class Book {
    ...
    static mapping = {
        autoTimestamp false
    }
}autoTimestamp
Purpose
Disables auto timestamping when set to false
Examples
Description
Usage: autoTimestamp(boolean)
By default when you have properties called dateCreated and/or lastUpdated in a domain class, Grails automatically maintains their state in the database. You can disable this by setting autoTimestamp to false:
static mapping = {
    autoTimestamp false
}