Exam2

Entity

An object or thing in the real world that is distinguishable from other objects, represented as a table in a database.

Relationship

The association between two or more entities in a database that defines how they are related.

One-to-many

A relationship type where one instance of the first entity can relate to multiple instances of the second entity.

Many-to-many

A relationship type where multiple instances of one entity can relate to multiple instances of another entity.

ER Modeling

A conceptual framework for designing databases using entities, relationships, and attributes.

ER Diagram

A graphical representation of the entities, relationships, and attributes in an ER model.

Data Redundancy

The unnecessary repetition of data within a database, leading to inconsistencies.

Single-valued

An attribute that can hold only one value per record.

Multi-valued

An attribute that can hold multiple values per record.

Top-down

A design approach that starts with a high-level overview and breaks it down into smaller components.

Bottom-up

A design approach that begins with specific details and works up to the full system.

First Normal Form (1NF)

A database is in 1NF if all columns contain atomic values and there are no repeating groups.

Flattening

The process of converting a multi-dimensional structure into a flat, two-dimensional format.

Data Anomaly

An inconsistency or problem in the database due to poor design.

Insertion Anomaly

A problem occurring when certain data cannot be inserted without other data present.

Deletion Anomaly

An issue that arises when deleting data results in unintended loss of related data.

Update Anomaly

A situation where data duplication requires multiple updates, risking inconsistencies.

Primary Key

A unique identifier for each record in a database table.

Candidate Key

A set of attributes that can uniquely identify each record in a table.

Composite Key

A key composed of two or more attributes that together uniquely identify a record.

Foreign Key

An attribute in a table that refers to the primary key of another table.

Lossless Join Property

A property of decomposition where no information is lost, allowing reconstruction of the original table.

Functional Dependence

A relationship where the value of one attribute determines the value of another.

Determinant

An attribute that uniquely determines the value of another attribute in functional dependency.

Partial Dependence

A type of dependence where an attribute depends on part of a composite primary key.

Second Normal Form (2NF)

A table is in 2NF if it is in 1NF and all non-key attributes depend on the entire primary key.

Transitive Dependence

A functional dependency where one non-key attribute depends on another, violating 3NF.

Third Normal Form (3NF)

A table is in 3NF if it is in 2NF and all attributes are directly dependent on the primary key.

Atomic

Data that cannot be divided into smaller units; holds a single, indivisible value.

Parse

To analyze and break down data or syntax into smaller components for processing.

Decomposition

The process of breaking down a database table to remove redundancy.