Practice Database Redesign Multiple Choice Questions with Answers Quiz-2

Q.1.

Database redesign is especially difficult if the database has no data.

True
False

Q.2.

Some organizations take the stand that no application should ever employ the true name of a table.

True
False

Q.3.

A tool that can help designers understand the dependencies of database structures is a:

dependency graph.
data model.
graphical display.
None of the above is correct.

Q.4.

How many copies of the database schema are typically used in the redesign process?

One
Two
Three
Four

Q.5.

Because of the importance of making data model changes correctly, many professionals are ________ about using an automated process for database redesign.

optimistic
skeptical
ambivalent
None of the above is correct

Q.6.

The EXISTS keyword will be true if:

any row in the subquery meets the condition only.
all rows in the subquery fail the condition only.
both of these two conditions are met.
neither of these two conditions is met.

Q.7.

Changing cardinalities in a database is:

a common database design task.
a rare database design task, but does occur.
a database design task that never occurs.
is impossible to do, so a new database must be constructed and the data moved into it.

Q.8.

The NOT EXISTS keyword will be true if:

any row in the subquery meets the condition.
all rows in the subquery fail the condition.
both of these two conditions are met.
neither of these two conditions is met.

Q.9.

The data model that is produced from reverse engineering is:

a conceptual model.
an internal model.
a logical model.
None of the above is correct.

Q.10.

To drop a column that is used as a foreign key, first:

drop the primary key.
drop the table containing the foreign key.
drop the foreign key constraint.
All of the above must be done.

Q.11.

Before any changes to database structure are attempted one should first:

clearly understand the current structure and contents of the database only.
test any changes on a test database only.
create a complete backup of the operational database only.
All of the above should be done.

Q.12.

Which of the following modifications may not succeed?

Changing a column data type from char to date
Changing a column data type from numeric to char
Both of the above actions should succeed
Neither of the above actions will succeed

Q.13.

How can you find rows that do not match some specified condition?

EXISTS
Double use of NOT EXISTS
NOT EXISTS
None of the above is correct

Q.14.

A regular subquery can be processed:

from the top down.
from the bottom up.
by nesting.
None of the above is correct.

Q.15.

What SQL command can be used to add columns to a table?

MODIFY TABLE TableName ADD COLUMN ColumnName
MODIFY TABLE TableName ADD ColumnName
ALTER TABLE TableName ADD COLUMN ColumnName
ALTER TABLE TableName ADD ColumnName

Q.16.

What SQL command will allow you to change the table STUDENT to add the constraint named GradeCheck that states that the values of the Grade column must be greater than 0?

ALTER TABLE STUDENT ALTER CONSTRAINT GradeCheck (Grade > 0);
ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck (Grade > 0);
ALTER TABLE STUDENT ADD CONSTRAINT GradeCheck CHECK (Grade > 0);
None of the above is correct.

Q.17.

The EXISTS keyword will be true if:

any row in the subquery meets the condition only.
all rows in the subquery fail the condition only.
both of these two conditions are met.
neither of these two conditions is met.

Q.18.

Before any changes to database structure are attempted one should first:

clearly understand the current structure and contents of the database only.
test any changes on a test database only.
create a complete backup of the operational database only.
All of the above should be done.

Q.19.

Which of the following SQL statements are helpful in database redesign?

Correlated subqueries only
EXISTS/NOT EXISTS expressions only
Both of the above are helpful
None of the above are helpful.

Q.20.

Which is not true of a correlated subquery?

EXISTS/NOT EXISTS is a form of a correlated subquery.
The processing of the SELECT statements is nested.
They can be used to verify functional dependencies.
They are very similar to a regular subquery.

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