修复init初始化异常

backend/app/main.py

@@ -2,6 +2,7 @@ from contextlib import asynccontextmanager
 
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
+from sqlalchemy import text
 
 from app.api.v1.router import api_router
 from app.core.config import settings
@@ -18,12 +19,46 @@ async def lifespan(_: FastAPI):
 
     if settings.ENV == "development":
         async with engine.begin() as conn:
+            await _ensure_legacy_primary_keys(conn)
             await conn.run_sync(Base.metadata.create_all)
         async with SessionLocal() as session:
             await ensure_admin_exists(session)
     yield
 
 
+async def _ensure_legacy_primary_keys(conn) -> None:
+    # Fix legacy databases where tables with an "id" column were created without a PK.
+    result = await conn.execute(
+        text(
+            """
+            SELECT c.relname AS table_name
+            FROM pg_class c
+            JOIN pg_namespace n ON n.oid = c.relnamespace
+            WHERE n.nspname = 'public'
+              AND c.relkind = 'r'
+              AND EXISTS (
+                  SELECT 1
+                  FROM pg_attribute a
+                  WHERE a.attrelid = c.oid
+                    AND a.attname = 'id'
+                    AND a.attisdropped = false
+              )
+              AND NOT EXISTS (
+                  SELECT 1
+                  FROM pg_constraint con
+                  WHERE con.conrelid = c.oid
+                    AND con.contype = 'p'
+              )
+            """
+        )
+    )
+    tables = [row.table_name for row in result.fetchall()]
+    for table_name in tables:
+        await conn.execute(
+            text(f'ALTER TABLE "{table_name}" ADD CONSTRAINT "{table_name}_pkey" PRIMARY KEY (id)')
+        )
+
+
 def create_app() -> FastAPI:
     app = FastAPI(
         title="CTMS 后端 API",