如何执行有效的布尔“假或未定义"布尔值?在解析查询? [英] How to do an efficient boolean "false or undefined" query in Parse?

问题描述

我在一个Parse实体上有一个Boolean列，我想查询所有具有明确设置为false或保留为其默认undefined值的列的行.

I have a Boolean column on one of my Parse entities, and I want to query for all rows that have this column either explicitly set to false, or left to its default undefined value.

我无法执行equalTo('myBoolColumn', false)，因为它不会返回该列具有undefined值的行.

I can't do equalTo('myBoolColumn', false), because it doesn't return rows that have an undefined value for this column.

我宁愿不使用notEqualTo('myBoolColumn', true)，因为分析文档指出，notEqualTo查询效率不高，因为它们无法利用索引.

I'd rather not do a notEqualTo('myBoolColumn', true), because the Parse documentation states that notEqualTo queries are not efficient because they can't take advantage of indexes.

文档建议改用containedIn，但是编写containedIn('myBoolColumn', [false, undefined])查询以实现预期结果感觉很错误.

The documentation suggests using containedIn instead, but it feels wrong to write a containedIn('myBoolColumn', [false, undefined]) query to achieve the expected result.

似乎notEqualTo布尔查询仍然可以建立索引，但是我没有找到可以证实这一点的权威信息，而且我不知道如何测试该查询是否使用索引.

It seems like notEqualTo boolean queries could still be indexed, but I did not find an authoritative source that confirms this, and I don't know how to test if this query uses an index or not.

那么我应该使用哪个:notEqualTo('myBoolColumn', true)或containedIn('myBoolColumn', [false, undefined])?

So which one should I use: notEqualTo('myBoolColumn', true) or containedIn('myBoolColumn', [false, undefined])?

推荐答案

您想像这样组合两个查询:

You want to combine two queries like so:

var falseQuery = new Parse.Query('YourClass');
falseQuery.equalTo('myBoolColumn', false);

var undefinedQuery = new Parse.Query('YourClass');
undefinedQuery.doesNotExist('myBoolColumn');

//this is the query you should run
var query = Parse.Query.or(falseQuery, undefinedQuery);
query.find({....});

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