diff --git a/server/db.py b/server/db.py
index 2a50230..cf06c4a 100644
--- a/server/db.py
+++ b/server/db.py
@@ -62,6 +62,7 @@ def get_db():
     conn = sqlite3.connect(DB_PATH)
     conn.row_factory = sqlite3.Row
     conn.execute("PRAGMA foreign_keys = ON")
+    conn.execute("PRAGMA busy_timeout = 5000")
     return conn
 
 
@@ -70,24 +71,19 @@ def init_db():
     conn = get_db()
     try:
         conn.executescript(SCHEMA)
+        conn.execute(
+            """
+            INSERT OR IGNORE INTO users
+              (username, password_hash, display_name, is_admin, is_active, created_at)
+            VALUES (?, ?, ?, 1, 1, ?)
+            """,
+            (
+                "admin",
+                generate_password_hash("admin123"),
+                "管理员",
+                now_iso(),
+            ),
+        )
         conn.commit()
-
-        admin = conn.execute(
-            "SELECT id FROM users WHERE username = ?", ("admin",)
-        ).fetchone()
-        if admin is None:
-            conn.execute(
-                """
-                INSERT INTO users (username, password_hash, display_name, is_admin, is_active, created_at)
-                VALUES (?, ?, ?, 1, 1, ?)
-                """,
-                (
-                    "admin",
-                    generate_password_hash("admin123"),
-                    "管理员",
-                    now_iso(),
-                ),
-            )
-            conn.commit()
     finally:
         conn.close()