Database Concepts and Data Modeling in Information Systems

Physical Data Model

A technical description of how information will actually be stored in a specific system.

Data Lake

A very large storage location that holds raw facts from many sources without requiring them to be structured first.

Database

An organized collection of related facts stored electronically so they can be accessed and managed easily.

Entity Instance

One specific example of something in that category.

Constraint

A rule that controls what values are allowed so stored facts remain accurate and consistent.

Cardinality Constraint

A rule that defines how many items from one category can connect to another.

Systems Development Life Cycle (SDLC)

A step‑by‑step process used to design, build, test, and maintain information systems.

Associative Entity

A structure used to connect two categories and store information about their relationship.

Entity Type

A category of similar objects that share common characteristics.

Strong Entity Type

A category that can exist independently without relying on another one.

Weak Entity

A category that cannot exist without depending on another one for identification.

Multivalued Attribute

A characteristic that can contain more than one value for the same item.

Attribute

A characteristic used to describe something in the system.

Identifying Relationship

A connection that links a dependent category to the one it relies on.

Entity

A person, place, object, event, or idea that an organization wants to store information about.

Logical Data Model

A design that shows how information will be structured using tables, columns, keys, and relationships.

Conceptual Data Model

A detailed description of what information an organization needs and how the pieces relate to each other.

Prototyping

A development approach where an early working version of a system is built and repeatedly improved using feedback.

Enterprise Data Model

A high‑level view showing the main types of information used across an organization.

Data Warehouse

A large storage system that collects information from many systems so organizations can analyze it and make decisions.

Enterprise Resource Planning (ERP)

A large system that connects many departments of a company so they can share and manage information together.

Relationship Type

A meaningful connection between two or more categories of objects.

Metadata

Details that explain and describe other stored facts, such as what a column means or what values it stores.

Information

Facts that have been organized or processed so they become meaningful and useful.

Data

Individual facts about people, objects, or events stored in a computer system.

Database Management System (DBMS)

Software used to create, store, organize, and control access to collections of stored facts.