Introduction to SQL - Technical MCQs

Q1:

A view is which of the following?

A A virtual table that can be accessed via SQL commands

B A virtual table that cannot be accessed via SQL commands

C A base table that can be accessed via SQL commands

D A base table that cannot be accessed via SQL commands

ANS:A - A virtual table that can be accessed via SQL commands

Views can represent a subset of the data contained in a table. Consequently, a view can limit the degree of exposure of the underlying tables to the outer world: a given user may have permission to query the view while denied access to the rest of the base table.

Views can join and simplify multiple tables into a single virtual table.

Views can act as aggregated tables, where the database engine aggregates data (sum, average, etc. ) and presents the calculated results as part of the data.

Views can hide the complexity of data. For example, a view could appear as Sales2000 or Sales2001, transparently partitioning the actual underlying table.

Views take very little space to store; the database contains only the definition of a view, not a copy of all the data that it presents.

Depending on the SQL engine used, views can provide extra security.