how can set field value to be uniqe

yes...i want use two ajax with eachother, is it possible? if i set query validation to ajax then set code field validation to ajax, then code field validation ignored, but if i set query field validation to ajax and code field validation to non-ajax, then each of two validation will be work, one of that in ajax mode and one of that after submit.
is it possible use ajax with all of that two validation?

It's supposed to be possible to have two ajax validations, yes. Will review locally and see if they're interrupting one another, but they should not be.

Ok, looks like jQuery Validate does not support multiple remote validation rules on a single input. You will have to combine your two validations into a single ajax validation usage. To do this you'll likely just have to use Code Validation and use API to perform your database query. Have added a bug ticket to see if it's even possible to fix this, but it's not likely due to how jQuery Validate works.

forge.joomlapolis.com/issues/7957