Models that reference models that occur later in the migrati


#1

Hello,

I have a relationship definition in my model definition, campaign.rb
that references another model, campaign_memberships.rb, that isn’t
created until a later migration.

has_many :active_memberships,
:class_name => “CampaignMembership”,
:foreign_key => “campaign_id”,
:conditions =>
[“campaign_memberships.campaign_membership_status_id != ?”,
CampaignMembershipStatus.find_by_code(‘resigned’).id]

When I run the migration from the beginning, it bombs out here.
What’s the best way to get around this problem?

Thanks,

Andrew


#2

removed_email_address@domain.invalid removed_email_address@domain.invalid wrote:

I have a relationship definition in my model definition, campaign.rb
that references another model, campaign_memberships.rb, that isn’t
created until a later migration.

If the problem is really the order (but I’m not convinced it is, see
below),
change the order of the migration, so that campaign_memberships happens
first. Assuming these are in the “db/migrate” directory, the way to do
this
is to name them like:

001campaign_memberships.rb
002campaign.rb

If you use the “scripts/generate migration” command to create your
migrations, the order should be sorted out for you naturally.

has_many :active_memberships,
:class_name => “CampaignMembership”,
:foreign_key => “campaign_id”,
:conditions =>
[“campaign_memberships.campaign_membership_status_id != ?”,
CampaignMembershipStatus.find_by_code(‘resigned’).id]

Also, you shouldn’t need to reference any actual model object here…
the
migrations should really be thought of as a lower level than that. You
could
make the "conditions’ an actual SQL statement like

:conditions =>
"campaign_memberships.campain_membership_status_id = " +
“(SELECT id FROM campaign_membership_status WHERE code = ‘resigned’)”

  • Tyler