python针对mysql数据库的连接、查询、更新、删除操作示例

            
import pymysql
# 打开数据库连接
db = pymysql.connect("localhost","root","root","db_test01" )
# 使用 cursor() 方法创建一个游标对象 cursor
cursor = db.cursor()
# 使用 execute() 方法执行 SQL 查询 
cursor.execute("SELECT VERSION()")
# 使用 fetchone() 方法获取单条数据.
data = cursor.fetchone()
print ("Database version : %s " % data)
# 关闭数据库连接
db.close()


          

            
import pymysql
# 打开数据库连接
db = pymysql.connect("localhost","root","root","db_test01" )
# 使用cursor()方法获取操作游标 
cursor = db.cursor()
# SQL 查询语句
sql = "SELECT * FROM EMPLOYEE \
    WHERE INCOME > '%d'" % (1000)
try:
  # 执行SQL语句
  cursor.execute(sql)
  # 获取所有记录列表
  results = cursor.fetchall()
  for row in results:
   fname = row[0]
   lname = row[1]
   age = row[2]
   sex = row[3]
   income = row[4]
    # 打印结果
   print ("fname=%s,lname=%s,age=%d,sex=%s,income=%d" % \
       (fname, lname, age, sex, income ))
except:
  print ("Error: unable to fetch data")
# 关闭数据库连接
db.close()


          

            
import pymysql
# 打开数据库连接
db = pymysql.connect("localhost","root","root","db_test01" )
# 使用cursor()方法获取操作游标 
cursor = db.cursor()
# SQL 更新语句
sql = "UPDATE EMPLOYEE SET AGE = AGE + 1 WHERE SEX = '%c'" % ('M')
try:
  # 执行SQL语句
  cursor.execute(sql)
  # 提交到数据库执行
  db.commit()
  print("update OK")
except:
  # 发生错误时回滚
  db.rollback()
# 关闭数据库连接
db.close()


          

            
import pymysql
# 打开数据库连接
db = pymysql.connect("localhost","root","root","db_test01" )
# 使用cursor()方法获取操作游标 
cursor = db.cursor()
# SQL 删除语句
sql = "DELETE FROM EMPLOYEE WHERE AGE > '%d'" % (20)
try:
  # 执行SQL语句
  cursor.execute(sql)
  # 提交修改
  db.commit()
  print("delete OK")         
except:
  # 发生错误时回滚
  db.rollback()
# 关闭连接
db.close()