The way you are 'supposed' to sovle this in Moodle is to put the external db's primary key value in Moodle's user.idnumber field.
syncing id with external db
This discussion has been locked because a year has elapsed since the last post. Please start a new discussion topic.
Well, I am doing that now. The problem is that I am using the External tool and when i launch it I need a way to map my userid to moodle's. The idnumber field unfortunately it not sent witht the Post back to my system..