Database Redesign - General Questions (2)

9.

Changing cardinalities in a database is:

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

Answer: Option A

Explanation:

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10.

The EXISTS keyword will be true if:

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

Answer: Option A

Explanation:

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11.

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

A.	MODIFY TABLE TableName ADD COLUMN ColumnName
B.	MODIFY TABLE TableName ADD ColumnName
C.	ALTER TABLE TableName ADD COLUMN ColumnName
D.	ALTER TABLE TableName ADD ColumnName

Answer: Option D

Explanation:

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12.

A regular subquery can be processed:

A.	from the top down.
B.	from the bottom up.
C.	by nesting.
D.	None of the above is correct.

Answer: Option B

Explanation:

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13.

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

A.	EXISTS
B.	Double use of NOT EXISTS
C.	NOT EXISTS
D.	None of the above is correct.

Answer: Option B

Explanation:

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14.

Which of the following modifications may not succeed?

A.	Changing a column data type from char to date
B.	Changing a column data type from numeric to char
C.	Both of the above actions should succeed.
D.	Neither of the above actions will succeed.

Answer: Option A

Explanation:

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15.

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

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

Answer: Option D

Explanation:

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16.

The process of reading a database schema and producing a data model from that schema is known as:

A.	data modeling.
B.	database design.
C.	reverse engineering.
D.	None of the above is correct.

Answer: Option C

Explanation:

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