Question

In order to extract data using a query, you need to plan and define a number of issues. Which one of the following is OPTIONAL, i.e. not always required?

A. the statements you will use to extract data

B. the order in which the data will be displayed

C. the fields that you want to see in the query result

D. the tables from which you will extract the fields

Answer 1

Answer. (B) The order in which the data will be displayed.

Explanation.

A. As query is related to extract data ,it is madatory to properly define the statements which will actually select the data which is to be extracted.Those statements may or may not contain conditional clause but those have to be valid extract statements to extract the data from database.

C.There can be more one than field in a single database .If we don't define a particular field ,database system will be confused to figure out from which fields it has to select data .So those statement which does not specify particular field are not valid extract statements.

One may argue that The statement

SELECT * FROM TABLE table_name does not specify fields ,but actually '*' specify all the fields in that table

D.If you don't specify a table from which you want to extract data ,then your search space will Unviersal space.

Depending on implementation of DBMS(Data Base Management System) it may generate error or it may crash.

B.There is no madatory rule to specify the order to display data ,DBMS may display data in random order or it may display data in a paricular order depending on implementation.