Extra tutorials

Precision Tools System• Precision Tools System: Precision Tools sells a line of high-

quality woodworking tools. When customers place orders on the company’s Web site, the system checks to see if the items are in stock, issues a status message to the customer, and generates a shipping order to the warehouse, which fills the order. When the order is shipped, the customer is billed. The system also produces various reports.

2

(draw your context diagram)

3ACCOUNTING

WAREHOUSECUSTOMER

0

Order System

Order

Payment

In-StockRequest

StatusMessage

Invoice Shipping Confirmation

Shipping Order

Inventory Reports

Level-0 DFD

4

1.0

CheckStatus

2.0

IssueStatus

Messages

3.0

GenerateShipping

Order

ACCOUNTING

CUSTOMER WAREHOUSE

4.0

Manage Accounts

Receivable5.0

ProduceReports

Order In-Stock Request

Status Data

Status Message

PendingOrdersD1

Order Data

Order Data

Shipping Order

Shipping Confirmation

Invoice

Payment

Accounts ReceivableD2

Accounting Data Accounts Receivable Data

Order Data

Inventory Reports

2

Modeling Logic with Decision Tables • Procedure for Creating Decision Tables

• Name the condition and the values that each condition can assume.

• Name all possible actions that can occur.• List all possible rules.• Define the actions for each rule.• Simplify the table.

Q1: Create a decision table- Students Campus Burglar Alarm

When a burglar alarm sounds, if it is in one of students’ houses where alarm sounds every week, ignore it. Otherwise have a look outside and if the house looks not broken into and there is nobody moving inside it, ignore the alarm. Otherwise call police.

• List the resulting rules.

6

A1: Decision Table – Students Campus Burglar Alarm

Rule Stub

Rule 1 Rule 2 Rule 3 Rule 4

Condition Stub One of those houses Y Y N N

Suspicious activity Y N Y N

Action Stub Ignore X X X

Call Police X

7

A1: Simplified Decision Table – Students Campus Burglar Alarm

Rule Stub

Rule 1 Rule 2 Rule 3

Condition Stub One of those houses Y N N

Suspicious activity - Y N

Action Stub Ignore X X

Call Police X

8

A1: Resulting Rules- Students Campus Burglar Alarm

• Rule 1: if one of those houses then ignore• Rule 2: if not one of those houses and suspicious activity then call police• Rule 3: if not one of those houses and not suspicious activity then ignore

Note: rule 2 will work just as well if skip the first check:• Rule 2: if not suspicious activity then ignore

9