Firebase查询随机生成的密钥中包含的十六进制代码 [英] Firebase query hex codes contained within randomly generated keys
问题描述
我想从颜色十六进制数组中查询一个特定的孩子。
下面是我的数据库结构的快照:
如何查询特定的十六进制代码并获取其父对象的整个数组?
您无法查询列表中是否存在特定的值。这是Firebase文档建议不要在数据库中使用数组的原因之一。
但是在这种情况下(以及遇到的大多数情况),您可能会并不需要一个数组。说你只关心你的用户选择了什么颜色。在这种情况下,您可以更有效地将颜色存储为 set :
$ b
palettes
-KSmJZ .... A5I
0x474A39:true
0xbA9A7C:true
0xDEDEDF:true
0x141414:true
0x323E35 :true
I would like to query a particular child from the array of color hex codes.
Here's a snapshot of my database structure:
How do I query a particular hex code and obtain the entire array of its parent object?
You cannot query whether a specific value exists in a list. This is one of the many reasons why the Firebase documentation recommends against using arrays in the database.
But in this case (and most cases that I encounter), you may likely don't really need an array. Say that you just care about what colors your user picked. In that case, you can more efficiently store the colors as a set:
palettes
-KSmJZ....A5I
"0x474A39": true
"0xbA9A7C": true
"0xDEDEDF": true
"0x141414": true
"0x323E35": true
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