mgo time.Time或布尔检查 [英] mgo time.Time or boolean check

问题描述

我有一个包含日期字段的mongo文档，该日期字段也可以是假的（或未定义的），并且我似乎无法找到如何检查该字段是否可用或者是否为OR或日期（时间。时间）in golang / mgo：S

I have a mongo document which contains a date field which can also be false (or not defined), and I can't seem to find how to check if the field is available OR is false OR is a date (time.Time) in golang/mgo :S

推荐答案

如果您有 time.Time 字段，并且想要知道它是否设置了有效日期，那么可以查询它的 IsZero（）方法。否则，如果您试图查询数据库中的这种文档，您可以执行以下任一操作。

If you have a time.Time field, and want to know whether it was properly set with a valid date, you can query its IsZero() method. Otherwise, if you're trying to query the database for such a document, you can do one of the following.

查询字段是否为false：

Query if the field is false:

iter := collection.Find(bson.M{"field": false}).Iter()

使用 $ exists operator ：

Query if the field is available, with the $exists operator:

iter := collection.Find(bson.M{"field": bson.M{"$exists": true}}).Iter()

使用 $ type运算符查询字段是否为日期：

Query if the field is a date, using the $type operator:

iter := collection.Find(bson.M{"field": bson.M{"$type": 9}}).Iter()

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