pymysql

pymysql

安装

pip install pymysql

表操作

创建表

# 导入pymysql模块
import pymysql
# 连接database
conn = pymysql.connect(host="127.0.0.1", user="root",password="root",database="test",charset="utf8")
# 得到一个可以执行SQL语句的光标对象
cursor = conn.cursor()
# 定义要执行的SQL语句
sql = """
CREATE TABLE USER1 (
id INT auto_increment PRIMARY KEY ,
name varchar (10) NOT NULL UNIQUE,
age TINYINT NOT NULL
)ENGINE=innodb DEFAULT CHARSET=utf8;
"""
# 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()

数据操作

增加

单条

# 导入pymysql模块
import pymysql
# 连接database
conn = pymysql.connect(host="127.0.0.1", user="root",password="root",database="test",charset="utf8")
# 得到一个可以执行SQL语句的光标对象
cursor = conn.cursor()
sql = "INSERT INTO USER1(name, age) VALUES (%s, %s);"
username = "pig"
age = 16
# 执行SQL语句
ret=cursor.execute(sql, [username, age])
print(ret)
# 提交事务
conn.commit()
cursor.close()
conn.close()

批量

# 导入pymysql模块
import pymysql
# 连接database
conn = pymysql.connect(host="127.0.0.1", user="root",password="root",database="test",charset="utf8")
# 得到一个可以执行SQL语句的光标对象
cursor = conn.cursor()
sql = "INSERT INTO USER1(name, age) VALUES (%s, %s);"
data = [("elephant", 18), ("dog", 20), ("cat", 21)]
try:
    # 批量执行多条插入SQL语句
    cursor.executemany(sql, data)
    # 提交事务
    conn.commit()
except Exception as e:
    # 有异常，回滚事务
    conn.rollback()
cursor.close()
conn.close()

插入时返回数据id

# 导入pymysql模块
import pymysql
# 连接database
conn = pymysql.connect(host="127.0.0.1", user="root",password="root",database="test",charset="utf8")
# 得到一个可以执行SQL语句的光标对象
cursor = conn.cursor()
sql = "INSERT INTO USER1(name, age) VALUES (%s, %s);"
username = "Alex"
age = 18
try:
    # 执行SQL语句
    cursor.execute(sql, [username, age])
    # 提交事务
    conn.commit()
    # 提交之后，获取刚插入的数据的ID
    last_id = cursor.lastrowid
    print(last_id)
except Exception as e:
    # 有异常，回滚事务
    conn.rollback()
cursor.close()
conn.close()

删除

# 导入pymysql模块
import pymysql
# 连接database
conn = pymysql.connect(host="127.0.0.1", user="root",password="root",database="test",charset="utf8")
# 得到一个可以执行SQL语句的光标对象
cursor = conn.cursor()
sql = "DELETE FROM USER1 WHERE id=%s;"
try:
    cursor.execute(sql, [3])
    # 提交事务
    conn.commit()
except Exception as e:
    # 有异常，回滚事务
    conn.rollback()
cursor.close()
conn.close()

修改

# 导入pymysql模块
import pymysql
# 连接database
conn = pymysql.connect(host="127.0.0.1", user="root",password="root",database="test",charset="utf8")
# 得到一个可以执行SQL语句的光标对象
cursor = conn.cursor()
# 修改数据的SQL语句
sql = "UPDATE USER1 SET age=%s WHERE name=%s;"
username = "tigger"
age = 80
try:
    # 执行SQL语句
    cursor.execute(sql, [age, username])
    # 提交事务
    conn.commit()
except Exception as e:
    # 有异常，回滚事务
    conn.rollback()
cursor.close()
conn.close()

查询

# 导入pymysql模块
import pymysql
# 连接database
conn = pymysql.connect(host="127.0.0.1", user="root",password="root",database="test",charset="utf8")
# 得到一个可以执行SQL语句的光标对象
cursor = conn.cursor()
# 查询数据的SQL语句
sql = "SELECT id,name,age from USER1;"
# 执行SQL语句
cursor.execute(sql)
# 获取单条查询数据
ret = cursor.fetchall()
cursor.close()
conn.close()
# 打印下查询结果
print(ret)

查询结果改为字典列表

cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)

其他

# 可以获取指定数量的数据
cursor.fetchmany(3)
# 光标按绝对位置移动1
cursor.scroll(1, mode="absolute")
# 光标按照相对位置(当前位置)移动1
cursor.scroll(1, mode="relative")