Aliakbar Mohammadyari Ch.5 Data and Process Modeling Q. Describe data and process modeling concepts and tools During the data and process modeling, a systems analyst develops gra phi cal mo del s to sho w how the system tra nsf or ms dat a int o useful inf or mat ion . Ove ral l, the se too ls and model ing con cepts se rve to mak e dat a an d proce sses ea sier to vi sua li ze an d understand via diagrams (DFD), tables (Decision table), and charts (decision trees). Dat a and proc ess modeling involves three main tool sda ta !ow dia gr ams, a da ta di ct ionary , an d proces s descriptions. "ystems analysts use many graphical techni#ues to describe an information system. $ data !ow diagram (DFD) uses various symbols to show how the system transforms input data into useful information. Q. Explai n the dife rences bet ween Gane and Sar son and Y ordon s!mbols. Pro"ide examples o# s!mbols that represent processes$ data %ows$ data stores$ and entities. Diference is the slight shape diferences between the symbols like the rounding othe process symbo l. 1
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• *itchen +adgets sells a line o high,-uality kitchen utensils andgadgets. hen customers place orders on the company/s ebsite or through electronic data interchange (!DI)0 the systemchecks to see i the items are in stock0 issues a status message
to the customer0 and generates a shipping order to thewarehouse0 which lls the order. hen the order is shipped0 thecustomer is billed. "he system also produces various reports.
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● ,as-s
• ist #or elements sed in D*Ds$ draw the s!mbols$ andexplain how the! are sed.
• 2he four elements are eternal entity (the original source ofdata or the receiver of information), process (a series of steps
that manipulate data), data store (place to keep data for lateruse), and data !ow (describes the data and the informationelements passing between eternal entities, processes, anddata stores).
● Simpli#! the table !o 1st created. Describe the reslts.
Conditions 1 2 3 4 5 6
Student taken a safe drive course Y Y Y N N NStudent with a clean record Y Y N Y N N
Student is 23 or older Y N ' ' Y N
Elii!le to 5" #iscount $ $ $ $ $
Elii!le to 5" %onus discount $
&nelii!e to discount $
● Draw a simpli8ed decision tree that shows the discontrles.
Q. &hat are the pros and cons o# sing a decision table"erss a decision tree(
9hether to use a decision table or a decision tree often is a matterof personal preference. $ decision table might be a better way tohandle comple combination of conditions. On the other hand, a
decision tree is an e&ective way to describe a relatively.