Stop duplicate primary key in table

I have checked in Bubble database allow to input duplicate the primary key, how to set it up to check to avoid it happens.

There is no primary key.

So you need to do it yourself when you add a record, just add a condition.

I am a new Bubble so please tell me detail how to add a condition?

Regards,
Long

It is in the “only When” of the Workflow Action.

In this case I have made “ID” the primary key.