MySQLdb 菜鸟笔记 1

1 打开数据库连接

conn = MySQLdb.connect( host='x.x.x.x',

                        user='xxx',

                        passwd='xxx',

                        db='xxx',

                        port=3306)

sql = 'select * from table limit 10'                       

只有port字段类型为int

2 使用cursor()方法获取操作游标

cursor = db.cursor()

2.1 fetchall返回所有的结果

2.1.1 正常输出

with conn:

    cur = conn.cursor()

    cur.execute(sql)

    rs = cur.fetchall()

    for info in rs:

        print info

输出：

(6104592L, 4L)

(214339L, 7L)

(7516522L, 7L)

(7744948L, 32L)

(9820259L, 33L)

(1420524L, 35L)

(8153528L, 38L)

(6422477L, 41L)

(3883549L, 42L)

(5919834L, 43L)

2.1.2 字典输出

with conn:

    dict_cnf = MySQLdb.cursors.DictCursor # 增加字典输出的配置项

    cur = conn.cursor(dict_cnf)

    cur.execute(sql)

    rs = cur.fetchall()

    for info in rs:

        print "id: %s ,  k:%s " %(info['id'],info['k'])

输出

id: 6104592 ,  k:4

id: 214339 ,  k:7

id: 7516522 ,  k:7

id: 7744948 ,  k:32

id: 9820259 ,  k:33

id: 1420524 ,  k:35

id: 8153528 ,  k:38

id: 6422477 ,  k:41

id: 3883549 ,  k:42

id: 5919834 ,  k:43

2.2 fetchone结果集的下一行

2.2.1 简单输出

with conn:

    cur = conn.cursor()

    cur.execute(sql)

    rs = cur.fetchone()

    print rs

输出

(6104592L, 4L)

2.2.2 测试description参数的作用（不是很理解）

with conn:

    cur = conn.cursor()

    cnt = cur.execute(sql)

    rs = cur.fetchone()

    desc = cur.description

    print desc

    print cnt # 输出查询值的数量

输出

(('id', 3, 7, 10, 10, 0, 0), ('k', 3, 2, 10, 10, 0, 0))

10

2.2.3 使用description参数配置输出，字典，跟（2.1.2 字典输出）类似

with conn:

    cur = conn.cursor()

    cur.execute(sql)

    rs = cur.fetchone()

    desc = cur.description

    cols = [col[0] for col in desc]

    rs = dict(zip(cols, rs))

    print 'id: %s    ,k:%s' %(rs['id'],rs['k'])

输出

id: 6104592    ,k:4

3 使用execute方法执行SQL语句

cursor.execute(sql)

4 关闭数据库连接

db.close()