What are you doing?

currently I've a function returning x number of digits that are randomly generated: 324322, 28393, 3294329, 928593, 032293,..... so on. I need them to be unique as well. I've unique constraint on the field. My question is would sequelize try again if unique constraint fails?? If not then what is the good way to fix this as I can't make value really long to prevent collisions.