| 摘要 |
A method (Fig. 2), in a data processing system (Fig. 1), of imposing constraints on data files (Fig. 1, items 12, 21, 22, 23) which are changed by update statements, includes the steps (Fig. 2) of: a) identifying a particular object of the update 0x (step 30-3) and a particular attribute being updated (step 30-2); b) finding an applicable constraint (step 30-5) based on the particular attribute being updated; c) converting (step 30-6) the particular update objet 0x to at least one other object which is in the applicable constraint and is different than the update object 0x; and, d) generating an error message, if after the update, the applicable constraint is not satisfied by any object from the converting step (steps 30-7 and 30-8). |
