get_pool()
+    c = pool.acquire()
+    try:
+        yield c
+        c.commit()
+    except Exception:
+        c.rollback()
+        raise
+    finally:
+        pool.release(c)