1. A method for finding an optimal set of data association rules in automated data diagnosis of the data characterizing an entity, comprising the steps of: establishing a computer system for automated data diagnoses; creating in said computer system a relation R containing the data A=(A 1 ,. .. , A n , A n+1 ,. .. A n+m ), where n, m≧1, said data characterizing the entity to be diagnosed, said data being represented by outcome attributes A n+1 ,. .. A n+m and by diagnosable attributes A 1 ,. .. A n , said outcome attributes determining whether the entity is desirable or not, and said diagnosable attributes determining the reason of why the entity is desirable or not; specifying a selection outcome condition (D) determined by a user which includes strictly outcome attributes selected from said A n+1 ,. .. A n+m attributes; specifying at least one diagnosable selection condition (C) which includes diagnosable attributes selected by the user from said A 1 ,. .. A n attributes; specifying selection condition constraints (S) for said diagnosable selection conditions to meet, said selection condition constraints (S) including minimal acceptable confidence conf(c), minimal acceptance support sup(c) and maximum order of said diagnosable selection condition; specifying a number of fringes of interest, F 0 , F 1. .. F i , F i+1 , wherein F 0 = ⁢ { C | up ⁡ ( C ) = 0 } F i + 1 = ⁢ { C | up ⁡ ( C ) ⊆ ⋃ j ≤ i ⋀ C ′ ⁢ ε ⁢ ⁢ F ′ } and wherein the fringe F 0 represents an optimal set of selection conditions with regard to a combination of respective ones of said specified support, said specified confidence and said specified simpler-than ordering, the fringe F 1 , represents the set of diagnosable selection conditions that are less desirable than the fringe F 0 , and the fringe F i+1 represents the set of diagnosable selection conditions that are less desirable than fringe F i ; computing said optimal fringes F 0 , F 1 ,. .. F i , F i+1 ; computing a compact set of said optimal fringes to eliminate redundant conditions, said compact set representing the optimal set of data association rules; and storing said compact set of said optimal fringes in a memory of said computer system for retrieval.