Question

有人知道我在哪里错吗？数据库更新的语法在我看来是正确的。我也想知道是否需要关闭连接，例如在每个函数中打开和关闭连接。例如，让我们说一个函数执行不同类型的DB命令，一个函数用于插入，一个函数用于更新，一个函数用于删除，就像一个通用示例一样。

输出：

query

我的代码：

[root@localhost student_program]# python modify_student.py
Connection successful!!
Enter the id of the student record you wish to modify: 21
Is this student personal information you want to modify - y or n: y
Enter the first name: Jake
Enter the last name: Mc Intyre
Enter the email address: jake@noemail.com
Enter the address: 300 Main Street, New York
Enter the DOB in YYYY-MM-DD: 1960-01-01
Traceback (most recent call last):
  File "modify_student.py", line 38, in <module>
    modify_student()
  File "modify_student.py", line 29, in modify_student
    cur.execute(sql, [firstname, lastname, email, address, DOB, student_id])
  File "/usr/local/lib/python3.6/site-packages/pymysql/cursors.py", line 170, in execute
    result = self._query(query)
  File "/usr/local/lib/python3.6/site-packages/pymysql/cursors.py", line 328, in _query
    conn.query(q)
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 893, in query
    self._affected_rows = self._read_query_result(unbuffered=unbuffered)
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 1103, in _read_query_result
    result.read()
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 1396, in read
    first_packet = self.connection._read_packet()
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 1059, in _read_packet
    packet.check_error()
  File "/usr/local/lib/python3.6/site-packages/pymysql/connections.py", line 384, in check_error
    err.raise_mysql_exception(self._data)
  File "/usr/local/lib/python3.6/site-packages/pymysql/err.py", line 109, in raise_mysql_exception
    raise errorclass(errno, errval)
pymysql.err.ProgrammingError: (1064, "You have an error in your SQL syntax; check the manual that corresponds to your MariaDB server version for the right syntax to use near '(firstname, lastname, email, address, DOB)VALUES ('Jake','Mc Intyre','jake@noema' at line 1")

Answer 1

更新的语法是：

UPDATE tablename SET name='%s', email='%s' WHERE id='%s'

您正在尝试像INSERT一样进行更新。但是UPDATE仅支持单独设置每个列名，而不支持设置列列表。

尝试：

sql = "UPDATE students_info SET firstname='%s', lastname='%s', email='%s', address='%s', DOB='%s' WHERE ID='%s'"
cur.execute(sql, [firstname, lastname, email, address, DOB, student_id])

请参见https://mariadb.com/kb/en/library/update/

Answer 2

查询语句也不正确。试试这个

sql = 'UPDATE students_info SET firstname="'+firstname+'", lastname=="'+lastname+'", email="'+email+'", address="'+address+'", DOB="'+address+'") Where id="'+student_id+'"'

希望这会有所帮助。

Python Maria DB语法

2 个答案: