Database and Database Management System

Database

A collection of tables (also called relations). A 2-dimensional table with rows and column intersections. Each table represents one type of entity.

Database Management System (DBMS)

Software that manages huge databases. Examples: Access, Oracle, DB2, FoxPro, Sybase (acquired by SAP).

Where does TPS data go?

Data from TPS goes to a database to be stored and processed later by Decision Support Systems (DSS) or other information systems.

Table (Relation)

A 2-dimensional table with a series of row/column intersections. Represents one type of entity (e.g., a table for agents, a separate table for customers).

Attribute (Column / Field)

One characteristic or property of a type of entity (e.g., customer's address, phone number, birth date).

Record (Row / Tuple)

Represents a particular entity (e.g., a specific customer or agent). Has logically connected fields that describe that entity.

Primary Key

An attribute(s) that uniquely identifies each row (entity) in a table. Must be unique and have no null values. Can be a single field or multiple fields (e.g., HKID, car registration number).

Foreign Key

A field whose values must match the primary key in another table. Used to create relationships (1:1, 1:M, or M:M) between tables.

1:M Relationship (One-to-Many)

A relationship where one entity in a table is related to many entities in another table. Example: one agent can be in charge of many customers, but each customer deals with only one agent.

Relational Database Schema

A design showing table structures, relationships between tables, and determination of primary and foreign keys.