Help creating and using database


#1

I have this problem.
I have a Job table in my db, and each job has many steps (table Step).
Is not possible to know how many steps a job has until it is created. So
when I create a new job I have a problem: I can not have a step_id in my
Job table, because it can be one step or more.
What can I do?


#2

On Dec 22, 9:16 am, John S. removed_email_address@domain.invalid
wrote:

I have this problem.
I have a Job table in my db, and each job has many steps (table Step).
Is not possible to know how many steps a job has until it is created. So
when I create a new job I have a problem: I can not have a step_id in my
Job table, because it can be one step or more.
What can I do?

If jobs has_many :steps then the jobs table doesn’t have a step_id at
all: steps have a job_id column.

Fred


#3

Thanks, I know.
If I can create a job first I have no problem, but I can’t do that. I
want to be able to create a job and, at the same time, create as many
steps as I want. I would use AJAX in order to create new step fields,
but if I have not created a job I can have any relation between a step
and a job.
Any ideas?


#4

HAii… sorry my English is very bad
I don’t what you want… but I have idea
why do u not use 3 model / 3 table?

table job
id

table join_job_step
job_id
step_id

table step
id

this is “has_many_and_belongs_to” (same), but Don’t use
“has_many_and_belongs_to”.
Model:

  • job
    has_many :join_job_steps

  • join_job_step
    belongs_to :job

  • step
    has_may :join_job_steps

So, when u create job or step, u don’t need step_id or job_id… And if u
want make relation, just create join_job_step.

May be it can help u…
Thank you


Wu You Duan(Anton effendi)
Senior Rails Developer
www.kiranatama.com

On Mon, Dec 22, 2008 at 4:29 PM, John S. <


#5

I think what you’re looking for is the build method, something along
the lines of @job.steps.build in your controller.

Take a look at the complex form railscasts by Ryan B.:
http://railscasts.com/episodes/73-complex-forms-part-1
(go to parts 2 and 3 after you’re done with part 1).

On Dec 22, 5:56 am, John S. removed_email_address@domain.invalid


#6

Thanks a lot, but I think that does not solve my problem, because I need
to create a job to make a relation between the job and it steps. With
that, I can create steps without a job, but how can I make relation
between these steps and the job. Should I have to take the last steps
and make a relation with the job I am creating? I think this is a bas
solution.
Any other ideas?


#7

sorry to say, but i think what you really need is a guide on data-
modeling.

if a job has many steps, the job has to be there before you create any
steps, as every step belongs to exactly one job.

now, you say you have to create a job and its steps at the same time.
why don’t you think of a way to solve that? look into your controller,
there is always a solution.


#8

Harold wrote:

I think what you’re looking for is the build method, something along
the lines of @job.steps.build in your controller.

Take a look at the complex form railscasts by Ryan B.:
http://railscasts.com/episodes/73-complex-forms-part-1
(go to parts 2 and 3 after you’re done with part 1).

On Dec 22, 5:56�am, John S. removed_email_address@domain.invalid

Thanks a lot. I will check it.