Question

I’m just trying to increment a record by 1 starting at 2000, when a new record is created upon clicking on the create action to create a record:

if resource_model == Student then @resource.testing_id = id + 2000 end

So if the record has an id of 1, I assume that the testing_id will be 2001. But instead it returns:
2147483647 (maximum mysql limit?)

Any suggestions on how to address this? Thanks.

Answer 1

1. You can’t know record ID during create. ID is known after saving record do database.

2. You can’t relay on ID to give you values like 1, 2, 3 … and so on.

3. Don’t store value like ID+2000, becouse you can get it at any time by calculating id+2000.

You can get next testing_id by something like this:

if resource_model == Student then
  @resource.testing_id = Student.first(:order => "testing_id DESC").testing_id + 1
end

But if two processes at the same time will fetch the same value then you will have duplicate testing_id.