Difference between setValue() and updateChildren()?

Question

I have done research about setValue() and updateChildren(). I have tested both of them to add and update data from firebase database. From what I have learnt that both of them did the same exact thing and did some research about them.

From what I have learnt. The setValue() is used with a class object while updateChildren() is used with a Map or HashMap. Correct me if I'm wrong.

My question is as stated above, what is the difference between setValue() and updateChildren()?

You might find it useful to look at this question where a user was confused about data being deleted when using `setValue()`. Using setValue meant the data was replaced using only the class object provided (and so additional fields not in that class were deleted). https://stackoverflow.com/questions/44621301/android-firebase-user-specific-real-time-data-is-removed-when-user-logs-back-in#comment76267592_44621301 — Lewis McGeary, Jun 22 '17 at 23:37
@LewisMcGeary I already look up to that question and thank you very much. I think I know the difference now. — UmarZaii, Jun 23 '17 at 07:12

score 7 · Answer 1 · answered Jun 22 '17 at 21:50

7

'setValue' method is totally replacing the document (specified reference) with new data.

'updateChildren' method is just updating particular fields or add such fields if they did not exist before.

You often can get the same result using those methods, but actually they are different.

answered Jun 22 '17 at 21:50

Artem Arkhipov

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Can 'updateChildren' be used to replace document with new data? – UmarZaii Jun 22 '17 at 22:13
Yes, if you will specify new data for all fields which already exist in the document – Artem Arkhipov Jun 22 '17 at 23:22
But isn't that basically they both did the same thing and vice versa? – UmarZaii Jun 23 '17 at 06:39
Which one is faster? In my case I just update the whole database so those methods do the same thing for me. But I want to use the fastest method on my server – user924 May 31 '19 at 23:27

score 2 · Answer 2 · answered Sep 23 '19 at 20:33

Using an example where your user has fields: Name, Birthday, Favourite Colour.

Set value requires you to set all the fields under the same parent node otherwise they are overwritten with no values and deleted. However, using updateChildValue, you can specify which field you would like to update without altering other fields. And, if the field doesn't already exist, it will create a new field. This is especially useful if you just want to add a new field under the user like hair colour.

Difference between setValue() and updateChildren()?

2 Answers2