在Firebase中生成6位唯一编号

问题描述

我想在Firbase中生成6位唯一数字(必须为唯一)

I want to generate 6 digit unique number in Firbase (unique must)

在每个与会者新条目上，与会者代码上方应该唯一

above attendeeCode should be unique on every new attendess entry

我是Firebase的新手，我已经搜索了很多但找不到

I am new in firebase and I have searched alot but could not find

推荐答案

创建一个六位数字，该数字与与会者中的第n个条目相对应.然后在其他地方跟踪该数字.

Create a six digit number that corresponds to the nth entry into attendees. And then keep track of that number elsewhere.

您可能会在其他问题中发现Firebase仍然不支持COUNT或LENGTH个查询.

You can find in other questions that Firebase still does not support COUNT or LENGTH queries.

创建一个名为/meta-data (任意)的路径并保存当前与会者的数量:

Create a path called /meta-data (arbitrary) and save the number of current attendees:

meta-data: {
    num_of_attendees: "000000" // parse this client side and send back padded string to keep 6 characters
}

每次添加与会者时增加该值，然后递增并发送回去.这样可以避免获取所有与会者的列表并获得客户端的长度.

Grab the value every time you add an attendee, increment it, and send it back. This keeps you from grabbing a list of all attendees and getting the length client-side.

一个新选项: Firebase云功能

此功能仍处于测试阶段，但取得了一定的成功.他们在此处提供了此功能的示例:

This is still in beta, but is having fair success. They provided and example of this functionality here:

函数示例

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