Query -> Check if object exists in db

#1

Hey guys,

What’s the most performant way to check if an object exists in the database without fetching it’s data?

Currently I’m excluding all fields and using query.first().
However if I add a new field to that class I’ll have to update my code to exclude that new field too.

  1. Is there something like a query.exists()?
  2. If I want to .select(**NOTHING**), what’s the correct way to do it? (even thought this downloads some unnecessary data like _id and _created_at at least it would be easier to maintain.

Thanks in Advance.

#2

Have you tried query.select('objectId');query.first();?

1 Like
#3

Hey @davimacedo, sorry for taking so long to reply!

select("objectId") has the same effect as select("") therefore I’ll just use the 2nd approach.

However if there was a way to not get the createdAt/updatedAt/objectId data and just get a boolean result to check if the entry exists that could be useful to not waste any bandwidth.

Thanks for replying as always

#4

You could do something such as:

Parse.Query.prototype.doesExist = async function(args) {
  return !!await this.select("").first(args)
}

And then:

const exists = await new Parse.Query(Parse.User).equalTo(...).doesExist();
// exists is a bool