{

    "openId": "OPENID",

    "nickName": "NICKNAME",

    "gender": GENDER,

    "city": "CITY",

    "province": "PROVINCE",

    "country": "COUNTRY",

    "avatarUrl": "AVATARURL",

    "unionId": "UNIONID",

    "watermark":

    {

        "appid":"APPID",

    "timestamp":TIMESTAMP

    }

}

以上是官方文档中截取的，请问，openid / nickName / city ..../ unionId 这些字段最大长度是多少？我想做一个数据库，用它来存用户信息，希望知道字段最大长度，请求大家帮忙~