python 使用MySQL数据库的实例代码
安装pip
确认你win系统中已经安装好了python，和easy_install工具，如果系统安装成功，easy_install在目录C:\Python27\Scripts 下面
进入命令行，然后把目录切换到python的安装目录下的Script文件夹下，运行 easy_inatall pip
更新pip
CMD :python -m pip install -U pip
pip安装pymysql模块
直接使用pip安装 pip install pymysql
win64上直接在cmd中执行
连接本地数据库
使用模块pymysql连接数据库
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
|
#!/usr/bin/python
# coding=utf-8
import
pymysql
# 连接本地数据库
conn
=
pymysql.connect(host
=
'localhost'
, port
=
3306
, user
=
'root'
, passwd
=
'a123'
, db
=
'samp_db1'
, charset
=
'utf8'
)
cursor
=
conn.cursor()
cursor.execute(
'select * from bigstu'
)
for
row
in
cursor.fetchall():
print
(row)
# 查
cursor.execute(
'select id, name from bigstu where age > 22'
)
for
res
in
cursor.fetchall():
print
(
str
(res[
0
])
+
", "
+
res[
1
])
cursor.close()
print
(
'-- end --'
)
|
输出：
|
1
2
3
4
5
6
7
|
(1, '张三', '男', 24, datetime.date(2017, 3, 29), '13666665555')
(6, '小刚', '男', 23, datetime.date(2017, 3, 11), '778899888')
(8, '小霞', '女', 20, datetime.date(2017, 3, 13), '13712345678')
(12, '小智', '男', 21, datetime.date(2017, 3, 7), '13787654321')
1, 张三
6, 小刚
-- end --
|
可以直接执行sql语句。获得的结果是元组。
增
插入数据
插入一条数据，接上面的代码
|
1
2
3
4
|
insertSql
=
"insert into bigstu (name, sex, age, mobile) values ('%s','%s',%d,'%s') "
xiuji
=
(
'秀吉'
,
'男'
,
15
,
'13400001111'
)
cursor.execute(insertSql
%
xiuji)
conn.commit()
# 别忘了提交
|
添加列
在mobile后面添加一列cash
|
1
2
|
addCo
=
"alter table bigstu add cash int after mobile"
cursor.execute(addCo)
|
如果要设置默认值
|
1
2
|
addCo
=
"alter table bigstu add cash int default 0 after mobile"
cursor.execute(addCo)
|
删
删除数据
删除 name=秀吉 的数据
|
1
2
|
deleteSql
=
"delete from bigstu where name = '%s'"
cursor.execute(deleteSql
%
'秀吉'
)
|
删除列
删除cash列
|
1
2
|
dropCo
=
"alter table bigstu drop cash"
cursor.execute(dropCo)
|
改
修改数据
更新符合条件的数据
|
1
2
3
4
|
updateSql
=
"update bigstu set sex = '%s' where name = '%s'"
updateXiuji
=
(
'秀吉'
,
'秀吉'
)
# 秀吉的性别是秀吉
cursor.execute(updateSql
%
updateXiuji)
conn.commit()
|
事物处理
给某个记录的cash增加
|
1
2
3
4
5
6
7
8
9
10
|
table
=
"bigstu"
addCash
=
"update "
+
table
+
" set cash = cash + '%d' where name = '%s'"
lucky
=
(
1000
,
"秀吉"
)
try
:
cursor.execute(addCash
%
lucky)
except
Exception as e:
conn.rollback()
print
(
"加钱失败了"
)
else
:
conn.commit()
|
直接执行SQL语句，十分方便
代码片段
给数据库添加列
从json中读取需要添加的列名，获取当前2个表中所有的列名
整理得出需要插入的列名，然后将列插入到相应的表中
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
|
import
pymysql
import
json
import
os
import
secureUtils
mapping_keys
=
json.load(
open
(
"key_mapping_db.json"
,
"r"
))
db_keys
=
[]
# json中所有的key
for
k
in
mapping_keys.values():
db_keys.append(k)
conn
=
pymysql.connect(host
=
'localhost'
, port
=
3306
, user
=
'root'
,
passwd
=
'*****'
, db
=
'db_name'
, charset
=
'utf8'
)
cursor
=
conn.cursor()
table_main
=
"table_main"
main_table_keys
=
[]
# 主表的列名
cursor.execute(
"show columns from "
+
table_main)
for
row
in
cursor.fetchall():
main_table_keys.append(row[
0
])
staff_table_keys
=
[]
cursor.execute(
"show columns from table_second"
)
for
row
in
cursor.fetchall():
staff_table_keys.append(row[
0
])
need_to_insert_keys
=
[]
for
k
in
db_keys:
if
k
not
in
staff_table_keys
and
k
not
in
main_table_keys
and
k
not
in
need_to_insert_keys:
need_to_insert_keys.append(k)
print
(
"need to insert "
+
str
(
len
(need_to_insert_keys)))
print
(need_to_insert_keys)
for
kn
in
need_to_insert_keys:
print
(
"add key to db "
+
kn)
cursor.execute(
"alter table staff_table add "
+
kn
+
" text"
)
conn.close()
|
将字段字符改变
这里将main_table_keys中的所有字段改为utf8
|
1
2
3
4
5
|
# change column character set to utf8
for
co
in
main_table_keys:
change_sql
=
"alter table "
+
table_main
+
" modify "
+
co
+
" text character set utf8"
print
(change_sql)
cursor.execute(change_sql)
|
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。
原文链接：http://rustfisher.github.io/2017/05/25/Python_note/Python-mysql/?utm_source=tuicool&utm_medium=referral