Fix database sequence errors (#4777)

* Fix database upgrade script to handle existing identity columns

Co-authored-by: jxxghp <jxxghp@live.cn>

* Improve identity column conversion with error handling and cleanup

Co-authored-by: jxxghp <jxxghp@live.cn>

* Fix database upgrade script to handle existing identity columns

Co-authored-by: jxxghp <jxxghp@live.cn>

---------

Co-authored-by: Cursor Agent <cursoragent@cursor.com>
Co-authored-by: jxxghp <jxxghp@live.cn>

database/versions/5b3355c964bb_2_2_0.py

@@ -59,7 +59,7 @@ def fix_table_sequence(connection, table_name):
 
         # 检查表是否有id列
         result = connection.execute(sa.text(f"""
-            SELECT column_name, data_type, is_nullable, column_default
+            SELECT is_identity, column_default
             FROM information_schema.columns 
             WHERE table_name = '{table_name}' 
             AND column_name = 'id'
@@ -70,10 +70,10 @@ def fix_table_sequence(connection, table_name):
             print(f"表 {table_name} 没有id列，跳过")
             return
 
-        _, _, _, column_default = id_column
+        is_identity, column_default = id_column
 
         # 检查是否已经是Identity类型
-        if column_default and 'GENERATED BY DEFAULT AS IDENTITY' in column_default:
+        if is_identity == 'YES' or (column_default and 'GENERATED BY DEFAULT AS IDENTITY' in column_default):
             print(f"表 {table_name} 的id列已经是Identity类型，跳过")
             return
 
@@ -110,4 +110,8 @@ def convert_to_identity(connection, table_name):
 
     except Exception as e:
         print(f"转换表 {table_name} 序列时出错: {e}")
+        # 如果是已经存在的Identity错误，则忽略
+        if "already an identity column" in str(e):
+            print(f"表 {table_name} 的id列已经是Identity类型，忽略此错误")
+            return
         raise