about `save` method and model's id

[class4cxy]

hi :

my question is after i call the model.save() method, how can i get the current model's id ? and mysql db is design to auto_increment.
i was try to use "SELECT LAST_INSERT_ID() as id FROM " after save's callback, but it dosen't suit when concurrent request

[mde]

Once the save callback has executed, the instance you created should have its id property correctly assigned.

[class4cxy]

thanks for reply.
you means i can get the id from model instance ?
like this ?
var user = User.create(params);
user.save(function () { alert(user.id) })

[class4cxy]

i found the insertId was return throught this.exec(sql, function (err, res) { ,but it dosen't return back to callback, why ? how could i get the insertId