PostgreSQL: default constraint names

Question

When creating a table in PostgreSQL, default constraint names will assigned if not provided:

CREATE TABLE example (
    a integer,
    b integer,
    UNIQUE          


        

Answer 1

The manual is pretty clear about this ("tableconstraint: This form adds a new constraint to a table using the same syntax as CREATE TABLE.")

So you can simply run:

ALTER TABLE example ADD UNIQUE (a, b);