Firestore array contains query for list of elements

Question

I have a Firestore document that contains array like this:

Array:                    Array:
[1, 2, 3, 4, 5, 6, 7] or ['Zhangir', 'Erasyl', 'Arman']

And I need to check if this document contains any of given arrays. For Example:

[1, 2, 3, 4] or [1, 2, 7] or ['Zhangir', 'Arman'] and so on

and return it only if it has exact matches. But considering that my arrays can be 100 elements long, that would be very inconvenient to say arraycontains [1], arraycontains[2]... each time. Is there any way to do a compound query for a lot of values? All information that I found says I can't, but maybe there's a way.

From my example that would be

Firestore.instance.collection("Querys")
.where('array', arrayContains: [1, 2, 3, 4, 5]);

or

Firestore.instance.collection('Querys')
.where('array', arrayContains: ['Zhangir', 'Arman']);

and not something like

Firestore.instance.collection('Querys')
.where('array', arrayContains: 'Zhangir')
.where('array', arrayContains: 'Arman');

docRef.where("myArray", ">=", 1).where("myArray", "<=", 4); where docRef is the reference pointing to your document, and myArray is your array field within your document. More info can be found on the documentation for compound queries — sllopis
– sllopis, Commented Dec 2, 2019 at 10:02
@sloppis, it doesn't necessarily has to be 1, 2, 3, 4, it can be any given length and any given sequence, for example [3, 6] or [1, 2, 7] and so on. I updated the question — Zhangir Siranov
– Zhangir Siranov, Commented Dec 2, 2019 at 10:06
Hi @ZhangirSiranov, the previous solution would only work for a range of sequences, and you will need to create a composite index. On the other hand, for your current use case, I would suggest to use the array-contains-any operator to combine up to 10 array-contains clauses on the same field with a logical OR. More info can be found here. Notice that there is a small difference between in and array-contains-any operators, since in matches for an exact match of array length, order, and values. — sllopis
– sllopis, Commented Dec 2, 2019 at 10:38
@sllopis, but with that I will have to go through a lot of unwanted documents, increasing the size of the query. — Zhangir Siranov
– Zhangir Siranov, Commented Dec 2, 2019 at 10:41
@sllopis, because array-contains-any looks for only one element that satisfies the test — Zhangir Siranov
– Zhangir Siranov, Commented Dec 2, 2019 at 10:43

Frank van Puffelen · Accepted Answer · 2019-12-02 15:53:40Z

7

Firestore can now check for these condition on array fields:

Whether the field contains a specific value with array-contains.
Whether the field contains any of a list of (up to 10) values with array-contains-any.

What you're describing is an array-contains-all like operation, which currently doesn't exist. And you can't create it by combining multiple array-contains checks, as you can only have one of those in a query. You might want to file a feature request for it.

The best option today are to:

Pick one value from the array, and perform an array-contains query with that value. Then you do the additional filtering in your application code.
Use a map to store the values, and then use multiple where value == true conditions, as shown in the answer to this question: Firestore: Multiple 'array-contains'

answered Dec 2, 2019 at 15:53

Frank van Puffelen

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1 Comment

Zhangir Siranov Over a year ago

Thanks sir, but I'm afraid that I will have to query a lot of documents If I do it this way. I'm going to go with different solution though, but still thanks.

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