What is an ERD. Define the ERD related terms, including entities, attributes, cardinalities, and relationship.

 Entity Relationship Diagram.

What is an ER diagram?

An Entity Relationship (ER) Diagram is a type of flowchart that illustrates how “entities” such as people, objects or concepts relate to each other within a system. ER Diagrams are most often used to design or debug relational databases in the fields of software engineering, business information systems, education, and research. Also known as ERDs or ER Models, they use a defined set of symbols such as rectangles, diamonds, ovals and connecting lines to depict the interconnectedness of entities, relationships and their attributes. They mirror grammatical structure, with entities as nouns and relationships as verbs. (Lucidchart, 2023)

(Lucidchart, 2023)

Entity

A single unique object in the real world that is being mastered. Examples of an entity are a single person, a single product, or a single organization.

 Entity type

A person, organization, object type, or concept about which information is stored. Describes the type of information that is being mastered. An entity type typically corresponds to one or several related tables in a database.

Attribute

A characteristic or trait of an entity type that describes the entity, for example, the Person entity type has the Date of the Birth attribute. (Key Concepts, 2023)

Relationship

It describes how entities related one to another.

Cardinalities

Cardinality is a mathematical term, and it tells us the number of interactions entities have with each other. Cardinality is simply a number ratio expressed in symbols, like one-to-one, one-to-many, and many-to-many. (Gleek, 2023)

Reference List:

Gleek (2023) Diagram maker for developers. Available at: https://www.gleek.io/blog/er-model-cardinality (Accessed: March 16, 2023).

Key concepts (2023) Key concepts: Entity, attribute, and entity type. Available at: https://www.ibm.com/docs/en/imdm/12.0?topic=concepts-key-entity-attribute-entity-type (Accessed: March 16, 2023).

Lucidchart (2023) What is an entity relationship diagram (ERD)?. Available at: https://www.lucidchart.com/pages/er-diagrams (Accessed: March 16, 2023).