Question 1

There is no known general algorithm to convert tables to DKNF.

Accepted Answer

DKNF (Domain/ Key Normal Form) is the highest level of normalization in database design. It ensures that every constraint on the table can be enforced by defining a constraint on a single table. It is not always possible to convert a table directly to DKNF, and there is no known general algorithm to achieve this. The process of normalization involves multiple steps, and the designer needs to consider various factors like domains, keys, dependencies, and functional dependencies, to achieve the desired level of normalization.

Question 2

A good database design ensures that users can change the contents of a database without unexpected side effects.

Accepted Answer

A good database design includes the use of data normalization techniques to avoid redundant data and maintain data consistency. It also involves setting up proper constraints, such as foreign key relationships and unique constraints, to prevent unwanted data modifications that could cause unexpected side effects. Therefore, a well-designed database should allow users to change various aspects of the data without affecting other aspects in unintended ways.

Question 3

When you split one table into two smaller tables to achieve 2NF,you can no longer derive the functional dependencies of the original table.

Accepted Answer

Splitting a table into two smaller tables to achieve 2NF does not eliminate the ability to derive the functional dependencies of the original table; it organizes the data to remove partial dependencies on a composite primary key.

Question 4

One of the situations that BCNF addresses which 3NF does not is where part of a key determines part of a key.

Accepted Answer

BCNF addresses situations where a functional dependency exists where part of a candidate key determines another part of a candidate key, which is not addressed by 3NF.

Question 5

If an analysis of relationship independence reveals that redundancies exist,the way to alleviate this situation is to replace the entity with two binary relationships which will each be converted to a table.

Accepted Answer

If redundancies exist in relationship independence, it is best to replace the entity with two binary relationships, each of which can be converted to a table. This helps to reduce redundancy and improve the overall structure of the database.

Question 6

Although 3NF and BCNF usually produce the same table results,3NF is a stronger and simpler definition than BCNF.

Accepted Answer

BCNF (Boyce-Codd Normal Form) is actually a stronger version of 3NF (Third Normal Form). While both aim to reduce redundancy in database tables, BCNF addresses certain types of dependency anomalies that 3NF does not.

Question 7

Primary key and foreign key constraints are both important kinds of value-based constraints.

Accepted Answer

Primary key constraints ensure uniqueness and not null values in a column or a set of columns, while foreign key constraints establish a relationship between columns in different tables, ensuring referential integrity, not value-based constraints.

Question 8

Redundancies can cause insert,update,and delete operations to produce unexpected side effects known as conversion errors.

Accepted Answer

Redundancies can cause insert, update, and delete operations to produce unexpected side effects known as anomalies, not conversion errors. Conversion errors are related to incorrect data type conversions.

Question 9

An unexpected side effect that occurs when changing the data in a table with excessive redundancies is referred to as a Modification Anomaly.

Accepted Answer

Modification anomalies occur when data redundancies are present in a table, and can cause unexpected side effects when data is updated, inserted, or deleted.

Question 10

Due to the extra joins involved,splitting a table because it has multiple candidate keys can degrade query performance.

Accepted Answer

When a table is split due to having multiple candidate keys, additional joins are required to retrieve data from the separate tables. This can result in slower query performance.

Question 11

When part of a key determines a non-key,this is a violation of BCNF.

Accepted Answer

The answer of When part of a key determines a...

Question 12

Although rare,a table in DKNF can still have some modification anomalies.

Accepted Answer

Domain/Key Normal Form (DKNF) is a normalization level designed to handle all possible modification anomalies by ensuring that every constraint on the table is a logical consequence of the table's key and domain constraints. Therefore, a table in DKNF should not have any modification anomalies.

Question 13

In the MVD expressed as $$A \rightarrow \rightarrow B \mid C$$ ,a given A value is associated with one or more B and C values.

Accepted Answer

In a multivalued dependency (MVD) expressed as $A \rightarrow \rightarrow B \mid C$, it means for a given value of A, there can be multiple values of B and C associated with it, independently of each other.

Question 14

To achieve 4NF,it is possible that there may be M-way relationships that should be split into two or more binary relationships to avoid redundancy.

Accepted Answer

Yes, this statement is true. In 4NF, it is important to avoid multi-valued dependencies among non-key attributes in a relation. If there are M-way relationships (where M is greater than 2) that create such dependencies, it may be necessary to split them into two or more binary relationships to eliminate redundancy and achieve higher normalization.

Question 15

The goal of 2NF and 3NF is to produce tables in which every key determines the other columns.

Accepted Answer

This statement is true. Second Normal Form (2NF) and Third Normal Form (3NF) are aimed at eliminating data redundancy and ensuring that every column in a table depends only on the primary key or keys, and not on any other non-key columns. This means that every key fully determines all other columns in the table.

Question 16

Examining sample data in a table can be used to prove that a functional dependency exists,but it is of no use in proving that a functional dependency does not exist.

Accepted Answer

Examining sample data can help identify potential functional dependencies, but it cannot definitively prove or disprove them, as the sample may not represent all possible data scenarios.

Question 17

Storing a relationship in a database that could otherwise be derived from two independent relationships through a join operation can cause data modification operations to perform slower,but has no effect on modification anomalies.

Accepted Answer

Storing such a relationship can indeed cause data modification anomalies, as it introduces redundancy, which can lead to inconsistencies during updates, inserts, or deletes if not carefully managed.

Question 18

4NF prohibits redundancies caused by MVDs.

Accepted Answer

4NF (Fourth Normal Form) is designed to eliminate multi-valued dependencies (MVDs) that cause redundancies. It ensures that a table contains no independent sets of multi-valued dependencies.

Question 19

Like 4NF,5NF also applies to M-way relationships.

Accepted Answer

5NF applies to M-way relationships. In fact, it is also known as Project-Join Normal Form (PJNF) or Higher Normal Form (HNF), and it deals with reducing data redundancy and dependency in complex M-way relationships.

Question 20

A table with multiple candidate keys violates 3NF and BCNF.

Accepted Answer

Having multiple candidate keys does not violate the Third Normal Form (3NF) or the Boyce-Codd Normal Form (BCNF). These normal forms are concerned with the elimination of redundant data and dependencies that are not related to candidate keys.

Quiz 7: Normalization of Relational Tables

There is no known general algorithm to convert tables to DKNF.

A good database design ensures that users can change the contents of a database without unexpected side effects.

When you split one table into two smaller tables to achieve 2NF,you can no longer derive the functional dependencies of the original table.

One of the situations that BCNF addresses which 3NF does not is where part of a key determines part of a key.

If an analysis of relationship independence reveals that redundancies exist,the way to alleviate this situation is to replace the entity with two binary relationships which will each be converted to a table.

Although 3NF and BCNF usually produce the same table results,3NF is a stronger and simpler definition than BCNF.

Primary key and foreign key constraints are both important kinds of value-based constraints.

Redundancies can cause insert,update,and delete operations to produce unexpected side effects known as conversion errors.

An unexpected side effect that occurs when changing the data in a table with excessive redundancies is referred to as a Modification Anomaly.

Due to the extra joins involved,splitting a table because it has multiple candidate keys can degrade query performance.

When part of a key determines a non-key,this is a violation of BCNF.

Although rare,a table in DKNF can still have some modification anomalies.

In the MVD expressed as $A \rightarrow \rightarrow B \mid C$ ,a given A value is associated with one or more B and C values.

To achieve 4NF,it is possible that there may be M-way relationships that should be split into two or more binary relationships to avoid redundancy.

The goal of 2NF and 3NF is to produce tables in which every key determines the other columns.

Examining sample data in a table can be used to prove that a functional dependency exists,but it is of no use in proving that a functional dependency does not exist.

Storing a relationship in a database that could otherwise be derived from two independent relationships through a join operation can cause data modification operations to perform slower,but has no effect on modification anomalies.

4NF prohibits redundancies caused by MVDs.

Like 4NF,5NF also applies to M-way relationships.

A table with multiple candidate keys violates 3NF and BCNF.

Quiz 7: Normalization of Relational Tables

There is no known general algorithm to convert tables to DKNF.

A good database design ensures that users can change the contents of a database without unexpected side effects.

When you split one table into two smaller tables to achieve 2NF,you can no longer derive the functional dependencies of the original table.

One of the situations that BCNF addresses which 3NF does not is where part of a key determines part of a key.

If an analysis of relationship independence reveals that redundancies exist,the way to alleviate this situation is to replace the entity with two binary relationships which will each be converted to a table.

Although 3NF and BCNF usually produce the same table results,3NF is a stronger and simpler definition than BCNF.

Primary key and foreign key constraints are both important kinds of value-based constraints.

Redundancies can cause insert,update,and delete operations to produce unexpected side effects known as conversion errors.

An unexpected side effect that occurs when changing the data in a table with excessive redundancies is referred to as a Modification Anomaly.

Due to the extra joins involved,splitting a table because it has multiple candidate keys can degrade query performance.

When part of a key determines a non-key,this is a violation of BCNF.

Although rare,a table in DKNF can still have some modification anomalies.

In the MVD expressed as A→→B∣CA \rightarrow \rightarrow B \mid CA→→B∣C ,a given A value is associated with one or more B and C values.

To achieve 4NF,it is possible that there may be M-way relationships that should be split into two or more binary relationships to avoid redundancy.

The goal of 2NF and 3NF is to produce tables in which every key determines the other columns.

Examining sample data in a table can be used to prove that a functional dependency exists,but it is of no use in proving that a functional dependency does not exist.

Storing a relationship in a database that could otherwise be derived from two independent relationships through a join operation can cause data modification operations to perform slower,but has no effect on modification anomalies.

4NF prohibits redundancies caused by MVDs.

Like 4NF,5NF also applies to M-way relationships.

A table with multiple candidate keys violates 3NF and BCNF.

In the MVD expressed as $A \rightarrow \rightarrow B \mid C$ ,a given A value is associated with one or more B and C values.