I am more confused now.  What variables are you using?  Is it _id and _auth or are you using UID and AUTH? or are they different variables being set in different places?  Or have you changed your mind about what you call them?  Are you storing something in the dataset and then reading back out more than once or just once into some vairables and then reusing those variables?  It is difficult to know the scope that things have been declared at because you have not shown the structure and declaration of the variables.

Perhaps it is time to show all the code?  Or at least all the code that references any of the variables of interest.