The REA Approach to Database
chapter
10
The REA Approach to
Database Modeling
T
his chapter examines the resources, events, and agents (REA) model as a means of specifying and designing accounting information systems that serve the needs of all of the users in an organization. The chapter is comprised of three major sections. The first introduces the
REA approach and comments on the general problems associated with traditional accounting practice that can be resolved through an REA approach. This section presents the
REA model and describes the structure of an REA diagram.
The basic REA model consists of three entity types
(resources, events, and agents) and a set of associations linking them. Resources are things of economic value to the organization and are the objects of economic exchanges with trading partners. REA events fall into two general groups: economic events and support events. Economic events are phenomena that effect changes (increases or decreases) in resources. Support events include control, planning, and management activities that are related to economic events but do not directly effect a change in resources. Agents are individuals within and outside the organization who participate in an economic event. A key feature of REA is the concept of economic duality. Each economic event is mirrored by another event in the opposite direction. These dual events constitute the give event and receive event of an economic exchange.
The second section presents the multistep process of view modeling to create an REA model. The focus here is on modeling a single view of the entire database. The steps involved are: (1) identify the event entities to be modeled,
(2) identify the resource entities changed by events, (3) identify the agent entities participating in events, and (4) determine associations and cardinalities between entities.
The third and final section presents the task of view integration, in which several individual REA diagrams are integrated into a single enterprise-wide
10
The REA Approach to
Database Modeling
T
his chapter examines the resources, events, and agents (REA) model as a means of specifying and designing accounting information systems that serve the needs of all of the users in an organization. The chapter is comprised of three major sections. The first introduces the
REA approach and comments on the general problems associated with traditional accounting practice that can be resolved through an REA approach. This section presents the
REA model and describes the structure of an REA diagram.
The basic REA model consists of three entity types
(resources, events, and agents) and a set of associations linking them. Resources are things of economic value to the organization and are the objects of economic exchanges with trading partners. REA events fall into two general groups: economic events and support events. Economic events are phenomena that effect changes (increases or decreases) in resources. Support events include control, planning, and management activities that are related to economic events but do not directly effect a change in resources. Agents are individuals within and outside the organization who participate in an economic event. A key feature of REA is the concept of economic duality. Each economic event is mirrored by another event in the opposite direction. These dual events constitute the give event and receive event of an economic exchange.
The second section presents the multistep process of view modeling to create an REA model. The focus here is on modeling a single view of the entire database. The steps involved are: (1) identify the event entities to be modeled,
(2) identify the resource entities changed by events, (3) identify the agent entities participating in events, and (4) determine associations and cardinalities between entities.
The third and final section presents the task of view integration, in which several individual REA diagrams are integrated into a single enterprise-wide