Representations and Patterns_ Chapter 2

We can't understand enterprise info systems w/o models that serve as representations of the systems and their underlying reality.

Surrogates for the real contruct (aka, symbol for the contstruct)

may symbolize individual objects or categories of objects.

• Individual objects. Individual instance of something, such as Fred's Little Red Corvette

A token level relationship shows each individual instance in the reality represented as a separate token.

Categories of objects, such as Car. Shape. (vs. token level of red corvette, triangle.)

An arrangement of repeated or recognizably consistent objects or actions.

Patterns allow us to make predictions about future events and to make sense of the present based on our past experiences.

• A common language. A specification of conceptualization. A generally understood means of representing enterprise patterns and scripts.
• Example in class about terminology on tv. medical dramas. Depending on the domain you are in , words take on different meanings.

Basically a simplified view of something. Abstract. Simplified view of the world that we wish to represent for some purpose. Like our sua.

The symbols used to portray the concepts of interest. Means something larger. Nike Swoosh. American Flag.

• A consistent characteristic form, style, or method as a composite of traits or features characteristic of an individual or group. 
• Putting Symbols together creates a pattern
• Scattershot of the symbols. No time/order reference yet.

• A pattern of sequences of events that typically occur in combination
• Scripts put symbols in order, whereas patterns do not impose an order on the symbols.

Purpose of associating like objects with each other. In conceptual modeling, object patterns consist of expected groupings of things and the relationships between them.

Wheras object patterns focus on objects and relationships between them, script patterns are sequences o events that typically occur in combination w/ ea other. 

Context important

• 1.Value System level
• 2. Value Chain level
• 3. Business Process level
• 4. Task level

focuses on the resources that are exchanged between the enterprise and it's various external business partners. Shows the agents and the resources.

INTERNAL. Ripping the roof off. Accounting level, basically.

Focuses on the resource flows between interconnected business processes and on the economic events that accomplish the resource flows.

• Broad term. Can mean anything from a single activity to a transaction cycle. For this chapter we use transaction cycle. Common:
• Financing process
• Acquisition/payment (purch) process
• HR/Payroll process
• Conversion (mfg) process
• Sales/Collection (Revenue) process

• Third level of detail. Focuses more on one or more transaction cycles in an enterprise's value chain. Expands on the Value chain level to include some external elements.
• Shows resources, events, and agents and the relationships among them.

• Focuses on workflow/script.
• individual steps used to accomplish events in an enterprise.

Object pattern (macro level)

• Script pattern. The value chain level models should be created with this overall script in mind but adjusted as appropriate for particular enterprise.:
• *Enterprise gets some money  and engages in value added exchanges
• 1: buy equip and raw mater.
• 2. Purch labor
• 3. Mfg finished goods
• 4. Sell finished goods
• *Enterprise pays back money and takes home profit

No pattern has been identified at task level yet

• Value system - company as whole vs external agents and what resources flow
• Value chain - internal view only. different business processes (like departments) and how they interact w/each other. What resources flow and what are some of the events.
• Business process - Drill down into one department and view the resources, economic events, and agents, relationships (stockflow ec.) Merged and converted to relational database. 
• Task level- Task detail. Workflow. Introduce flowcharting

a combination of script patterns and object patterns that together enable us to model enterprises and to understand and work with existing enterprise models///levels of models slide

• LEVEL
• 3

Drilldown into a function/PROCESS and observe what econmomic exchanges take place

Business process level (object based pattern) snapshot approach

• •A pattern to which the reality of
• most (perhaps all) enterprises conform

• •The key is mapping the objects in
• the enterprise to the pattern in order to generate the model from which a
• database is designed.
• •*****Timing not included here.
• Business process level model is a snapshot. It doesn’t care about the timing,
• just that the interaction exists.
• •This is an REA MODEL. Resources on the left, events
• in the center, agents (internal/external people involved) on the right.

• Task level – basically a
• script/flowchart LEVEL 4

Difference between this and other models is thatthis is the only one that implies a sequence of timing. ****