来自Firebase Firestore的Streambuilder，具有高级过滤功能 [英] Streambuilder from firebase firestore with advanced filtering

问题描述

基于扑朔迷离的Firebase依赖关系的新版本，有新的过滤器如isNotEqualTo，arrayContains，arrayContainsAny，whereIn等.

Based on new version of firebase dependencies in flutter, there is new filters such like isNotEqualTo, arrayContains, arrayContainsAny, whereIn and so on.

我尝试用一​​些过滤器创建streambuilder，我想获取符合这些条件的文档.

I try to create streambuilder with some filters, I want to get documents that matches these conditions.

1. "uid"字段值不等于当前uid.(isNotEqualTo)
2. 学校"字段值isEqualTo当前用户学校.(isEqualTo)
3. 随机"字段值isGreaterThanOrEqualTo应用程序生成它的随机数(isGreaterThanOrEqualTo)

stream:fireStore.collection(USERS_COLLECTION).where(UID_FIELD，isNotEqualTo:me.uid).where(SCHOOL_FIELD，isEqualTo:me.school).where(RANDOM_FIELD，isGreaterThanOrEqualTo:随机).limit(10).snapshots()，

stream: fireStore.collection(USERS_COLLECTION).where(UID_FIELD, isNotEqualTo: me.uid).where(SCHOOL_FIELD, isEqualTo: me.school).where(RANDOM_FIELD, isGreaterThanOrEqualTo: random).limit(10).snapshots(),

条件1(isNotEqualTo)对我不起作用，但是条件2和3很好用，当我添加过滤器1时，向我显示错误.

Condition 1 (isNotEqualTo) does not work with me, but 2 and 3 it's working fine, when I add the filter 1 there is error showing to me.

所有不等式(<，< =，>或> =)的过滤器都必须位于同一领域.但是您在'FieldPath([uid])'上有不等式过滤器，并且"FieldPath([random])".'package:cloud_firestore/src/query.dart':断言失败:486行pos 18:'hasInequality == field'

All where filters with an inequality (<, <=, >, or >=) must be on the same field. But you have inequality filters on 'FieldPath([uid])' and 'FieldPath([random])'. 'package:cloud_firestore/src/query.dart': Failed assertion: line 486 pos 18: 'hasInequality == field'

推荐答案

那是Firestore的限制 https://firebase.google.com/docs/firestore/query-data/查询

That is a Firestore-Limitation https://firebase.google.com/docs/firestore/query-data/queries

请注意！=查询的以下限制:

Note the following limitations for != queries:

只有给定字段存在的文档才可以匹配查询.您不能在复合查询中组合not-in和！=.在复合查询中，范围(<，< =，>，> =)和！=比较必须全部过滤在同一字段上.

Only documents where the given field exists can match the query. You can't combine not-in and != in a compound query. In a compound query, range (<, <=, >, >=) and != comparisons must all filter on the same field.

因此，您可以在uid上使用！=进行过滤，也可以在Random上使用> =进行过滤.您不能在同一查询中同时执行这两项.

So you can either filter using != on the uid OR you can filter using >= on Random. You cannot do both in the same query.

我建议您在不使用UID的情况下进行过滤，并在收到快照后让您的存储库在以后过滤掉UID.

I'd recommend filtering without the UID and let your repository filter out the UID later, once you've received the snapshots.

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