How to map a one to one relation from a legacy database when the key of one is the id of the other

Question

I'm having trouble making work a mapping for a legacy database that for me is read only, I have a class Client that belongs to ThirdParty and ThirdParty has one Client.

The tables look like this:

Client                                      ThirdParty
---------------------                       --------------------
third_party_rowid (key)                     rowid (key)

Client doesn't have its own id, and ThirdParty doesn't have a reference to Client, so when I try mapping Client I get a lot of errors:

If I try mapping both the id of Client and the ThirdParty of Client to the same column I get a duplicated column error

static mapping = {
    datasource  'xxxxx'
    table       'clients'       
    version false

    id          column: 'third_party_rowid'
    thirdParthy column: 'third_party_rowid'
    ....
}

If I try giving the id of Client the name 'thirdParhy' I get an unknown type error

static mapping = {
    datasource  'xxxxx'
    table       'clients'       
    version false

    id          name:   'thirdParthy'
    thirdParthy column: 'third_party_rowid'
    ....
}

If I try don't give id a parameter I get an invalid id error

static mapping = {
    datasource  'xxxxx'
    table       'clients'       
    version false

    thirdParthy column: 'third_party_rowid'
    ....
}   

I'm running out of ideas, can someone help me map this?

Thanks!

Answer 1

I found out the problem!, hibernate needs one of the duplicated columns to be mapped with insert="false", update="false"

To do that on grails you have to add that to the mapping, like this:

static mapping = {
    datasource  'xxxxx'
    table       'clients'       
    version false

    id          column: 'third_party_rowid'
    thirdParthy column: 'third_party_rowid', insertable: false, updateable: false
    ....
}