001-migration-ui-redesign (#3)

Reviewed-on: #3

backend/src/core/database.py

@@ -0,0 +1,48 @@
+# [DEF:backend.src.core.database:Module]
+#
+# @SEMANTICS: database, sqlite, sqlalchemy, session, persistence
+# @PURPOSE:   Configures the SQLite database connection and session management.
+# @LAYER:     Core
+# @RELATION:  DEPENDS_ON -> sqlalchemy
+# @RELATION:  USES -> backend.src.models.mapping
+#
+# @INVARIANT: A single engine instance is used for the entire application.
+
+# [SECTION: IMPORTS]
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker, Session
+from backend.src.models.mapping import Base
+import os
+# [/SECTION]
+
+# [DEF:DATABASE_URL:Constant]
+DATABASE_URL = os.getenv("DATABASE_URL", "sqlite:///./mappings.db")
+# [/DEF:DATABASE_URL]
+
+# [DEF:engine:Variable]
+engine = create_engine(DATABASE_URL, connect_args={"check_same_thread": False})
+# [/DEF:engine]
+
+# [DEF:SessionLocal:Class]
+SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+# [/DEF:SessionLocal]
+
+# [DEF:init_db:Function]
+# @PURPOSE: Initializes the database by creating all tables.
+def init_db():
+    Base.metadata.create_all(bind=engine)
+# [/DEF:init_db]
+
+# [DEF:get_db:Function]
+# @PURPOSE: Dependency for getting a database session.
+# @POST:    Session is closed after use.
+# @RETURN:  Generator[Session, None, None]
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+# [/DEF:get_db]
+
+# [/DEF:backend.src.core.database]