The dynamics of belief and knowledge is one of the major components of any autonomous system that should be able to incorporate new pieces of information. We show that knowledge base dynamics has interesting connection with kernel change via hitting set and abduction. The approach extends and integrates standard techniques for efficient query answering and integrity checking. The generation of hitting set is carried out through a hyper tableaux calculus and magic set that is focused on the goal of minimality. Many different view update algorithms have been proposed in the literature to address this problem. The present paper provides a comparative study of view update algorithms in rational approach. ⋆ This paper extends work from Delhibabu [34] and Mayol [83] Our knowledge base dynamics is defined in two parts: an immutable part (formulae) and updatable part (literals) (for definition and properties see works of Nebel [88] and Segerberg [98]). Knowledge bases have a set of integrity constraints (see the definitions in later section). In the case of finite knowledge bases, it is sometimes hard to see how the update relations should be modified to accomplish certain knowledge base updates.Example 1. Consider a database with an (immutable) rule that a staff member is a person who is currently working in a research group under a chair. Additional (updatable) facts are that matthias and gerhard are group chairs, and delhibabu and aravindan are staff members in group info1. Our first integrity constraint (IC) is that each research group has only one chair ie. ∀x, y, z (y=x) ← group chair(x,y) ∧ group chair(x,z). Second integrity constraint is that a person can be a chair for only one research group ie. ∀x, y, z (y=z)← group chair(y,x) ∧ group chair(z,x).Immutable part: staff chair(X,Y)← staff group(X,Z),group chair(Z,Y). Updatable part: group chair(infor1,matthias)← group chair(infor2,gerhard)← staff group(delhibabu,infor1)← staff group(aravindan,infor1)← Suppose we want to update this database with the information, staff chair(aravindan,gerhard); From the immutable part, we can deduce that this can be achieved by asserting staff group(aravindan,Z) group chair(Z,gerhard)If we are restricted to definite clauses, there are three plausible ways to do this: first case is, aravindan and gerhard belong to infor1, i.e, staff group(aravindan,-info1) group chair(info1,gerhard). We need to delete both base facts group chair-(infor1,matthias)← and group chair(infor2,gerhard)←, because our first IC as well as second IC would be violated otherwise. In order to change the view, we need to insert group chair(infor1,gerhard)← as a base fact. Assume that we have an algorithm that deletes the base facts staff group(delhibabu,infor1)← from the database. But, no rational person will agree with such an algorithm, because the fact staff group(delhibabu,infor1)← is not "relevant" to the view atom.Second case, aravindan and gerhard belong to infor2, that is staff group(aravindan,info2) group chair(info2,gerhard). Simply, insert the new fact ...