In database design, the concept of redundancy means __?

Question

athe elimination of certain items of data from a new system that were in the old system that preceded it.
b. that certain items of data in the database are not used.
c. that the cost of collecting certain items of data is not
justified by the benefit the data provides.
d. the duplication of certain items of data, so that they appear in two or more places on a file or in a record.

Answer 1

I'd say "D" is the answer.

Data redundancy is a data organization issue that allows the unnecessary duplication of data within your database. A change or modification, to redundant data, requires that you make changes to multiple fields of a database. While this is the expected behavior for flat file database designs and spreadsheets, it defeats the purpose of relational database designs. The data relationships, inherent in a relational database, should allow you to maintain a single data field, at one location, and make the database’s relational model responsible to port any changes, to that data field, across the database. Redundant data wastes valuable space and creates troubling database maintenance problems.

Answer 2

The answer is definitely D. It is also important to note, however, that redundancy may actually be designed INTO a relational database, in order to improve performance. It is not necessarily a bad thing, as long as its there on purpose and has been well thought out.

An example of this would be to avoid long and complicated, multiple table joins on a query that is run frequently. If the field that you require is 4-5 tables away, join wise, then it may well be more efficient to add the redundant field to the table in question instead. Erroneous (incorrect, different depending on where it is) data can be avoided by careful use of triggers (updating one instance of the record automatically updates other, redundant, instances), thus making the 'redundant' data both safe and useful.

Answer 3

In computer storage, data redundancy is a property of some disk arrays which provides fault tolerance such that if some disks fail, all or part of the data stored by the array is not lost. The cost of providing this feature is most typically increased disk space; implementations require either a duplication of the entire data set or an error-correcting code to be stored on the array.

Answer 4

I will say D. is correct. Duplication of data.
Redundancy is like a backup. You need to learn a little about RAID Drives in a computer. They can be setup many ways. One is for redundancy. You use two hard drives and every time you install or save something it save to both drives. If, one drive does a "Baked Potato" you still have everything on the other drive.

Answer 5

D. If you have a "cycalic redundancy" in a file or memory, it means that your computer has begun to copy the same information over and over. Since the file isn't made up of multiple entries of that data, it stops the file transfer/copy. When you are redundant, it means you continually repeat yourself.

Answer 6

Redundancy would communicate with: The state of being redundant or severe; a pointless repetition in language; severe wordiness. repeatedly, as interior the comparable form or way.

Answer 7

I think d. is the closest, but maybe what you mean is data is repeated in different tables. This happens when the database is not normalized (first normal form).

Answer 8

d