Get ID of Rails Model before saving...?

Question

How do you get the id of a rails model before it is saved?

For example, if I create a new model instance, how can I get its ID before it is saved?

I know that the id is created onsave and according to the database but is there a workaround?

Answer 1

I was looking for this too, and I found an answer:

Let's suppose model name is "Model" and table name is "models"

model.rb

before_save {
    next_id=Model.connection.select_value("Select nextval('models_id_seq')")
}

This will output the value your record will take for id IF it gets saved

Answer 2

Usually when people think they need to do this they actually do not need to do it. Like John says, explain what you are trying to do and someone can probably suggest a way to do it without having to know the id in advance.