chapter 7 Storing Organizational Information - Databases

Information is stored in databases

–Database – maintains information about various types of objects (inventory), events (transactions), people (employees), and places (warehouses)

Database models include:

–Hierarchical database model – information is organized into a tree-like structure (using parent/child relationships) in such a way that it cannot have too many relationships

–Network database model – a flexible way of representing objects and their relationships

–Relational database model – stores information in the form of logically related two-dimensional tables

 Entities and Attributes

Entity – a person, place, thing, transaction, or event about which information is stored

–The rows in each table contain the entities

–In Figure 7.1 CUSTOMER includes Dave’s Sub Shop and Pizza Palace entities

Attributes (fields, columns) – characteristics or properties of an entity class

–The columns in each table contain the attributes

–In Figure 7.1 attributes for CUSTOMER include Customer ID, Customer Name, Contact Name