REA Ontology

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REA Ontology

• Resource - Event - Agent

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Example of Exchange 1
Subscriber
Publisher
Magazine
Subscription
Payment
Delivery
3
Example of Exchange 2
Customer
Company
Product
Order
Payment
Shipment
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Example of Exchange 3
Customer
Company
Product
Order
Order line
Payment
Shipment
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REA - Intuition
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Economic Resource

• An economic resource is something of value that
  is under the control of an enterprise and that
  can be transferred from one agent to another
• Examples cash, inventory,labour service

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Economic Event

• An economic event is the transfer of control of
  an economic resource from one agent to another
  agent
• Examples sale, cash-payment, shipment

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Economic Agent

• An economic agent is someone who is able to
  participate in economic events
• Examples manufacturer, distributor, carrier, end
  customer

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Duality
Customer
Company
Product
Order
Order line
Events
Payment
Shipment
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Duality

• Duality is a relationship between economic events
  expressing that in order to obtain an economic
  resource, an agent must give up another economic
  resource
• One good turn deserves another

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Basic REA Pattern
custody
Economic Resource
Economic Event
Economic Agent
duality
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Basic REA Pattern
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Commitments and Contracts
Customer
Company
Product
Order
Order line
Events
Payment
Shipment
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Commitment

• An obligation to perform an economic event in the
  future
• Example order lines

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Contract

• A contract is a container for a collection of
  commitments
• Example purchase order with several line items

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UMM Business Requirements View (simplified)
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Operational Level and Knowledge Level
Knowledge Level
Operational Level
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Operational Level and Knowledge Level
Knowledge Level
Operational Level
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REA Enterprise Modeling
custody
linkage
association
reserves stock-flow
Economic Commitment/Event Type
Economic Resource Type
Economic Agent Type
Economic Commitment/Event Type
participation
dual executes reciprocal
Knowledge level
typification
Operational level
Commitment
Commitment
reciprocal
participation
reserves
executes
executes
Economic Event
Economic Resource
Economic Event
Economic Agent
dual
stock-flow
participation
custody
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Utilising the REA patterns

• What economic agents are there?
• What economic resources are there? Which agents
  control them?
• What economic events are there?
• Which economic events are dual?
• What commitments are made?
• What contracts are made?
• What is needed on the knowledge level?

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Exercise

• A catering company has a number of offices
  around the country that offer meal services to
  its customers. The customers can choose from a
  wide variety of dishes. A customer orders one
  meal that may consist of several dishes. The
  dishes are procured from suppliers.
• Some information requirements are
• Which customers have not paid for all the
  deliveries they have got?
• Which customers have ordered a meal that has not
  yet been delivered?
• Which customers have ordered meals containing a
  dish from supplier XXX?
• Which is the most popular dish?
• Which suppliers can deliver YYY dishes?

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Process Overview

• For each exchange (pair of economic events),
  introduce a process
• Look at each process from one agents perspective
  (typically the organisation for which the model
  is constructed)
• For each process, specify what resources are
  increased and decreased
• Connect the processes according to resources
  consumed and produced

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Process Overview - Example
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Dish supplier
Dish order
Dish delivery
Dish payment
Dish order line
Dish
Dish type
Meal
Meal type
Office
Meal order
Meal delivery
Meal payment
Customer