Has many ( THROUGH ) confusion

Rails
1

Maybe this is normal operation, but this doesn’t seem right to me.

I have models:

  • account
    – has many listshares
    – has many lists ( through listshares )

  • list
    – has many listshares
    – has many accounts ( through listshares )

  • listshare
    –belongs to account
    –belongs to list

I would have expected that if I perform the action list.destroy, then
any records in listshares with the associated list_id would be deleted
too… but they are not.

If they should be, my model is wrong somewhere. If not, I can stop
pondering, and code the listshares tidyup manually.

Thanks

Keith

2

You need another declaration in your listshares setup:

has_many :listshares, :dependent => :destroy

In the has many through join model, Listshare is a model in its own
right and we’ll only be destroyed if you specify so in the
relationship.

Hope that helps,

Steve

3

Do you mean that the LIST model should contain

has_many :listshares, :dependent => :destroy
? ( You said listshare)

When I put that in the LIST model, it does remove listshare records
if a list is deleted, but now I’m confused about something else of
course!

I don’t always want to delete a list… sometimes I want to just remove
the relationship between a list and an account - in sql terms to
delete from listhshare where account_id = x and list_id = y.

I can’t work out how to do that ( apart from using sql )

Thanks in advance

Keith