Database - Physical Database Design
Database - Physical Database Design
11. A secondary key is which of the following?
- Nonunique key
- Primary key
- Useful for denormalization decisions
- Determines the tablespace required
12. The fastest read/write time and most efficient data storage of any disk array type is:
- RAID-0.
- RAID-1.
- RAID-2.
- RAID-3.
13. A rule of thumb for choosing indexes for a relational database includes which of the
following?
following?
- Indexes are more useful on smaller tables.
- Indexes are more useful for columns that do not appear frequently in the WHERE clause in queries.
- Do not specify a unique index for the primary key of each table.
- Be careful indexing attributes that have null values.
14. Sequential retrieval on a primary key for sequential file storage has which of the following
features?
features?
- Very fast
- Moderately fast
- Slow
- Impractical
15. A multidimensional database model is used most often in which of the following models?
- Data warehouse
- Relational
- Hierarchical
- Network
16. What type of join is needed when you wish to include rows that do not have matching values?
- Equi-join
- Natural join
- Outer join
- All of the above.
17. What type of join is needed when you wish to return rows that do have matching values?
- Equi-join
- Natural join
- Outer join
- All of the above.
18. Which of the following is true concerning a procedure?
- You do not create them with SQL.
- They do not need to have a unique name.
- They include procedural and SQL statements.
- They are the same thing as a function.