Database Normalization Terminology

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Questions and Answers

What is a key characteristic of a candidate key?

It can be a combination of any columns.

It can contain extra columns for identification.

It is a specific type of super key that is minimal. (correct)

It must include at least two columns.

When is a composite key used in a database?

When a single column can uniquely identify records.

When two or more columns together are needed for unique identification. (correct)

When a key must be minimal.

When a table can stand alone without relations.

What does a database schema represent?

A method for indexing data in the database.

The rules enforced on data updates.

A detailed plan showing how data is organized and connected. (correct)

The physical storage of the database files.

What is the purpose of normalization in data management?

To ensure each piece of information is stored only once. Signup and view all the answers

What issue can arise from having repeating groups in a database table?

It can cause data inconsistencies and complicate management. Signup and view all the answers

Which of the following accurately describes a database?

An organized collection of data stored electronically. Signup and view all the answers

Which of the following describes data redundancy?

Storing the same information in more than one location. Signup and view all the answers

In the context of database normalization, what does it mean to convert repeating groups?

To create new tables to separate similar data types. Signup and view all the answers

How are fields in a database table defined?

Synonymous with columns in the table. Signup and view all the answers

What defines a primary key in a database table?

A unique identifier for each record. Signup and view all the answers

Which statement is true regarding an entity in a database?

An entity is equivalent to a table. Signup and view all the answers

Which statement about a relation in relational databases is true?

Relations do not have a specific order. Signup and view all the answers

What is the role of a property in a database?

To define the basic elements of an entity. Signup and view all the answers

What does a super key consist of?

A combination of fields that can identify a record uniquely. Signup and view all the answers

Which of the following is NOT a characteristic of a primary key?

It can include null values. Signup and view all the answers

In the context of a student database, which of the following could serve as a primary key?

Student ID Signup and view all the answers

What is transitive dependency in database design?

Dependency of one piece of data on another through a third piece. Signup and view all the answers

Which of the following best describes derived data?

Data created by calculations from existing data rather than being stored directly. Signup and view all the answers

What does an update anomaly lead to in a database?

Inconsistent data across multiple records Signup and view all the answers

In which scenario would an insert anomaly likely occur?

Adding a new department with no assigned teacher Signup and view all the answers

What issue can duplicate data cause in a database?

Complications in data management and retrieval. Signup and view all the answers

What is atomic data in the context of database normalisation?

Data that must be stored as a single, indivisible value. Signup and view all the answers

What is the primary cause of a delete anomaly?

Overlapping data requirements in a table Signup and view all the answers

What does referential integrity ensure in database design?

The accuracy and consistency of data across different tables. Signup and view all the answers

How can update anomalies negatively impact data management?

They allow multiple versions of the same information Signup and view all the answers

Why is normalisation important in database management?

It helps to minimise data redundancy and maintain data integrity. Signup and view all the answers

Which best describes an insert anomaly?

Preventing a new entry due to missing related data Signup and view all the answers

What typically triggers a delete anomaly in a database?

Lack of structured tables for related data Signup and view all the answers

Which situation exemplifies transitive dependency?

A student's major is tied to their advisor's department. Signup and view all the answers

What might be a consequence of failing to address update anomalies?

Increased risk of data entry errors Signup and view all the answers

Which of the following is NOT a consequence of having duplicate data?

Higher accuracy in reporting. Signup and view all the answers

What issue can arise when addresses of students are not properly updated?

Potential confusion with conflicting addresses Signup and view all the answers

What is one consequence of deleting a club that has no members left?

You also delete all details of students who were part of that club. Signup and view all the answers

Which of the following is NOT a requirement of the First Normal Form (1NF)?

All columns must be numeric. Signup and view all the answers

To be in Second Normal Form (2NF), a table must first be in which form?

First Normal Form Signup and view all the answers

What does the term 'partial dependency' refer to in database normalization?

A non-key attribute depends on only a part of a composite primary key. Signup and view all the answers

In Third Normal Form (3NF), what type of dependencies must be avoided?

Transitive dependencies Signup and view all the answers

Which statement is true about unique column names in a database table?

All columns must have unique names to avoid confusion. Signup and view all the answers

Which condition must be met for a table to be classified as being in 2NF?

All non-key attributes depend on the entire primary key. Signup and view all the answers

What is the main goal of normalization in database design?

To minimize redundancy and dependency issues. Signup and view all the answers

Study Notes

Normalization Terminology

Normalization is a process that organizes data to store each piece of information only once, improving data management and accuracy.
A database is an organized collection of data allowing for efficient access, management, and updates.
A table is a structured collection of related data in rows and columns.
A record is a single entry in a table, represented by a row.
Fields (or columns) are the attributes or properties stored in a table (e.g., student ID, name, age).
A relation, in the context of relational databases, is a table. While synonymous, relation is a mathematical term while table is a database term.
A primary key is a special column that uniquely identifies each record in a table to prevent duplicate records.
A primary key cannot have empty values.
A super key is a set of one or more columns that can uniquely identify a record in a table.
A candidate key is a minimal super key; removing any column will prevent unique identification.
Composite key is a primary key made up of two or more columns.
Entity instance is a single record in a table (row).
Entity is a table containing records of the same type (e.g., students, courses).
Property refers to fields representing characteristics of entities.
Database schema is a blueprint of the database, outlining table structures, fields, and relationships.
Repeating groups are multiple similar fields for the same piece of information in one record.
Data redundancy is storing the same information in multiple places, leading to space waste and update/insert/deletion anomalies.

Further Normalization Concepts

Update anomaly: Changing information in one place, but not all, creates inconsistencies.
Insert anomaly: Preventing the addition of new information due to incomplete data.
Delete anomaly: Deleting one record unintentionally deletes other crucial information relating to that record.
1st Normal Form (1NF): Each cell in a table must have only one value and there are no repeating groups.
Atomic values: Each cell can contain only one value.
No repeating groups: Each piece of information should be stored in its own column.
Unique column names: Each column should have a distinct name.
Unique identifier (primary key): Each row needs a unique identifier.
2nd Normal Form (2NF): Must be in 1NF and all non-key attributes must depend on the entire primary key.
3rd Normal Form (3NF): Must be in 2NF and there are no transitive dependencies.
Partial dependency: In 2NF, non-key attributes should depend entirely on the primary key.
Transitive dependency: Non-key attributes should not depend on other non-key attributes.
Derived data: Data calculated based on other information.
Duplicate data: The same information stored multiple times.
Referential integrity: Maintaining consistency and ensuring data relationships aren't broken by foreign key constraints.

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Description

This quiz covers essential terminology related to normalization in databases, assisting in understanding how data is organized for better management and accuracy. Topics include definitions of tables, records, fields, and keys, providing a foundation for relational database concepts.