我正在尝试使用postgreSQL设置我的discord机器人的自定义前缀，并使用python作为前端

import psycopg2

conn = psycopg2.connect(database="your_database", user="your_username", password="your_password", host="your_host", port="your_port")

cur = conn.cursor()
cur.execute("CREATE TABLE IF NOT EXISTS prefixes (guild_id VARCHAR PRIMARY KEY, prefix VARCHAR)")
conn.commit()

# 设置前缀
def set_prefix(guild_id, prefix):
    cur = conn.cursor()
    cur.execute("INSERT INTO prefixes (guild_id, prefix) VALUES (%s, %s) ON CONFLICT (guild_id) DO UPDATE SET prefix = %s", (guild_id, prefix, prefix))
    conn.commit()

# 获取前缀
def get_prefix(guild_id):
    cur = conn.cursor()
    cur.execute("SELECT prefix FROM prefixes WHERE guild_id = %s", (guild_id,))
    result = cur.fetchone()
    if result:
        return result[0]
    else:
        return "!"  # 默认前缀

conn.close()