diff --git a/sql_base/createtables.sql b/sql_base/createtables.sql
index e5b0787..ccb8912 100644
--- a/sql_base/createtables.sql
+++ b/sql_base/createtables.sql
@@ -1,5 +1,22 @@
-create table login_users (userid integer primary key, name varchar(50), password varchar(50));
-
-create table temp_hum_info (thid integer primary key, temperature double, humidity double, th_date_time datetime);
-
-create table record_of_operations (operid integer primary key, oper_user_name varchar(50), operation_detail text, operation_time datetime);
+-- 创建用户登录表
+create table if not exists login_users (
+    userid integer primary key,
+    name varchar(50),
+    password varchar(50)
+);
+-- 创建温湿度信息表
+create table if not exists temp_hum_info (
+    thid integer primary key,
+    temperature double,
+    humidity double,
+    th_date_time datetime
+);
+-- 创建用户操作记录表
+create table if not exists record_of_operations (
+    operid integer primary key,
+    oper_user_name varchar(50),
+    operation_detail text,
+    operation_time datetime
+);
+-- 列举显示已经创建的表
+.tables
\ No newline at end of file