Is there any way to get the latest aggregate data without it being the last one in the list in Firebase?

Question

I have a list of numbers inside that have certain data, in which I am adding a value "Sí" or "No", as in this image:

The last "Sí" that I added was the one that is in number 4, but if I do a filter in Firebase with

.equalTo("Sí").limitToLast(1)

I return the value of "Sí" positioned in the number 5 and not in the 4 that was the last "Sí" that I added to the database. There is some way to recognize the last "Sí", without the need of that is in the last position of the list?

I still can not find the solution to this, I hope you can help me.

Thank you.

score 1 · Accepted Answer · answered Jun 22 '19 at 11:21

There is some way to recognize the last "Sí", without the need of that is in the last position of the list?

Yes there is. The most common approach would be to add under each object a new property of type Timestamp named lastUpdate and then query descending according to it. Everytime you update a value, change the value also to lastUpdate with the current timestamp. This is how your schema might look like:

Firebase-root
  |
  --- Users
        |
        --- 1
        |   | 
        |   --- Activo: "Si"
        |   |
        |   --- lastUpdate: 1561202277
        |
        --- 2
            | 
            --- Activo: "No"
            |
            --- lastUpdate: 1561202299

This is how to save the timestamp:

How to save the current date/time when I add new value to Firebase Realtime Database

And this is how to order descending:

Hi Alex, I use it and it works perfect. Thank you very much for your help, sorry for taking too long to respond... I was testing your idea. — Matías Nicolás Núñez Rivas, Jun 23 '19 at 15:52

Is there any way to get the latest aggregate data without it being the last one in the list in Firebase?

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