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Answer 1

A:

2147483647 = 2 ^(32-1) Could you show some of your code here?

From what i'm guessing here is that you are comparing apples with strawberries :P. I think you are adding a "1" on a string so that means for example:

2000 + 1 = 20001 20001 + 1 = 200001

So if you do that a couple of times this means you will get to the maximum size of an int (21475483647). I don't know this for a 100% sure, but this has to do with the way you ask your question and the way you don't post code etc... I hope this edit was helpfull tho.

Younes 2010-02-03 13:25:06

def create_common @resource = yield params[resource_params_key] #This above just captures the user input. think of it like params[:student], and then assigns it to an instance variable @resource. if resource_model == Student then @resource.testing_id = Resource.first(:order => "testing_id DESC").testing_id + 1 end #This code above is where the problem is. If I replace Resource with resource_model (Student), then it still returns: 2147483647. I try using this: 2 ^(32-1) and it still returns 2147483647. respond_to do |format| if save_resource(@resource)

JohnMerlino 2010-02-03 14:31:53

Your comment is totaly useless. It is unreadable. If you want to add some code, please edit your question, put there your code and format it correctly (add four spaces before every code line, or use 101 button)

klew 2010-02-03 14:43:05

def create_common @resource = yield params[resource_params_key]#This above just captures the user input. think of it like params[:student], and then assigns it to an instance variable @resource.if resource_model == Student then @resource.testing_id = Student.first(:order => "testing_id DESC").testing_id + 1 end respond_to do |format|if save_resource(@resource) Hope this is more readable.

JohnMerlino 2010-02-03 14:50:57

Eh... :) Please edit your question, don't add it as a comment

klew 2010-02-03 14:52:47

Answer 2

A:

Object.idf is a (deprecated) method that returns the Ruby object ID, which uniquely identifies the object. Rails has overridden id so that in models it refers to the database primary key. I'm going to take a guess that your code snippet is from a controller, and that's why id is returning a strange and large number: It's the Ruby object id of the controller, not the primary key of the object. Give id a receiver, e.g. @resource.id, and see how that works.

Wayne Conrad 2010-02-03 13:41:12

This:if resource_model == Student then @resource.testing_id = @resource.id + 3000 endreturns this:You have a nil object when you didn't expect it!You might have expected an instance of Array.The error occurred while evaluating nil.+

JohnMerlino 2010-02-03 14:03:01

Ah, you're creating @resource. As klew said, it won't have an ID until you save it. Go with klew's answer. It's good.

Wayne Conrad 2010-02-03 14:05:30

Answer 3

+1 A:

You can't know record ID during create. ID is known after saving record do database.
You can't relay on ID to give you values like 1, 2, 3 ... and so on.
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.

klew 2010-02-03 13:55:34

This:if resource_model == Student then @resource.testing_id = Resource.first(:order => "testing_id DESC").testing_id + 1endreturns this:uninitialized constant RestfulControllerActions::InstanceMethods::ResourceWhat exactly did you mean by Resource? Note that this is centralized code, not in a specific controller but in a controller inherited by all controllers. So resource_model refers to the modelof the current controller. In this case, it's student.

JohnMerlino 2010-02-03 14:17:00

Ok, changed Resource to Student. In Rails you usualy use the same name for variable as for model from which you get records, so I automaticaly thought that you have somewhere `@resource = Resource.create` or something like this :)

klew 2010-02-03 14:40:38

Yeah, I changed it to student: if resource_model == Student then @resource.testing_id = Student.first(:order => "testing_id DESC").testing_id + 1endbut this also returns: 2147483647

JohnMerlino 2010-02-03 14:47:11

Go to your console and type: `Student.first(:order => 'testing_id DESC').testing_id` and see what it gives you. Probably you already saved some records with testing_id like `2147483647` and that's why it gives you that value again

klew 2010-02-03 14:54:18

Thanks, you were right. But what if I'm creating the very first record in the Student table: if resource_model == Student then @resource.testing_id = if Student.id == 1 2000 else Student.first(:order => "testing_id DESC").testing_id + 1 end endThis returns:You have a nil object when you didn't expect it!The error occurred while evaluating nil.testing_id

JohnMerlino 2010-02-03 15:28:11

Is there a way to check if a database has a record in the if statement?

JohnMerlino 2010-02-03 15:44:06

Alright I figured it out. I just reversed the if and else. Thanks a lot klew for helpful advice.

JohnMerlino 2010-02-03 15:51:40

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