Database Redesign Test(1st)

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

1 Mark(s)

database design.
None of the above is correct.
reverse engineering.
data modeling.

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

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All of the above should be done.
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.

The use of the double NOT EXISTS can be used to find rows that do not match some specified condition.

1 Mark(s)

False
True

The NOT EXISTS keyword will be true if:

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

Dependency graphs are diagrams that consist of nodes and arcs that show the dependencies of a database.

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True
False

Because of the need for extensive knowledge of SQL, many database developers choose to automate the redesign process.

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False
True

The EXISTS keyword will be true if any row in the subquery meets the condition.

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True
False

The SQL-92 command to change a table name is RENAME TABLE.

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False
True

The data model that is produced from reverse engineering is:

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

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

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

A regular subquery is processed from the bottom up.

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True
False

Which SQL-92 standard SQL command can be used to change a table name?

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None of the above is correct
CHANGE TABLE
RENAME TABLE
ALTER TABLE

Correlated subqueries are similar to a regular subquery.

1 Mark(s)

True
False

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?

1 Mark(s)

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

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

1 Mark(s)

None of the above is correct
skeptical
optimistic
ambivalent

Which of the following modifications may not succeed?

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

Which is not true of a correlated subquery?

1 Mark(s)

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

If a database is built correctly the first time, it will not have to be redesigned.

1 Mark(s)

False
True

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

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Four
One
Two
Three

What SQL command can be used to delete columns from a table?

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ALTER TABLE TableName DROP ColumnName
MODIFY TABLE TableName DROP COLUMN ColumnName
ALTER TABLE TableName DROP COLUMN ColumnName
MODIFY TABLE TableName DROP ColumnName

Changing cardinalities in a database is:

1 Mark(s)

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.

It is not easy to build a database correctly the first time.

1 Mark(s)

False
True

Database redesign is not terribly difficult if the:

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database is relatively small.
database is well-designed.
database is structured.
database has no data.

A regular subquery can be processed:

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

Reverse engineering is the process of reading a database schema and producing a data model from that schema.

1 Mark(s)

False
True

A correlated subquery is processed as a nested subquery.

1 Mark(s)

True
False

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

1 Mark(s)

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

The EXISTS keyword will be true if:

1 Mark(s)

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

Information systems and organizations do not just influence each other; they create each other.

1 Mark(s)

True
False

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

1 Mark(s)

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

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

1 Mark(s)

False
True

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

1 Mark(s)

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

The NOT EXISTS keyword will be true if any row in the subquery meets the condition.

1 Mark(s)

False
True

Typically, there should be at least two different copies of the database schema used in the redesign process.

1 Mark(s)

True
False

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

1 Mark(s)

False
True

Although creating test databases is a critical and necessary job, there are few career opportunities in this area.

1 Mark(s)

True
False

The data model produced from the reverse engineering process is a true logical model.

1 Mark(s)

False
True

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

1 Mark(s)

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

The data model produced from the reverse engineering process does not include intersection table data.

1 Mark(s)

False
True

Adding null columns to a table is straightforward.

1 Mark(s)

False
True

Database Redesign Test(1st) : Question 1 of 40