MySQL Connector/Python 發行說明
以下範例腳本將為所有在 2000 年加入公司且目前仍在職的員工,提供自明天起生效的 15% 加薪。
為了迭代選定的員工,我們使用緩衝游標。(緩衝游標在執行查詢後擷取並緩衝結果集的列;請參閱第 10.6.1 節,「cursor.MySQLCursorBuffered 類別」。)這樣一來,就不需要在新的變數中擷取列。相反地,游標可以當作迭代器使用。
注意
此腳本僅為範例;還有其他方法可以完成這個簡單的任務。
from __future__ import print_function
from decimal import Decimal
from datetime import datetime, date, timedelta
import mysql.connector
# Connect with the MySQL Server
cnx = mysql.connector.connect(user='scott', database='employees')
# Get two buffered cursors
curA = cnx.cursor(buffered=True)
curB = cnx.cursor(buffered=True)
# Query to get employees who joined in a period defined by two dates
query = (
"SELECT s.emp_no, salary, from_date, to_date FROM employees AS e "
"LEFT JOIN salaries AS s USING (emp_no) "
"WHERE to_date = DATE('9999-01-01')"
"AND e.hire_date BETWEEN DATE(%s) AND DATE(%s)")
# UPDATE and INSERT statements for the old and new salary
update_old_salary = (
"UPDATE salaries SET to_date = %s "
"WHERE emp_no = %s AND from_date = %s")
insert_new_salary = (
"INSERT INTO salaries (emp_no, from_date, to_date, salary) "
"VALUES (%s, %s, %s, %s)")
# Select the employees getting a raise
curA.execute(query, (date(2000, 1, 1), date(2000, 12, 31)))
# Iterate through the result of curA
for (emp_no, salary, from_date, to_date) in curA:
# Update the old and insert the new salary
new_salary = int(round(salary * Decimal('1.15')))
curB.execute(update_old_salary, (tomorrow, emp_no, from_date))
curB.execute(insert_new_salary,
(emp_no, tomorrow, date(9999, 1, 1,), new_salary))
# Commit the changes
cnx.commit()
cnx.close()