Python连接MySQL数据库之pymysql模块使用

返回字典格式数据：

<span style="color: #000000"># 导入pymysql模块
import pymysql
# 连接database
conn </span>= pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
# 得到一个可以执行SQL语句并且将结果作为字典返回的游标
cursor </span>= conn.cursor(cursor=<span style="color: #000000">pymysql.cursors.DictCursor)
# 定义要执行的SQL语句
sql </span>= """<span style="color: #000000">
CREATE TABLE USER1 (
id INT auto_increment PRIMARY KEY ,
name CHAR(10) NOT NULL UNIQUE,
age TINYINT NOT NULL
)ENGINE=innodb DEFAULT CHARSET=utf8;
</span>"""<span style="color: #000000">
# 执行SQL语句
cursor.execute(sql)
# 关闭光标对象
cursor.close()
# 关闭数据库连接
conn.close()</span>

注意：

charset=“utf8”，编码不要写成"utf-8"

增删改查操作

增

<span style="color: #000000"># 导入pymysql模块
import pymysql
# 连接database
conn </span>= pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
# 得到一个可以执行SQL语句的光标对象
cursor </span>=<span style="color: #000000"> conn.cursor()
sql </span>= "INSERT INTO USER1(name, age) VALUES (%s, %s);"<span style="color: #000000">
username </span>= "Alex"<span style="color: #000000">
age </span>= 18<span style="color: #000000">
# 执行SQL语句
cursor.execute(sql, [username, age])
# 提交事务
conn.commit()
cursor.close()
conn.close()</span>

插入数据失败回滚：

<span style="color: #008000">#</span><span style="color: #008000"> 导入pymysql模块</span>
<span style="color: #0000ff">import</span><span style="color: #000000"> pymysql
</span><span style="color: #008000">#</span><span style="color: #008000"> 连接database</span>
conn = pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
</span><span style="color: #008000">#</span><span style="color: #008000"> 得到一个可以执行SQL语句的光标对象</span>
cursor =<span style="color: #000000"> conn.cursor()
sql </span>= <span style="color: #800000">"</span><span style="color: #800000">INSERT INTO USER1(name, age) VALUES (%s, %s);</span><span style="color: #800000">"</span><span style="color: #000000">
username </span>= <span style="color: #800000">"</span><span style="color: #800000">Alex</span><span style="color: #800000">"</span><span style="color: #000000">
age </span>= 18
<span style="color: #0000ff">try</span><span style="color: #000000">:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 执行SQL语句</span>
<span style="color: #000000">    cursor.execute(sql, [username, age])
    </span><span style="color: #008000">#</span><span style="color: #008000"> 提交事务</span>
<span style="color: #000000">    conn.commit()
</span><span style="color: #0000ff">except</span><span style="color: #000000"> Exception as e:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 有异常，回滚事务</span>
<span style="color: #000000">    conn.rollback()
cursor.close()
conn.close()</span>

获取插入数据的ID(关联操作时会用到)

<span style="color: #008000">#</span><span style="color: #008000"> 导入pymysql模块</span>
<span style="color: #0000ff">import</span><span style="color: #000000"> pymysql
</span><span style="color: #008000">#</span><span style="color: #008000"> 连接database</span>
conn = pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
</span><span style="color: #008000">#</span><span style="color: #008000"> 得到一个可以执行SQL语句的光标对象</span>
cursor =<span style="color: #000000"> conn.cursor()
sql </span>= <span style="color: #800000">"</span><span style="color: #800000">INSERT INTO USER1(name, age) VALUES (%s, %s);</span><span style="color: #800000">"</span><span style="color: #000000">
username </span>= <span style="color: #800000">"</span><span style="color: #800000">Alex</span><span style="color: #800000">"</span><span style="color: #000000">
age </span>= 18
<span style="color: #0000ff">try</span><span style="color: #000000">:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 执行SQL语句</span>
<span style="color: #000000">    cursor.execute(sql, [username, age])
    </span><span style="color: #008000">#</span><span style="color: #008000"> 提交事务</span>
<span style="color: #000000">    conn.commit()
    </span><span style="color: #008000">#</span><span style="color: #008000"> 提交之后，获取刚插入的数据的ID</span>
    last_id =<span style="color: #000000"> cursor.lastrowid
</span><span style="color: #0000ff">except</span><span style="color: #000000"> Exception as e:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 有异常，回滚事务</span>
<span style="color: #000000">    conn.rollback()
cursor.close()
conn.close()</span>

批量执行

<span style="color: #008000">#</span><span style="color: #008000"> 导入pymysql模块</span>
<span style="color: #0000ff">import</span><span style="color: #000000"> pymysql
</span><span style="color: #008000">#</span><span style="color: #008000"> 连接database</span>
conn = pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
</span><span style="color: #008000">#</span><span style="color: #008000"> 得到一个可以执行SQL语句的光标对象</span>
cursor =<span style="color: #000000"> conn.cursor()
sql </span>= <span style="color: #800000">"</span><span style="color: #800000">INSERT INTO USER1(name, age) VALUES (%s, %s);</span><span style="color: #800000">"</span><span style="color: #000000">
data </span>= [(<span style="color: #800000">"</span><span style="color: #800000">Alex</span><span style="color: #800000">"</span>, 18), (<span style="color: #800000">"</span><span style="color: #800000">Egon</span><span style="color: #800000">"</span>, 20), (<span style="color: #800000">"</span><span style="color: #800000">Yuan</span><span style="color: #800000">"</span>, 21<span style="color: #000000">)]
</span><span style="color: #0000ff">try</span><span style="color: #000000">:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 批量执行多条插入SQL语句</span>
<span style="color: #000000">    cursor.executemany(sql, data)
    </span><span style="color: #008000">#</span><span style="color: #008000"> 提交事务</span>
<span style="color: #000000">    conn.commit()
</span><span style="color: #0000ff">except</span><span style="color: #000000"> Exception as e:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 有异常，回滚事务</span>
<span style="color: #000000">    conn.rollback()
cursor.close()
conn.close()</span>

删

<span style="color: #008000">#</span><span style="color: #008000"> 导入pymysql模块</span>
<span style="color: #0000ff">import</span><span style="color: #000000"> pymysql
</span><span style="color: #008000">#</span><span style="color: #008000"> 连接database</span>
conn = pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
</span><span style="color: #008000">#</span><span style="color: #008000"> 得到一个可以执行SQL语句的光标对象</span>
cursor =<span style="color: #000000"> conn.cursor()
sql </span>= <span style="color: #800000">"</span><span style="color: #800000">DELETE FROM USER1 WHERE id=%s;</span><span style="color: #800000">"</span>
<span style="color: #0000ff">try</span><span style="color: #000000">:
    cursor.execute(sql, [</span>4<span style="color: #000000">])
    </span><span style="color: #008000">#</span><span style="color: #008000"> 提交事务</span>
<span style="color: #000000">    conn.commit()
</span><span style="color: #0000ff">except</span><span style="color: #000000"> Exception as e:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 有异常，回滚事务</span>
<span style="color: #000000">    conn.rollback()
cursor.close()
conn.close()</span>

改

<span style="color: #008000">#</span><span style="color: #008000"> 导入pymysql模块</span>
<span style="color: #0000ff">import</span><span style="color: #000000"> pymysql
</span><span style="color: #008000">#</span><span style="color: #008000"> 连接database</span>
conn = pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
</span><span style="color: #008000">#</span><span style="color: #008000"> 得到一个可以执行SQL语句的光标对象</span>
cursor =<span style="color: #000000"> conn.cursor()
</span><span style="color: #008000">#</span><span style="color: #008000"> 修改数据的SQL语句</span>
sql = <span style="color: #800000">"</span><span style="color: #800000">UPDATE USER1 SET age=%s WHERE name=%s;</span><span style="color: #800000">"</span><span style="color: #000000">
username </span>= <span style="color: #800000">"</span><span style="color: #800000">Alex</span><span style="color: #800000">"</span><span style="color: #000000">
age </span>= 80
<span style="color: #0000ff">try</span><span style="color: #000000">:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 执行SQL语句</span>
<span style="color: #000000">    cursor.execute(sql, [age, username])
    </span><span style="color: #008000">#</span><span style="color: #008000"> 提交事务</span>
<span style="color: #000000">    conn.commit()
</span><span style="color: #0000ff">except</span><span style="color: #000000"> Exception as e:
    </span><span style="color: #008000">#</span><span style="color: #008000"> 有异常，回滚事务</span>
<span style="color: #000000">    conn.rollback()
cursor.close()
conn.close()</span>

查

查询单条数据

<span style="color: #008000">#</span><span style="color: #008000"> 导入pymysql模块</span>
<span style="color: #0000ff">import</span><span style="color: #000000"> pymysql
</span><span style="color: #008000">#</span><span style="color: #008000"> 连接database</span>
conn = pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
</span><span style="color: #008000">#</span><span style="color: #008000"> 得到一个可以执行SQL语句的光标对象</span>
cursor =<span style="color: #000000"> conn.cursor()
</span><span style="color: #008000">#</span><span style="color: #008000"> 查询数据的SQL语句</span>
sql = <span style="color: #800000">"</span><span style="color: #800000">SELECT id,name,age from USER1 WHERE id=1;</span><span style="color: #800000">"</span>
<span style="color: #008000">#</span><span style="color: #008000"> 执行SQL语句</span>
<span style="color: #000000">cursor.execute(sql)
</span><span style="color: #008000">#</span><span style="color: #008000"> 获取单条查询数据</span>
ret =<span style="color: #000000"> cursor.fetchone()
cursor.close()
conn.close()
</span><span style="color: #008000">#</span><span style="color: #008000"> 打印下查询结果</span>
<span style="color: #0000ff">print</span>(ret)

查询多条数据

<span style="color: #008000">#</span><span style="color: #008000"> 导入pymysql模块</span>
<span style="color: #0000ff">import</span><span style="color: #000000"> pymysql
</span><span style="color: #008000">#</span><span style="color: #008000"> 连接database</span>
conn = pymysql.connect(host=“你的数据库地址”, user=“用户名”,password=“密码”,database=“数据库名”,charset=<span style="color: #000000">“utf8”)
</span><span style="color: #008000">#</span><span style="color: #008000"> 得到一个可以执行SQL语句的光标对象</span>
cursor =<span style="color: #000000"> conn.cursor()
</span><span style="color: #008000">#</span><span style="color: #008000"> 查询数据的SQL语句</span>
sql = <span style="color: #800000">"</span><span style="color: #800000">SELECT id,name,age from USER1;</span><span style="color: #800000">"</span>
<span style="color: #008000">#</span><span style="color: #008000"> 执行SQL语句</span>
<span style="color: #000000">cursor.execute(sql)
</span><span style="color: #008000">#</span><span style="color: #008000"> 获取多条查询数据</span>
ret =<span style="color: #000000"> cursor.fetchall()
cursor.close()
conn.close()
</span><span style="color: #008000">#</span><span style="color: #008000"> 打印下查询结果</span>
<span style="color: #0000ff">print</span>(ret)

进阶用法

<span style="color: #008000">#</span><span style="color: #008000"> 可以获取指定数量的数据</span>
cursor.fetchmany(3<span style="color: #000000">)
</span><span style="color: #008000">#</span><span style="color: #008000"> 光标按绝对位置移动1</span>
cursor.scroll(1, mode=<span style="color: #800000">"</span><span style="color: #800000">absolute</span><span style="color: #800000">"</span><span style="color: #000000">)
</span><span style="color: #008000">#</span><span style="color: #008000"> 光标按照相对位置(当前位置)移动1</span>
cursor.scroll(1, mode=<span style="color: #800000">"</span><span style="color: #800000">relative</span><span style="color: #800000">"</span>)

Python连接MySQL数据库之pymysql模块使用

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