4 OVERVIEW ACTIVITY DIAGRAMS The overview activity diagram presents a high level view of the business process by documenting the key events, the sequence of these events, and the information flows among these events.
5 Preparing overview activity diagrams Steps for preparing overview activity diagrams : Preliminary steps : Step 1 : Read the narrative and identify key events. Step 2 : Annotate the narrative to clearly show event boundaries and event names.
6 Steps for preparing the activity diagrams: Step 3 : Represent agents participating in the business process using swimlanes. Step 4 : Diagram each event. Show the sequence of these events. Step 5 : Draw documents created and used in the business process. Step 6 : Draw tables (files) created and used in the business process.
7 Events Table Events : Part of a business process. Typical events in a business process include agreements with customers / suppliers / employees for goods and services, receiving and providing goods and services, recognizing claims, and paying or receiving cash.
8 EVENTS TABLE Guidelines for recognizing events : Guideline 1 : Recognize the first event in a process occurs when a person or department within an organization becomes responsible for an activity. Guideline 2 : Ignore activities that do not require participation by an internal agent.
9 Guideline 3 : Recognize a new event when responsibility is transferred from one internal agent to another. Guideline 4 : Recognize a new event when a process has been interrupted and resumed later by the same internal agent. Guideline 5 : Use an event name and description that reflects the broad nature of the event.
10 SOURCE DOCUMENTS Information about business events was first captured in source documents. Example of source documents : –Sales orders –Packing slips –Invoice –others
11 JOURNALS Data about events with accounting significance are aggregated and recorded in journals. The journal entries are posted to the general ledger.
12 Organizing Data in an AIS One important motivation for identifying events from narrative description of a business process is that AIS data are closely related to these events.
13 Files in Computerized AIS Information about file design can be collected from a variety of sources, including systems documentation, manuals accompanying the software that manages the file & interviews with the employee responsible for a company’s information system.
14 File concepts: Entity Field Record File Transaction file Master file Reference data Reference field Summary data Summary field
15 Types of Files & Data Two important types of data files are Master files Transaction files
16 Types of Files & Data Two important types of data files are Master files Transaction files
17 Master files have the following characteristics: They store relatively permanent data about external agents, internal agents or goods & services. They do not provide details about individual transactions Data stored can be characterized as either reference or summary data –Reference data are descriptive data that are relatively permanent & not affected by transactions. –Summary data are changed when events such as order & shipments, occur.
18 An AIS usually contains master files about three types of entities: Goods & services External agents Internal agents
19 Transaction files have the following characteristics: They store data about events They usually include a field for the date of the transaction They usually include quantity & price information Recall that events occur in a specific sequence in the revenue & acquisition cycles Any event about which information is needed should be recorded in a transaction file suitable for that type of event. If two events occur at the same time, the system designer can consider recording both events as a single record in a transaction file.