python之数据库(mysql)操作

前言: 最近开始学django了，学了下web框架，顿时感觉又会了好多知识。happy~~ 这篇博客整理写下数据库基本操作，内容挺少。明天写SQLAlchemy。

一、数据库基本操作

1. 想允许在数据库写中文，可在创建数据库时用下面命令

create database zcl charset utf8;

2. 查看students表结构

desc students;

3. 查看创建students表结构的语句

show create table students;

4. 删除数据库

drop database zcl;

5. 创建一个新的字段

alter table students add column nal char(64);　

PS: 本人是很讨厌上面这种“简单解释+代码”的博客。其实我当时在mysql终端写了很多的实例，不过因为当时电脑运行一个看视频的软件，导致我无法Ctrl+C/V。现在懒了哈哈~~

二、python连接数据库

python3不再支持mysqldb。其替代模块是PyMySQL。本文的例子是在python3.4环境。

1. 安装pymysql模块

pip3 install pymysql

2. 连接数据库，插入数据实例

import pymysql
#生成实例，连接数据库zcl
conn = pymysql.connect(host='127.0.0.1', user='root', passwd='root', db='zcl')
#生成游标，当前实例所处状态
cur = conn.cursor()
#插入数据
reCount = cur.execute('insert into students(name, sex, age, tel, nal) values(%s, %s, %s, %s, %s)',('Jack','man',25,1351234,"CN"))
reCount = cur.execute('insert into students(name, sex, age, tel, nal) values(%s, %s, %s, %s, %s)',('Mary','female',18,1341234,"USA"))

conn.commit()  #实例提交命令

cur.close()
conn.close()
print(reCount)

查看结果:

mysql> select* from students;   　  #插入数据前
+----+-------+--------+-----+-------------+------+
| id | name  | sex    | age | tel         | nal  |
+----+-------+--------+-----+-------------+------+
|  1 | zcl   | man    |  22 | 15622341234 | NULL |
|  2 | alex  | man    |  30 | 15622341235 | NULL |
|  5 | Jack  | man    |  25 | 1351234     | CN   |
|  6 | Mary  | female |  18 | 1341234     | USA  |
| 10 | Jack  | man    |  25 | 1351234     | CN   |
| 11 | Jack2 | man    |  25 | 1351234     | CN   |
| 12 | Mary  | female |  18 | 1341234     | USA  |
+----+-------+--------+-----+-------------+------+
7 rows in set

mysql>
mysql> select* from students;　　　#插入数据后
+----+-------+--------+-----+-------------+------+
| id | name  | sex    | age | tel         | nal  |
+----+-------+--------+-----+-------------+------+
|  1 | zcl   | man    |  22 | 15622341234 | NULL |
|  2 | alex  | man    |  30 | 15622341235 | NULL |
|  5 | Jack  | man    |  25 | 1351234     | CN   |
|  6 | Mary  | female |  18 | 1341234     | USA  |
| 10 | Jack  | man    |  25 | 1351234     | CN   |
| 11 | Jack2 | man    |  25 | 1351234     | CN   |
| 12 | Mary  | female |  18 | 1341234     | USA  |
| 13 | cjy   | man    |  18 | 1562234     | USA  |
| 14 | cjy2  | man    |  18 | 1562235     | USA  |
| 15 | cjy3  | man    |  18 | 1562235     | USA  |
| 16 | cjy4  | man    |  18 | 1562235     | USA  |
| 17 | cjy5  | man    |  18 | 1562235     | USA  |
+----+-------+--------+-----+-------------+------+
12 rows in set

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学完的东西要及时总结，有些东西忘记了阿~_~