如何在MySQL中实现数据的分片和负载均衡？

import mysql.connector

# 创建数据库连接
cnx = mysql.connector.connect(user='username', password='password', host='host_address', database='database_name')

# 创建游标对象
cursor = cnx.cursor()

# 创建分片规则（假设按照用户ID分片）
shard_rules = {
    'shard1': (0, 1000),
    'shard2': (1001, 2000)
}

# 插入数据的方法
def insert_data(user_id, name, email):
    shard = get_shard(user_id)
    insert_query = "INSERT INTO users (user_id, name, email) VALUES (%s, %s, %s)"
    cursor.execute(insert_query, (user_id, name, email))
    cnx.commit()

# 获取分片的方法
def get_shard(user_id):
    for shard, (start, end) in shard_rules.items():
        if user_id >= start and user_id <= end:
            return shard
    raise Exception("Invalid user ID")

# 查询数据的方法
def query_data(user_id):
    shard = get_shard(user_id)
    query = "SELECT * FROM users WHERE user_id = %s"
    cursor.execute(query, (user_id,))
    result = cursor.fetchall()
    return result

# 关闭游标和连接
cursor.close()
cnx.close()