The Grails Framework 3.3.3

(Quick Reference) ## attach ### Purpose Associates a "detached" domain instance with the current Hibernate session ### Examples
    def b = Book.get(1)
    b.title = "Blah"
    b.save(flush:true)

    b.discard()

    ...
    if (!b.isAttached()) {
        b.attach()
    }
### Description Hibernate manages persistent instances in a persistence Session. A new Session is created per request and is closed at the end of the request. If an object is retrieved from the Session and placed into a web scope such as the HttpSession it will be "detached" from the Hibernate Session once the Session is closed and discarded. You can use the `attach()` method to re-attach an existing persistent instance to the persistence Session of the current request. | Quick Reference (hide)