慕课 python 操作数据库

test_connection

 import MySQLdb
 
 conn = MySQLdb.Connect(
     host = '127.0.0.1',
     port = 3306,
     user = '*****',
     passwd = '*****',
     db = 'czy',
     charset = 'utf8'
     )
 
 cursor = conn.cursor()
 
 print conn
 print cursor
 
 cursor.close()
 conn.close()

结果：

<_mysql.connection open to '127.0.0.1' at 21f0980>
<MySQLdb.cursors.Cursor object at 0x0228BA30>

test_coursor：

 import MySQLdb
 
 conn = MySQLdb.Connect(
     host = '127.0.0.1',
     port = 3306,
     user = '****',
     passwd = '****',
     db = 'czy',
     charset = 'utf8'
     )
 
 cursor = conn.cursor()
 
 sql = "select * from user"
 cursor.execute(sql)
 
 print cursor.rowcount
 
 rs = cursor.fetchone()
 print rs
 
 rs = cursor.fetchmany(3)
 print rs
 
 rs = cursor.fetchall()
 print rs
 
 cursor.close()
 conn.close()

结果：

 9
 (1L, u'name1')
 ((2L, u'name2'), (3L, u'name3'), (4L, u'name4'))
 ((5L, u'name5'), (6L, u'name6'), (7L, u'name7'), (8L, u'name8'), (9L, u'name9'))

test_select:

 import MySQLdb
 
 conn = MySQLdb.Connect(
     host = '127.0.0.1',
     port = 3306,
     user = '**',
     passwd = '**',
     db = 'czy',
     charset = 'utf8'
     )
 
 cursor = conn.cursor()
 
 sql = "select * from user"
 cursor.execute(sql)
 
 rs = cursor.fetchall()
 
 for row in rs:
     print "userid = %s,username = %s" % row
 
 cursor.close()
 conn.close()

结果：

userid = 1,username = name1
userid = 2,username = name2
userid = 3,username = name3
userid = 4,username = name4
userid = 5,username = name5
userid = 6,username = name6
userid = 7,username = name7
userid = 8,username = name8
userid = 9,username = name9

test_iud:

 import MySQLdb
 
 conn = MySQLdb.Connect(
     host = '127.0.0.1',
     port = 3306,
     user = '',
     passwd = '',
     db = 'czy',
     charset = 'utf8'
     )
 
 cursor = conn.cursor()
 
 sql_insert = "insert into user(userid,username) values(10,'name10')"
 sql_update = "update user set username='name91' where userid=9"
 sql_delete = "delete from user where userd<3"
 
 try:
     cursor.execute(sql_insert)
     print cursor.rowcount 
 
     cursor.execute(sql_update)
     print cursor.rowcount 
 
     cursor.execute(sql_delete)
     print cursor.rowcount 
 
     conn.commit()
 except Exception, e:
     print e
     conn.rollback()
 
 cursor.close()
 conn.close()

结果（没有影响数据库，因为第三条语句失败了）：

1
1
(1054, "Unknown column 'userd' in 'where clause'")