python-数据库编程-如何处理错误和异常（二）

import psycopg2
from psycopg2 import exceptions

try:
    # 连接到PostgreSQL数据库
    conn = psycopg2.connect(
        host="localhost",
        database="mydatabase",
        user="myusername",
        password="mypassword"
    )

    # 执行查询或命令
    cursor = conn.cursor()
    cursor.execute("SELECT * FROM mytable WHERE id = 'abc'")
    rows = cursor.fetchall()
    if not rows:
        raise exceptions.EmptyQueryError

    print(rows)

except exceptions.EmptyQueryError:
    print("查询结果为空")

except Exception as error:
    print("发生异常：{}".format(error))

finally:
    if conn:
        cursor.close()
        conn.close()