Can domain classes be configured to insert a new record instead of updating when saved?

When I change a domain object, rather than updating the database record, I'd like to archive the old record record and create a new one. I'd like to force GORM to do this automatically.

For example, if I had this domain class:

class User {
    String username
    String email
    Boolean active
}

then I'd like

user.email = email
user.save()

to开发者_如何转开发 set the active flag on the user to false, keeping a record of the old email. A new record with the new email address and active = true would be inserted.

Is this a common pattern? Is it easy to do in the domain class so that it happens transparently?

You can use GORM event beforeUpdate into User domain class (see the documentation here and here) with something like the following should work (not tested) :

def beforeUpdate() {
  if (isDirty('email') { //enters only if email was changed. Works only with Grails 1.3.x
  User.withNewSession {
    //Create the new entry
    new User(username:username, email:email).save()
    //Update the old entry with the old email value
    email = getPersistentValue('email')
  }
  }
}

One option I can think of would be to implement a soft delete and then persist a new user. I realize this is not exactly what you're asking for but I don't know how to do this with a single save. Not ideal IMO.

Another (probably better) approach would be to use Hibernate Envers to "version" the User entity and keep an history of changes. I don't know the exact status of Envers with Grails but it looks like there is a plugin for it. See also [grails-user] GORM & Envers / Audit History Tables.