This condition is defined in the form of a calculation formula. It is evaluated on each iteration carried out on the number of occurrences of the triggering field (the variable index varying from 0 to N-1, N being the dimension of the triggering field). Other than the variable index, it can reference the fields in the on-line tables, as well as the constants, the global variables, the function defined by the programmer (syntax func PROGRAMME.FONCTION).
If the result of the evaluation is not null, the update is triggered.