Single table inheritance

Rails
1

I’m having a class called Person, with subclasses as goalkeeper,
forward, defender.

Now a person can be a forward as well as a defender or a goalkeeper.

I want to use single table inheritance like :

class Goalkeepr < Person
end

And not have multiple boolean columns like in my people table like is
is_goalkpeer, is_forward, is_defender.

How do I go about it ?

Thanks,
Pratik

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2

If you create a column ‘type’ in your table, ActiveRecord should
magically make STI work.

Tom

3

Right. I understand that. But in case of ‘type’ driven STI, a person
can just have one type. I don’t want to use HABTM with roles because I
want to seperate logic for different type of people.

I’m looking for something that lets me scope the inherited table
instead of using type field. Something like :

class Goalkeeper < Person
:scope => “type_id = 4”
end

Probably something like
http://roman2k.free.fr/rails/meantime_filter/0.1.0/rdoc/ for models.

Thanks,
Pratik

On 7/6/06, Tom W. [email protected] wrote:

Thanks,

–
email : tom at popdog.net

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“Things do not happen. Things are made to happen.” - JFK

4

On 7/6/06, Pratik [email protected] wrote:

And not have multiple boolean columns like in my people table like is
is_goalkpeer, is_forward, is_defender.

Hi Pratik,
I guess you have no way to use the STI in this scenario. I’d go with a
Person model that contains all the data except the role and create a
Role model/table.
Then Role belongs_to Person and Person has_many Roles.
Cheers.

5

On Thursday, July 06, 2006, at 10:48 PM, Francesco Levorato wrote:

francesco levorato aka flevour
http://www.flevour.net/

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For this type of thing, I use the acts_as_taggable plugin. Then you can
tag each person with each role that they fulfill and you won’t clutter
up your model with extraneous fields.

_Kevin

6

On 7/6/06, Pratik [email protected] wrote:

And not have multiple boolean columns like in my people table like is
is_goalkpeer, is_forward, is_defender.

Hi Pratik,
I guess you have no way to use the STI in this scenario. I’d go with a
Person model that contains all the data except the role and create a
Role model/table.
Then Role belongs_to Person and Person has_many Roles.
Cheers.