1

So I'm trying to make a favourites page in my android mobile application. The products are in their own top-level collection and structured as:

{
"Trainers": {
    "trainer1": {
        "brand": "Nike",
        "name": "Air Force 1",
        "colour": "Black"
        "url": ".................."   //FOR IMAGES

    },
    "trainer2": {
        "brand": "Adidas",
        "name": "Yeezy Boost 700",
        "colour": "Black"
        "url": ".................."   
    },
    "trainer3": {
        "brand": "Nike",
        "name": "Air Spiridons",
        "colour": "Cream"
        "url": ".................."   
    }
  }  
 }

I was then going to have another top-level collection that contains documents named as a users id, followed by an array of their favourite trainers 'name'. However, in order to populate the favourites page, I would then need to search the 'Trainer' collection for each shoe in a users favourites document.

So going back to my question, if User1 has liked 'Air Force 1 & Yeezy Boost 700' (or maybe more products than this) is it possible to query a collection where the documents 'name' field equals multiple values or is there a better way to structure a favourites activity?

Alex Mamo
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Ezan
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1 Answers1

1

is it possible to query a collection where the documents 'name' field equals multiple values or is there a better way to structure a favourites activity?

Sure it is, using an array that can contain max 10 values. According to the docs:

Similarly, use the array-contains-any operator to combine up to 10 array-contains clauses on the same field with a logical OR.

So in your case, you should use the following query:

usersRef.whereArrayContainsAny("name", Arrays.asList("Air Force 1", "Yeezy Boost 700"));
Alex Mamo
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  • Great that's what i found when searching too but is this the only way? As it then limits the users favourites to 10 rather. – Ezan Apr 07 '20 at 14:27
  • Every `get()` call on a `Query` object returns a `Task` object. You can create multiple such objects and [you can pass them to the `whenAllSuccess()` method](https://stackoverflow.com/a/50132229/5246885). That's the way can go ahead with if you need more than 10 elements. – Alex Mamo Apr 07 '20 at 14:43