示例：常用操作

import psycopg2
import os

# 从环境变量中获取用户名和密码
user = os.getenv('user')
password = os.getenv('password')

# 创建连接对象
conn=psycopg2.connect(database="database", user=user, password=password, host="localhost", port=port)
cur=conn.cursor() #创建指针对象

# 创建连接对象（SSl连接）
conn = psycopg2.connect(dbname="database", user=user, password=password, host="localhost", port=port,
         sslmode="verify-ca", sslcert="client.crt",sslkey="client.key",sslrootcert="cacert.pem")
注意： 如果sslcert、sslkey、sslrootcert没有填写，默认取当前用户.postgresql目录下对应的client.crt、client.key、root.crt


# 创建表
cur.execute("CREATE TABLE student(id integer,name varchar,sex varchar);")

# 插入数据
cur.execute("INSERT INTO student(id,name,sex) VALUES(%s,%s,%s)",(1,'Aspirin','M'))
cur.execute("INSERT INTO student(id,name,sex) VALUES(%s,%s,%s)",(2,'Taxol','F'))
cur.execute("INSERT INTO student(id,name,sex) VALUES(%s,%s,%s)",(3,'Dixheral','M'))

# 批量插入数据
stus = ((4,'John','M'),(5,'Alice','F'),(6,'Peter','M'))
cur.executemany("INSERT INTO student(id,name,sex) VALUES(%s,%s,%s)",stus)

# 获取结果
cur.execute('SELECT * FROM student')
results=cur.fetchall()
print (results)

# 提交操作
conn.commit()

# 插入一条数据
cur.execute("INSERT INTO student(id,name,sex) VALUES(%s,%s,%s)",(7,'Lucy','F'))

# 回退操作
conn.rollback()

# 关闭连接
cur.close()
conn.close()

psycopg2常用连接方式
1. conn = psycopg2.connect(dbname="dbname", user=user, password=password, host="localhost", port=port)
2. conn = psycopg2.connect(f"dbname=dbname user={user} password={password}  host=localhost port=port")
3. 使用日志
import logging
import psycopg2
from psycopg2.extras import LoggingConnection
import os

# 从环境变量中获取用户名和密码
user = os.getenv('user')
password = os.getenv('password')

logging.basicConfig(level=logging.DEBUG) # 日志级别
logger = logging.getLogger(__name__)

db_settings = {
    "user": user,
    "password": password,
    "host": "localhost",
    "database": "dbname",
    "port": port
}

# LoggingConnection默认记录所有SQL，可自行实现filter过滤不需要的或敏感的SQL，下面给出了简单的过滤password相关SQL的示例
class SelfLoggingConnection(LoggingConnection):

    def filter(self, msg, curs):
        if db_settings['password'] in msg.decode():
            return b'queries containing the password will not be recorded'
        return msg

conn = psycopg2.connect(connection_factory=SelfLoggingConnection, **db_settings)
conn.initialize(logger)

• LoggingConnection默认记录所有SQL信息，且不会对敏感信息进行脱敏，可通过filter函数自行定义输出的SQL内容。
• 日志功能是psycopg2为了方便开发者显性调试全量SQL而提供额外功能，默认情况下不需要使用。该功能会在pyscopg2执行SQL语句前打印SQL语句，但是，需要在debug日志级别下才会输出。该功能不是默认功能，只是在有特殊需要的时候才使用，没有特别需求，不建议使用。详情参考：https://www.psycopg.org/docs/extras.html?highlight=loggingconnection