feat: complete huihui square avatar workflows

digital-avatar-app/backend/database.py

@@ -0,0 +1,49 @@
+import os
+
+from sqlalchemy import create_engine
+from sqlalchemy.orm import sessionmaker, declarative_base, Session
+
+BASE_DIR = os.path.dirname(os.path.abspath(__file__))
+DB_FILE = os.path.join(BASE_DIR, "avatar.db")
+
+engine = create_engine(
+    f"sqlite:///{DB_FILE}",
+    connect_args={"check_same_thread": False},
+)
+SessionLocal = sessionmaker(bind=engine, autoflush=False, expire_on_commit=False)
+Base = declarative_base()
+
+
+def get_db():
+    db = SessionLocal()
+    try:
+        yield db
+    finally:
+        db.close()
+
+
+def init_db():
+    import models
+
+    Base.metadata.create_all(bind=engine)
+
+    # 轻量迁移：为已存在的表补充新列（SQLite 不支持自动 ALTER，逐列尝试）
+    _try_add_columns(
+        ("qa_pairs", "enabled", "BOOLEAN DEFAULT 1"),
+        ("knowledge_docs", "vectorized", "BOOLEAN DEFAULT 0"),
+        ("knowledge_docs", "embedding_model", "VARCHAR DEFAULT ''"),
+        ("knowledge_docs", "chunk_count", "INTEGER DEFAULT 0"),
+        ("knowledge_docs", "vectorized_at", "TIMESTAMP"),
+        ("avatars", "owner_id", "VARCHAR DEFAULT ''"),
+    )
+
+
+def _try_add_columns(*cols):
+    with engine.connect() as conn:
+        for table, col, ddl in cols:
+            try:
+                conn.exec_driver_sql(f"ALTER TABLE {table} ADD COLUMN {col} {ddl}")
+                conn.commit()
+            except Exception:
+                # 列已存在（或全新库由 create_all 建好）则忽略
+                pass