Hoffer Chapter 13

Name the type of transparency (location, replication, failure, concurrency) that is indicated by each statement.

a. End users in New York and Tulsa are updating the Engineering Parts database in San Mateo at the same time. Neither user is aware that the other is accessing the data, and the system protects the data from lost updates due to interference.

b. An end user in Tulsa deletes an item from the Standard Price List at the site. Unknown to the user, the distrib uted DBMS also deletes that item from the Standard Price List in San Mateo and New York.

c. A user in San Mateo initiates a transaction to delete a part from San Mateo parts and simultaneously to add that part to New York parts. The transaction is com pleted in San Mateo but, due to transmission failure, is not completed in New York. The distributed DBMS automatically reverses the transaction at San Mateo and notifies the user to retry the transaction. What if the distributed DBMS remembers the failed transac tion component and repeats it immediately when New York becomes available? What risks would this type of approach create?

d. An end user in New York requests the balance on hand for part number 33445. The user does not know where the record for this part is located. The distributed DBMS consults the directory and routes the request to San Mateo.