Database Normal Forms Quiz
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Questions and Answers

Which of the following accurately describes the Reflexivity Rule?

  • If 𝑋 → 𝑌 holds, then 𝑆 → 𝑌 also holds for any set 𝑆.
  • If dependency 𝑋 → 𝑌 holds, then 𝑌 → 𝑋 also holds.
  • If attributes A and B exist, then A and B together can imply A and B.
  • If 𝑌 is a subset of 𝑋, then 𝑋 → 𝑌 holds. (correct)

What does the Augmentation Rule state?

  • If 𝑌 is a subset of 𝑆, then 𝑋𝑌 → 𝑆 holds.
  • If 𝑋 → 𝑌 holds, then 𝑌 → 𝑆 also holds for any set 𝑆.
  • If 𝑋 → 𝑌 holds, then 𝑋 → 𝑌𝐶 also holds for any attribute set 𝐶. (correct)
  • If 𝐵 → 𝐶 holds, then 𝐵𝐶 → 𝐷 also holds for any attributes 𝐷.

Which statement accurately reflects the Transitivity Rule?

  • If 𝑋 → 𝑌 holds, then any attribute can be added to both sides.
  • If 𝑋 → 𝑌 and 𝑌 → 𝑍, then 𝑍 → 𝑋 holds.
  • If 𝑌 → 𝑍 holds, then 𝑋 can be ignored in the dependency.
  • If 𝑋 → 𝑌 and 𝑌 → 𝑍, then 𝑋 → 𝑍 holds. (correct)

What implication does the Decomposition Rule have on functional dependencies?

<p>If 𝐴 → 𝐵, 𝐶 holds, then it can be derived that 𝐴 → 𝐵 holds. (C)</p> Signup and view all the answers

In the context of Armstrong's Axioms, which of the following is not a characteristic of inference rules?

<p>Inference rules are based on empirical observations. (A)</p> Signup and view all the answers

Which product has the highest cost among the listed items?

<p>Bat-R (B)</p> Signup and view all the answers

How many unique customers are listed in the provided data?

<p>3 (D)</p> Signup and view all the answers

What is the total quantity of Basketball-SP products ordered by customer ID bsmith1?

<p>3 (D)</p> Signup and view all the answers

Which product has been manufactured by Rawlings?

<p>Softball-R (C)</p> Signup and view all the answers

What is the expected total from the two orders of bsmith2?

<p>$88 (C)</p> Signup and view all the answers

What is the quantity of Softball-R ordered by customer ID jthomas1?

<p>2 (D)</p> Signup and view all the answers

What constitutes a violation of Boyce Codd Normal Form (BCNF)?

<p>Having non-key dependencies for non-key attributes (B)</p> Signup and view all the answers

Which order corresponds to the date 8/10/2018?

<p>Order ID 2 (B)</p> Signup and view all the answers

What is the product ID for the Basketball manufactured by Spaulding?

<p>Basketball-SP (C)</p> Signup and view all the answers

Which statement is true regarding Third Normal Form (3NF)?

<p>There should be no non-key dependencies for non-key attributes. (A)</p> Signup and view all the answers

Which customer has the email address [email protected]?

<p>Bob Smith from 5 Maple Street (B)</p> Signup and view all the answers

Which of the following is a requirement for a table to be considered in Second Normal Form (2NF)?

<p>There should be no partial dependencies (D)</p> Signup and view all the answers

What is the primary focus of the Fourth Normal Form (4NF)?

<p>Avoiding multivalued dependencies (A)</p> Signup and view all the answers

What is the specified product detail for Bat-L?

<p>33 Inch (A)</p> Signup and view all the answers

In database normalization, which of the following defines a non-key dependency?

<p>A relationship where an attribute is dependent on another non-key attribute (D)</p> Signup and view all the answers

Which of the following best describes the term 'functional dependency' in the context of database design?

<p>It indicates the relationship between attributes where one attribute determines another. (A)</p> Signup and view all the answers

Which of these conditions must be true for a table to be classified as in First Normal Form (1NF)?

<p>It must only contain atomic values and have no duplicates. (A)</p> Signup and view all the answers

In the context of normalization, what does the statement 'Nothing but the Key' signify?

<p>Attributes depend only on the primary key and not on other non-key attributes. (B)</p> Signup and view all the answers

Which normal form eliminates transitive dependencies from a database?

<p>Third Normal Form (3NF) (D)</p> Signup and view all the answers

What is a critical aspect of relational schema design according to the normalization process?

<p>Disallow the possibility of spurious tuples (A)</p> Signup and view all the answers

Which of the following accurately describes functional dependency?

<p>It suggests that if two tuples agree on X, they must agree on Y. (B)</p> Signup and view all the answers

Which condition must be satisfied for a table to be in First Normal Form (1NF)?

<p>Every cell must contain atomic values and no duplicates. (C)</p> Signup and view all the answers

What is the main goal of normalization in database design?

<p>To organize tables and reduce redundancy (D)</p> Signup and view all the answers

Which of the following statements is true concerning the Second Normal Form (2NF)?

<p>A table in 2NF must first be in First Normal Form (1NF). (C)</p> Signup and view all the answers

Which of the following best describes anomalies that normalization aims to avoid?

<p>Data duplication causing unnecessary complexity (B)</p> Signup and view all the answers

What is an essential requirement for a relation to be in Boyce-Codd Normal Form (BCNF)?

<p>Every non-trivial functional dependency must have a superkey as its determinant. (B)</p> Signup and view all the answers

What is a partial functional dependency?

<p>A dependency where the entire left side of a functional dependency is not necessary to determine the right side. (A)</p> Signup and view all the answers

Which type of functional dependency is not allowed in 2NF?

<p>Partial functional dependency (B)</p> Signup and view all the answers

What characterizes a transitive functional dependency?

<p>A dependency where an attribute is dependent on another through multiple levels. (A)</p> Signup and view all the answers

What is the primary reason for enforcing Fourth Normal Form (4NF)?

<p>To prevent redundancy caused by multivalued dependencies. (C)</p> Signup and view all the answers

Which of the following is a consequence of a 1NF violation?

<p>Attributes containing non-atomic values or lists. (D)</p> Signup and view all the answers

How does one identify a multivalued functional dependency?

<p>By ensuring that one attribute functionally determines multiple values of another independent attribute. (D)</p> Signup and view all the answers

In a database with a transitive dependency, which of the following must be true?

<p>One non-key attribute must directly depend on another non-key attribute. (A)</p> Signup and view all the answers

What does full functional dependency guarantee?

<p>All attributes on the left side are necessary to determine those on the right side. (D)</p> Signup and view all the answers

Flashcards

Normalization

A database design technique that aims to reduce data redundancy, avoid anomalies, and ensure data dependency. It uses functional dependencies to organize tables and achieve higher normal forms.

Functional Dependency (FD)

A constraint between attribute sets, where the values of one set functionally determine the values of another set. This means if two tuples have the same value for the first set, they must also have the same value for the second set.

Second Normal Form (2NF)

A normal form where every attribute in a relation depends on the entire primary key. This prevents unnecessary duplication of data and ensures data integrity.

Third Normal Form (3NF)

A normal form where the table is in 2NF and every non-prime attribute is fully dependent on the primary key. This prevents redundancy and ensures no attribute is dependent on just a part of the primary key.

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Boyce-Codd Normal Form (BCNF)

A normal form where the table is in 3NF and does not have any multi-valued dependencies. This helps to avoid unnecessary duplication and ensures data consistency.

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Fourth Normal Form (4NF)

A normal form where the table is in BCNF and contains no transitive dependencies. This ensures that every data dependency is direct and avoids any redundant information.

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First Normal Form (1NF)

A normal form where each cell of a table contains atomic values. This means that there should be no repeating groups of values and each value represents a single piece of data.

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1NF

A table is in 1NF if all attributes are atomic and there are no repeating groups.

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2NF

A table is in 2NF if it is in 1NF and all non-key attributes are fully functionally dependent on the primary key. No partial dependencies.

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3NF

A table is in 3NF if it is in 2NF and there are no transitive dependencies. This means that non-key attributes are not dependent on other non-key attributes.

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BCNF

A table is in BCNF (Boyce-Codd Normal Form) if it is in 3NF and all determinants are candidate keys. This means no non-key attributes can determine other non-key attributes.

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4NF

A table is in 4NF if it is in BCNF and there are no multivalued dependencies. This means that there are no independent multivalued facts about an entity.

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Functional Dependency

A functional dependency (FD) is a relationship between attributes where the value of one attribute determines the value of another attribute.

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Partial Dependency

A partial dependency occurs when a non-key attribute depends on only a part of the primary key, not the whole key.

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Transitive Dependency

A transitive dependency occurs when a non-key attribute depends on another non-key attribute, rather than directly on the primary key.

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Multivalued Dependency

A multivalued dependency occurs when an attribute can have multiple values for a given entity, independent of the values of other attributes.

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Partial Functional Dependency

When removing any attribute from the left side of the dependency causes the dependency to no longer hold.

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Transitive Functional Dependency

When an attribute depends on another non-key attribute, which in turn depends on the primary key.

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Multivalued Functional Dependency

When a table has multiple independent, multivalued attributes.

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Fifth Normal Form (5NF)

A table that is in 4NF and has no join dependencies.

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Transitivity Rule

A rule that allows deriving new FDs from existing ones. It states that if attribute set X determines Y, and Y determines Z, then X also determines Z.

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Augmentation Rule

A rule allowing adding attributes to both sides of an existing FD without affecting the dependency. If X determines Y, then adding attributes to both sides (XC and YC) will still maintain the dependency.

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Reflexivity Rule

A rule stating that any subset of an attribute set A also determines A. This ensures that attributes within a set automatically depend on the entire set.

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Armstrong's Axioms

A set of rules used to infer new FDs from existing ones in a relational database. These rules are essential for understanding and managing data dependencies.

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Study Notes

Normal Forms

  • Normal forms are database design techniques for organizing tables, reducing redundancy, and avoiding anomalies.
  • The hierarchy of normal forms, from lowest to highest, includes 1NF, 2NF, 3NF, BCNF, and 4NF.
  • 1NF: Each cell in a table contains atomic values, and there are no duplicate values. All tuple values in an attribute must be from the same domain.
  • 2NF: A table must be in 1NF. Every non-key attribute is fully functionally dependent on the primary key.
  • 3NF: A table must be in 2NF. Non-key attributes must not depend on other non-key attributes (no transitive dependency).
  • BCNF: A table must be in 3NF. Every determinant is a candidate key.
  • 4NF: A table must be in BCNF. No multivalued dependencies exist.

Guidelines

  • Guidelines for good relation schema design: Attributes' semantics should be clear, information redundancy should be minimized, null values should be reduced, spurious tuples should be avoided.

Functional Dependency

  • Functional dependency (FD): A constraint between two sets of attributes, where the values of one set (determinant) determine the values of another set (dependent).
  • X functionally determines Y (X → Y), if every two tuples that have the same X value also have the same Y value.

Normalization

  • A database design technique that organizes tables to reduce redundancy and avoid anomalies. It uses functional dependencies.
  • Relations are improved by being in high order normal forms.

First Normal Form (1NF)

  • Each table cell must contain a single, atomic value.
  • No repeating groups (duplicate values) in a column.
  • All columns must have the same domain (type of data).

Second Normal Form (2NF)

  • Must be in 1NF.
  • Each non-key attribute must be fully functionally dependent on the entire primary key.

Third Normal Form (3NF)

  • Must be in 2NF.
  • Non-key attributes must not depend on other non-key attributes. (No transitive dependency)

Boyce-Codd Normal Form (BCNF)

  • Must be in 3NF.
  • All determinants must be candidate keys.

Fourth Normal Form (4NF)

  • Must be in BCNF.
  • No multivalued dependencies.

Armstrong's Axioms

  • Used to infer functional dependencies in relational databases.
  • Fundamental inference rules that are used to prove whether new dependencies can be inferred from the ones we already have.
  • Include Reflexivity, Augmentation, Transitivity, Decomposition, and Union rules.

Closure

  • The closure of a set of functional dependencies (FDs) is the set of all implied FDs.

Primary Keys

  • Unique keys that identify unique records in a table (a natural functional dependency).

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Description

Test your knowledge on the various normal forms in database design, including 1NF, 2NF, 3NF, BCNF, and 4NF. This quiz will also cover guidelines for effective relational schema design and functional dependencies.

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