A better example might be a field that must be unique, like a URL slug. Suppose you have a database of products and the product table has a field used for URLs,

A better example might be a field that must be unique, like a URL slug. Suppose you have a database of products and the product table has a field used for URLs, like “/tshirt” and “/sweater”. You need those to be unique within the table. The question remains - how does Marmot enforce a uniqueness constraint? If you don’t like the product example, fine, but it is easy to think of others. It would be unfortunate if marmot is incapable of supporting uniqueness.