Forum: Ruby on Rails having problems to map a existing schema in model classes

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Rodrigo D. (Guest)
on 2006-01-28 04:46
(Received via mailing list)
Hi, IÂ?m doing a project for a company (my first big project in rails).
The company alredy has a database schema, with lots of data, so I donÂ?t
want to change the database schema, but I donÂ?t know how to map some


Table: application
Primary Key: idapplication

Table: module
Primary Key: idmodule
Foreign Key: idapplication    References aplicattion: idapplication

Table: category
Primary Key: idcategory
Foreign Key: idapplication   References application: idapplication
Foreign Key: idmodule        References module: idmodule

An application has manies modules and a module has manies categories.
Ok, I guess thatÂ?s the easy one, the first caseÂ?

Then I have another cases, in example

Table hours:
Primary key: id
Foreign key: idpar   Refeernces: hours :id

An hour tuple has a relation with another hour tuple by the idpar key,
so in example
Hour id: 1 idpar: 2
Hour id: 2 idpar: 1

Another case:

Table user
Primay key: iduser

Table work:
Primary key: idwork
Foreign key: iduser       references user: iduser
Foreign key: idcreator    references user: iduser

So, a work has a user assigned, a user who is a creator and a user who
is an it person

Another case:

Table user:
Primary key: iduser

Table work:
Primary key: idwork

Table user_work:
Foreign key iduser references user: iduser
Foreign key idwork references work: idwork

So, a user is related to many works and a work is related to many users,
no primary key in table user_work, so I donÂ?t know what to do there

And the last one:

Table status_sir
Primary key: idstatussir

Table status_sir_next
Foreign key: idstatussir references status_sir: idstatussir
Foreign key: idstatussir_next references status_sir: idstatussir

No primary key in the table status_sir_next, so I donÂ?t know what to do,
the idea is that if you are in state 2, then you will have two tuples in
Idstatussir: 2 Idstatussir_sig: 3
Idstatussir: 2 Idstatussir_sig: 4
So now you know that if you are in state 2 you can go to state 3 or 4

Well, thatÂ?s all, I already did something, in example:

class Aplicacion < ActiveRecord::Base
            #Setear el nombre de la tabla y la primary key
            set_table_name "aplicaciones"
            set_primary_key "idaplicacion"

Sorry for the spanish, btw, I know how to set the table name and the
primary key, but I get lost when a table has not a primary key. Besides,
I donÂ?t know how to specify the relations with belong_to and has_many in
these tables, I readed some things about the :class_name, :foreign_key
and :conditions hash options but I just donÂ?t know how to use them in
those cases.

Thank you for your time

Rodrigo Domínguez
Av. Directorio 183 1º Piso
Tel: 4921-1648 / 4926-1067
Cel: 15-5695-6027
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