diff --git a/backend/api/db.py b/backend/api/db.py
index e12437639b679b9e0b2dbd256802b8aeb8356354..21b1feafe54e486ad5c647df3a6c476fb5d2ba9d 100644
--- a/backend/api/db.py
+++ b/backend/api/db.py
@@ -1,4 +1,5 @@
 import pymysql
+import threading
 
 class DB:
     """
@@ -10,9 +11,9 @@ class DB:
         """
         self.db = pymysql.connect(
             user='root',
-            password='123456',
+            password='Zyl20020128',
             host='localhost',
-            db='软工管')
+            db='Digout')
         self.cursor = self.db.cursor(pymysql.cursors.DictCursor)
     def execute(self, command) -> list:
         """
@@ -85,8 +86,13 @@ class Database(DB):
         :param course: 课程名
         :return: 查询结果
         """
+        self.db.ping()
         command = "select course, time from article where uploader = '%s' order by time desc limit 2" % username
-        return self.execute(command)
+        lock = threading.Lock()
+        lock.acquire()
+        res = self.execute(command)
+        lock.release()
+        return res
     def query_course_comments(self, course) -> list:
         """
         查询特定课程的所有评论
@@ -111,7 +117,11 @@ class Database(DB):
         """
         self.db.ping()
         command = "select count(id) from comment where commenter = '%s'" % commenter
-        return self.execute(command)
+        lock = threading.Lock()
+        lock.acquire()
+        res = self.execute(command)
+        lock.release()
+        return res
     def query_user_comment_likes_number(self, commenter) -> str:
         """
         查询特定用户的所有评论
@@ -120,7 +130,11 @@ class Database(DB):
         """
         self.db.ping()
         command = "select sum(likes) from comment where commenter = '%s'" % commenter
-        return self.execute(command)
+        lock = threading.Lock()
+        lock.acquire()
+        res = self.execute(command)
+        lock.release()
+        return res
     def query_article_scores(self, id) -> list:
         """
         查询特定文章的评分