Firebase分页数据.可能吗? [英] Firebase paging data. Is it possible?

问题描述

我有一个基本上可以从Firebase读取数据的功能.我正在尝试实现分页.请看看我尝试了什么.我在该网站上看到过其他帖子，但它们不是很清楚.

I have a function which basically reads data from firebase. I am trying to implement paging. Please see what i tried. I have seen other posts on this website but they are not very clear.

  getFormData(pageSize:number,pageIndex:number,af:AngulrFireDatabase) {

      Try1: Returning all records
      ---------------------------- 
         return this.af.list('/forms').skip(pageIndex*pageSize).take(pageSize);


      Try2: Not sure how to use the previous page last key value to pass to load the next page data. 
      -----------------------------

            return this.af.list('/forms', {
                query: {
                    orderByKey: true,
                    limitToFirst:pageSize 
                    // How to skip the first few records here. for example if the page index is 2 then i have to ignore the first 2 pages data.
                }
            })

  }

任何建议都将通过基本的代码示例得到赞赏.谢谢.

Any suggestions would be appreciated with a basic code example. Thank you.

推荐答案

您不能跳过特定数量的记录.但是您可以通过指定 startAt:"keyAtWhichToStart" 来告诉Firebase从哪个项目开始.

You can't skip a specific number of records. But you can tell Firebase at which item to start by specifying startAt: "keyAtWhichToStart".

之所以没有基于偏移量的查询，是因为它们在实时更新的环境中无法正常运行，这正是Firebase数据库的设计目的.

The reason for not having offset based queries is that they don't work well in the context of realtime updates, which is what the Firebase Database was designed for.

我还建议您阅读许多上一页Firebase实时数据库中有关分页的问题.

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