一、mysql 操作详解
1. 常用库
- mysql-connector-python(官方驱动)
安装:pip install mysql-connector-python - pymysql(纯 python 实现)
安装:pip install pymysql
2. 基础操作
连接数据库
import mysql.connector
config = {
'user': 'root',
'password': '123456',
'host': 'localhost',
'database': 'test_db'
}
conn = mysql.connector.connect(**config)
cursor = conn.cursor()
执行 sql
# 创建表
cursor.execute("""
create table if not exists users (
id int auto_increment primary key,
name varchar(255),
email varchar(255)
)
""")
# 插入数据
cursor.execute("insert into users (name, email) values (%s, %s)", ('alice', 'alice@example.com'))
conn.commit()
3. 高级功能
事务管理
try:
cursor.execute("insert into users (name) values ('bob')")
cursor.execute("update users set email='error' where id=999") # 模拟错误
conn.commit()
except mysql.connector.error as e:
conn.rollback()
二、oracle 操作详解
1. 常用库
- cx_oracle(官方推荐)
安装:pip install cx_oracle
依赖:需安装 oracle instant client
2. 基础操作
连接数据库
import cx_oracle
dsn = cx_oracle.makedsn("localhost", 1521, service_name="orclcdb")
conn = cx_oracle.connect(user="scott", password="tiger", dsn=dsn)
cursor = conn.cursor()
执行 sql
# 使用序列插入数据
cursor.execute("create sequence user_seq start with 1 increment by 1")
cursor.execute("""
insert into users (id, name)
values (user_seq.nextval, :name)""", name="charlie")
conn.commit()
3. 高级功能
调用存储过程
p_name = cursor.var(str)
cursor.callproc("get_user", [1, p_name])
print(p_name.getvalue()) # 输出结果
三、microsoft sql server 操作详解
1. 常用库
- pyodbc(推荐)
安装:pip install pyodbc
依赖:需安装 odbc driver - pymssql(轻量级)
安装:pip install pymssql
2. 基础操作
连接数据库
import pyodbc
conn = pyodbc.connect(
driver='{odbc driver 17 for sql server}',
server='localhost',
database='test_db',
uid='sa',
pwd='password'
)
cursor = conn.cursor()
执行 sql
# 分页查询(offset fetch)
cursor.execute("""
select * from users
order by id
offset 10 rows
fetch next 10 rows only
""")
print(cursor.fetchall())
3. 高级功能
批量插入
data = [('david', 'david@example.com'), ('eva', 'eva@example.com')]
cursor.executemany("insert into users (name, email) values (?, ?)", data)
conn.commit()
四、通用注意事项
1. 安全与性能
- 参数化查询:始终使用占位符(
%s、?、:name)避免 sql 注入。 - 连接管理:使用
with上下文管理器或封装类确保连接关闭。
# 示例:mysql 上下文管理器
with mysql.connector.connect(**config) as conn:
with conn.cursor() as cursor:
cursor.execute("select 1")
2. 异常处理
try:
conn = cx_oracle.connect("invalid_connection")
except cx_oracle.databaseerror as e:
error = e.args[0]
print(f"code: {error.code}, message: {error.message}")
finally:
if conn:
conn.close()
3. 自动化封装类
class databaseautomator:
"""通用数据库操作封装"""
def __init__(self, db_type, **config):
self.db_type = db_type
self.config = config
self.conn = none
def __enter__(self):
if self.db_type == "mysql":
self.conn = mysql.connector.connect(**self.config)
elif self.db_type == "oracle":
dsn = cx_oracle.makedsn(**self.config)
self.conn = cx_oracle.connect(user=self.config['user'], password=self.config['password'], dsn=dsn)
# 其他数据库类似
return self.conn.cursor()
def __exit__(self, exc_type, exc_val, exc_tb):
if self.conn:
if exc_type: self.conn.rollback()
else: self.conn.commit()
self.conn.close()
# 使用示例
with databaseautomator("mysql", user="root", password="123456", host="localhost", database="test_db") as cursor:
cursor.execute("select * from users")
4. orm 集成
- sqlalchemy 统一操作不同数据库:
from sqlalchemy import create_engine
# mysql
engine = create_engine("mysql+pymysql://user:password@localhost/db")
# oracle
engine = create_engine("oracle+cx_oracle://user:password@localhost:1521/orclcdb")
# sql server
engine = create_engine("mssql+pyodbc://user:password@localhost/db?driver=odbc+driver+17+for+sql+server")
with engine.connect() as conn:
result = conn.execute("select * from users")
print(result.fetchall())
通过本文档,可快速掌握 python 操作三大主流数据库的核心方法。根据场景选择合适的库和工具,结合 orm 框架可进一步提升开发效率。
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