–DISABLE THE ROYALTY.TRACK_ID FOREIGN KEY COLUMN — DROP (Web hosting contract)
–DISABLE THE ROYALTY.TRACK_ID FOREIGN KEY COLUMN — DROP TABLE TRACK; DROP TABLE CD; DROP TABLE BAND; CREATE TABLE TRACK AS SELECT * FROM TEMP; DROP TABLE TEMP; — –RENABLE THE ROYALTY.TRACK_ID FOREIGN KEY COLUMN, TO POINT AT THE NEW TRACK TABLE — Chapter 8 Exercise 1 solution High concurrency and real-time response to end-users are both correct answers: . Very High Concurrency Concurrency implies a very high degree of sharing of the same information. . Reaction Time Real-time, instantaneous reaction to database changes and activities are essential. If you withdraw cash from an ATM at your bank and then check your statement online in an hour or so, you would expect to see the transaction. Similarly, if you purchase something online, you would hope to see the transaction on your credit card account within minutes, if not seconds. Exercise 2 solution Very large database is the only correct answer: . Frightening Database Size Data warehouses can become incredibly large. Administrators and developers have to decide how much detail to retain, when to remove data, when to summarize, what to summarize. A lot of these decisions are done during production when the data warehouse is in use. Also, ad-hoc queries can cause serious problems because if the database is very large. User education in relation to how to code proper joins may be essential; otherwise, provision of efficiency providing structures such as pre-built joins and aggregations in materialized views can also help. Exercise 3 solution The number of tables in a join query is the best answer. Exercise 4 solution The second query is the best performing option because it finds a single record on a primary key, using the primary key index. The first option is a negative search and scans all records in the table, ignoring any indexing, searching for what is not in the table. 426 Appendix A
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