1
00:00:02,220 --> 00:00:10,470
Now that we had a look at a couple of operators that work nice with numbers or with changing the

2
00:00:10,470 --> 00:00:12,410
values of fields in general,

3
00:00:12,610 --> 00:00:17,320
let's have a look at some operators that work with the field itself.

4
00:00:18,010 --> 00:00:28,510
For that again, let's look into our data and let's say we want to drop the phone value on all persons who

5
00:00:28,510 --> 00:00:29,590
are sporty.

6
00:00:29,880 --> 00:00:34,390
So for this, we can again reach out to our users, update

7
00:00:34,390 --> 00:00:36,080
many users here

8
00:00:36,490 --> 00:00:39,030
and then check if isSporty is true,

9
00:00:39,040 --> 00:00:40,370
that is our condition

10
00:00:40,510 --> 00:00:42,110
and then here is what I want to change,

11
00:00:42,160 --> 00:00:45,550
I want to drop the phone value.

12
00:00:45,580 --> 00:00:54,270
Now one thing you could do is you could set phone to null, if you do that, it updated three elements and

13
00:00:54,280 --> 00:01:02,070
if you now look into your data, you'll see phone is null for everyone except Manuel who is not sporty.

14
00:01:02,720 --> 00:01:03,450
Now

15
00:01:03,460 --> 00:01:04,740
null is not

16
00:01:04,780 --> 00:01:11,450
not that though, drop does mean the field should not be there anymore but it is there, it's just null,

17
00:01:11,680 --> 00:01:14,470
so this is not the perfect solution.

18
00:01:14,470 --> 00:01:21,880
There is a special operator you can use to really get rid of a field though and that is the unset operator,

19
00:01:22,510 --> 00:01:27,910
unset allows you to well unset a field, get rid of a field. Here

20
00:01:27,920 --> 00:01:34,960
the syntax is such that you add a document as a value and then here I want to unset phone and the value

21
00:01:34,960 --> 00:01:38,420
you specify here is totally up to you.

22
00:01:38,500 --> 00:01:42,140
Typically you use an empty string but this will basically be ignored,

23
00:01:42,160 --> 00:01:48,610
the important part is the field name here and that you used unset before. If you now hit enter, three documents

24
00:01:48,610 --> 00:01:49,620
were affected

25
00:01:49,750 --> 00:01:53,290
and if we have a look into our data, there is no phone on Chris,

26
00:01:53,350 --> 00:01:55,200
there is no phone on Anna,

27
00:01:55,330 --> 00:02:00,090
there still is a phone on Manuel but Max's phone number was also dropped.

28
00:02:00,100 --> 00:02:02,220
So this is the unset operator.