Chapter 5 Physical Database Design and Performance

Review Questions

1. Define each of the following terms:

a. File organization A technique for physically arranging the records of a file on secondary storage devices.

b. Sequential file organization Records in the file are stored in sequence according to a primary key value.

c. Indexed file organization Records are either stored sequentially or non-sequentially, and an index is created that allows software to locate individual records.

d. Hashing file organization The address for each record is determined using a hashing algorithm.

e. Denormalization The process of transforming normalized relations into unnormalized physical record specifications.

f. Composite key A key made up of more than one column.

g. Secondary key One or a combination of fields for which more than one record may have the same combination of values.

h. Data type Each unit of a detailed coding scheme recognized by system software, such as a DBMS, for representing organizational data.

i. Bitmap index A table of bits in which each row represents the distinct values of a key and each column is a bit, which when on indicates that the record for that bit column position has the associated field value.

j. Redundant Arrays of Inexpensive Disks (RAID) A set, or array, of physical disk drives that appear to the database user (and programs) as if they form one large logical storage unit.

k. Join index An index on columns from two or more tables that come from the same domain of values.

l. Stripe The set of pages on all disks in a RAID that are the same relative distance from the beginning of the disk drive.

m. Explain plan A command available in most database management systems which displays how the query optimizer will access indexes, use parallel servers and join tables to prepare query results.

2. Match the following terms to the appropriate definitions:

d bitmap index

f hashing algorithm

a...