慕课 python 操作数据库

 

test_connection

 

 1 import MySQLdb
 2 
 3 conn = MySQLdb.Connect(
 4     host = \'127.0.0.1\',
 5     port = 3306,
 6     user = \'*****\',
 7     passwd = \'*****\',
 8     db = \'czy\',
 9     charset = \'utf8\'
10     )
11 
12 cursor = conn.cursor()
13 
14 print conn
15 print cursor
16 
17 cursor.close()
18 conn.close()

 

结果：

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

 

test_coursor：

 1 import MySQLdb
 2 
 3 conn = MySQLdb.Connect(
 4     host = \'127.0.0.1\',
 5     port = 3306,
 6     user = \'****\',
 7     passwd = \'****\',
 8     db = \'czy\',
 9     charset = \'utf8\'
10     )
11 
12 cursor = conn.cursor()
13 
14 sql = "select * from user"
15 cursor.execute(sql)
16 
17 print cursor.rowcount
18 
19 rs = cursor.fetchone()
20 print rs
21 
22 rs = cursor.fetchmany(3)
23 print rs
24 
25 rs = cursor.fetchall()
26 print rs
27 
28 cursor.close()
29 conn.close()

 

结果：

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

 

test_select:

 1 import MySQLdb
 2 
 3 conn = MySQLdb.Connect(
 4     host = \'127.0.0.1\',
 5     port = 3306,
 6     user = \'**\',
 7     passwd = \'**\',
 8     db = \'czy\',
 9     charset = \'utf8\'
10     )
11 
12 cursor = conn.cursor()
13 
14 sql = "select * from user"
15 cursor.execute(sql)
16 
17 rs = cursor.fetchall()
18 
19 for row in rs:
20     print "userid = %s,username = %s" % row
21 
22 cursor.close()
23 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:

 1 import MySQLdb
 2 
 3 conn = MySQLdb.Connect(
 4     host = \'127.0.0.1\',
 5     port = 3306,
 6     user = \'\',
 7     passwd = \'\',
 8     db = \'czy\',
 9     charset = \'utf8\'
10     )
11 
12 cursor = conn.cursor()
13 
14 sql_insert = "insert into user(userid,username) values(10,\'name10\')"
15 sql_update = "update user set username=\'name91\' where userid=9"
16 sql_delete = "delete from user where userd<3"
17 
18 try:
19     cursor.execute(sql_insert)
20     print cursor.rowcount 
21 
22     cursor.execute(sql_update)
23     print cursor.rowcount 
24 
25     cursor.execute(sql_delete)
26     print cursor.rowcount 
27 
28     conn.commit()
29 except Exception, e:
30     print e
31     conn.rollback()
32 
33 
34 
35 cursor.close()
36 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\'")