problem 1)a) With a diagram describe general distribute file service architecture.

b) With diagrams describe different navigation schemes.

problem 2)a) Describe the rules for commitment of nested transactions.

b) Describe how concurrency can be increased in locking schemes.

c) Consider optimistic concurrency control as applied to the transactions T and U defined as follows

T: x=read(i); prepare(j,44);
U: prepare (i, 55); prepare(j,66);

Assume that transactions T and U are active at the same time as one another. describe the outcome in each of the following cases.

(i) T’s request to commit comes first and backward validation is used;

(ii) U’s request to commit comes first and backward validation is used;

(iii) T’s request to commit comes first and forward validation is used;

(iv) U’s request to commit comes first and forward validation is used;

problem 3)a) With diagrams describe various types of access to a distribute database.

b) With ex describe horizontal and vertical fragmentation.