# How to ignore :type in some cases? (when I don't want STI)

**URL:** <https://www.ruby-forum.com/t/how-to-ignore-type-in-some-cases-when-i-dont-want-sti/104175>\
**Category:** Rails\
**Created:** [May 15, 2007, 1:19am UTC](https://www.ruby-forum.com/t/how-to-ignore-type-in-some-cases-when-i-dont-want-sti/104175 "2007-05-15T01:19:34Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![fraser\_c](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/f9ae1b/32.png) [@fraser\_c](https://www.ruby-forum.com/u/fraser_c)\
**Post date:** [May 15, 2007, 1:19am UTC](https://www.ruby-forum.com/t/how-to-ignore-type-in-some-cases-when-i-dont-want-sti/104175/1 "2007-05-15T01:19:34Z")

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Hi,

I have a model Member containing details such as name, address, phone,  
etc.  
There are various approval stages for new and changed members so I need  
a few  
extra models based on member, some can use STI, some I’d prefer not to  
use  
STI.

MemberMod which stores a modified member in the members table using STI.  
This  
is necessary because there are approval stages to a modification. This  
is  
working fine and the simplified model looks like this:

class MemberMod \< Member  
belongs\_to :original\_member, :class\_name =\> ‘Member’,  
:foreign\_key =\> :original\_member\_id  
end

I have a few other models that are very similar to MemberMod (such as  
MemberTransfer) which should have no problem using the STI method,  
however …

I’m now creating a MemberProposal model which needs all the fields of a  
Member  
and a bunch more. I was planning to use a member\_proposals table for  
the  
extra details but to store the routine member details in the members  
table  
(to avoid duplicating it all) - however I need the record in members  
table to  
be easily recognizable as a “proposed member” not a “member” - I have  
issues,  
here’s the simplified model:

class MemberProposal \< ActiveRecord::Base  
# most details we store in a member record with type set to  
MemberProposal  
belongs\_to :member  
end

The issue is that when I try to access models that belong\_to member it  
fails,  
things like:

member\_proposal.member.club  
member\_proposal.member.state  
member\_proposal.member.country

It fails because it thinks Member is a MemberProposal and not a Member  
(technically I suppose it’s correct). Is there any way to turn off the  
magic  
interpretation of member[:type] for this use case or do I need to change  
my  
scheme entirely?

## Thanks

Fraser C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Georgetown, Ontario, Canada

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<div class="post-metadata">

**Author:** ![fraser\_c](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/f9ae1b/32.png) [@fraser\_c](https://www.ruby-forum.com/u/fraser_c)\
**Post date:** [May 15, 2007, 2:57pm UTC](https://www.ruby-forum.com/t/how-to-ignore-type-in-some-cases-when-i-dont-want-sti/104175/2 "2007-05-15T14:57:58Z")

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> I have a model Member containing details such as name, address, phone, etc.  
> There are various approval stages for new and changed members so I need a few  
> extra models based on member, some can use STI, some I’d prefer not to use  
> STI.

> It fails because it thinks Member is a MemberProposal and not a Member  
> (technically I suppose it’s correct). Is there any way to turn off the magic  
> interpretation of member[:type] for this use case or do I need to change my  
> scheme entirely?

I’d consider re-architecting your design. Creating new member-like  
models for members with different approval stages seems clunky to me.  
How about simply having Member and ApprovalStage models, so that you  
can find members by approval stage?

---

<div class="post-metadata">

**Author:** ![fraser\_c](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/f9ae1b/32.png) [@fraser\_c](https://www.ruby-forum.com/u/fraser_c)\
**Post date:** [May 19, 2007, 7:36pm UTC](https://www.ruby-forum.com/t/how-to-ignore-type-in-some-cases-when-i-dont-want-sti/104175/3 "2007-05-19T19:36:06Z")

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On Tuesday 15 May 2007 08:56:27 Mark T. wrote:

> I’d consider re-architecting your design. Creating new member-like  
> models for members with different approval stages seems clunky to me.  
> How about simply having Member and ApprovalStage models, so that you  
> can find members by approval stage?

First thanks for reply. Yes, I realized I was going down a very dark  
road the  
more I thought about this. STI provides just a little too much magic (I  
had  
already hacked around it for a few cases). I think abstract classes are  
the  
way to go:

- MemberDetails = abstract class (no table) base for all other types of  
member
- Member = regular member
- MemberProposal = mostly like a member but with some extra detail
- MemberMod = all fields of a member plus pointer to the original member
- MemberTransfer = similar to MemberMod

By using an abstract base class all my validations can be in the single  
model  
and I can continue to use all of the code I’ve developed without change  
(a  
nice bonus).

I had wanted to avoid having multiple very similar tables but the more I  
think  
about it I don’t see a problem with it.

–  
Fraser C. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid)  
Georgetown, Ontario, Canada