How to create unique constraint in Elasticsearch database?

Question

I am using elasticsearch as a document database and each record I create has a guid id that the system uses for the record id. Business people want to offer a feature to let

Answer 1

You'd need to use the field that is supposed to be unique as id for your documents. By default a new document with existing id would override the existing document with same id, but you can switch to op_type=create in order to get back an error if a document with same id already exists.

There's no way to have the same behaviour with arbitrary fields though, only the _id field works that way. I would probably consider handling this logic in the application layer instead of within elasticsearch.