Question

I have two domain classes:

class Contract {
    String refNo
}

class Attachment {
    byte[] data
    String mimeType
    String fileName
}

How can I set up the relationships so that I have both contractInstance.attachment and attachmentInstance.contract? I think this is bidirectional one-to-one but I’m not sure (one Contract has to have exactly one Attachment)…

Answer 1

class Contract {
    Attachment attachment
}

class Attachment {
    static belongsTo = [contract: Contract]
}

This define a 1-to-1 relationship between the two, with Contract being the owner of the relationship. This means that if you save/delete a Contract the save/delete will cascade to the Attachment, but the inverse is not true.