System Analysis and Design:SA Week 4: Lecture 1012 Date: 25112550 Time: 14'0017'00

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?????????????????????????System Analysis and
DesignSAWeek 4 Lecture (10-12)Date
25/11/2550 Time 14.00-17.00
By D.Sommit (B.Sc Medical Record Science
Mahidol University M.Sc
Information Technology (IT) Ubon. University)
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Topic

• ??????????????? (Types of Models)
• Entity-Relationship Diagrams (ERDs)
• ??????????????? (Data Dictionary)
• ????????????????? Data Flow Diagram (Context
  Diagram DFD Level 0)

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??????????????? (Types of Models)

• SA ????????????????????????? ?????????????????????
  ???????
• ???????? ?????????????????? ??????????????????????
  ?????????????????????????????????
• ???????? 3 ?????? ???
• 1. ????????????????????? (Mathematical
  Models)
• 2. ???????????????????????????
  (Descriptive Models)
• 3. ?????????????? (Graphical Models)

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??????????????? (Types of Models)

• 1. ????????????????????? (Mathematical Models)
• ??? ??????????????????????????????????
  ?????????????????? ???????????????????????????????
  ????????????? ???????????????????
  ??????????????????????

- X
f (n)
Connections(n2-n)/s)
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??????????????? (Types of Models)

• 2. ???????????????????????????
  (Descriptive Models)
• ???????????????????????????????????
  ???????????? ?????????? ?????????????????????
  ?????????????????????????????????????? (Pseudo
  code) ????????????????????????????? (Structure
  English) ?????????????????????????????????????????
  ????????????????

Description Xxxxxxxxxxxxxxxxxxxxxx Xxxxxxxxxxxxxxx
xxxxxxx Xxxxxxxxxxxx xxxxxxxxxxxxxxxxxxxxx
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??????????????? (Types of Models)

• 3. ?????????????? (Graphical Models)
  ????????????
• ???????????????????????????????????????
  ???????????????
• ???????????? ????????????????? ????????????
  ???????
• ?????????????????????????? ???????????????????
  ??
• ??????????????????

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??????????????? (Types of Models)
.. .. ..
.. .. ..
Analysis
Requirements Specification
Logical Model
??????????????????????????????????????????????????
?????????????? ???????????????????????????????????
??????????????????????????????????????
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Entity-Relationship Diagrams (ERDs)
Traditional approach to system development
techniques
Emphasis on data requirement for a new system
Data Storage requirement
Data entities or Table
Relationships among the Data entities
Attribute or Field
Entity-Relationship Diagram (ERDs)
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Entity-Relationship Diagrams (ERDs)
Syntax
Entity Name
????? (Nouns)
Data Attribute,Attribute
Entity Name
Students ID_Stud Name Surname Address Major
Data Attribute,Attribute
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Entity-Relationship Diagrams (ERDs)
Syntax Cardinality
Exactly one (Mandatory) ????????????????
Zero or one (Optional) ???????????????? One
or more ???????????????? Zero or more
????????????????
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Entity-Relationship Diagrams (ERDs)
Syntax Cardinality
Zero Or More (Optional)
Exactly One (Mandatory)
One Or More (Mandatory)
Zero Or One (Optional)
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Entity-Relationship Diagrams (ERDs)
Example Syntax Cardinality
has a
Student
Transcript
works for
Professor
Department
chairs
Professor
Department
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Entity-Relationship Diagrams (ERDs)
Example Syntax Cardinality
attends
Student
Section
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System Sequence Diagram (SSD)
Entity-Relationship Diagrams (ERDs)

• ????????????????????? (Prepare ERDs)
• 1. ???????????? Entities ?????????????
  (involed) ??? Externals Entities and Internal
  Entities ??? Requirements
• 2. ???????????????? ??????? Entities
• 3. ???????????? Attributes ????????????????
  Requirements

Flow of prepare a ERDs
Search and Definite Entities (Conceptual ERDs)
1.
2.
Definite Relationship
3.
Search and Definite Attributes
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Entity-Relationship Diagrams (ERDs)
Step I Search and Definition Entities
(Conceptual Conecptual ERD
Bill
BuyGoods
Customer
Stocks
Employee
Order
Payroll
Internal Entity
External Entity
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Entity-Relationship Diagrams (ERDs)
Step II Definition Relationship and Cardinality
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Entity-Relationship Diagrams (ERDs)
Step III-1 Search and Definite Attribute

• 1. Customer
• 1.1 ID_Customer
• 1.2 Name , 1.3 Surname ,1.4 Address
• 2. BuyGoods
• 2.1 ID_Employee 2.2 ID_Customer
• 2.3 Buy_Date , 2.4 Time_Date ,2.5 Mount
• 2.6 ID_Goods , 2.7 ID_User
• 3. Bill
• 3.1 ID_Goods , 3.2 ID_Mount 3.3 Sum
• 3.4 Date_Bill , 3.5 Time_Bill 3.6
  Bill_Number

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Entity-Relationship Diagrams (ERDs)
Step III-2 Search and Definition Attribute
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Additional attribute and Data type
Explanation
Size in bits
Range
Data type

• Byte 8 -128 to 127
  small amount o f data
• Char 16
  names of character data
• Boolean 1 true of false true
  or a false value
• Short 16 -32768 to 32767
  smaller numbers
• Double 64
  large numbers
• 
  value decimals

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Additional attribute and Data type
Size in bits
Range
Data type
Explanation

• Int 32 large
  numbers
• Float 32 number
  value
• 
  decimal

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??????????????? (Data Dictionary)

• ??? ???????????????????????????????????????
  ???????? ???????????????????????????
  ?????????????????? , ????????????????????? ,
  ?????????? , ?????????????? ????????????
• ????????????????????? (Ralation Name or
  Entity)
• ??????????? (Attribute)
• ???????????????? (Data Description)
• ???????????????? (Attribute Domain)
• ???????? (Primary Key) , ???????
  (Foreign Key) , ?????????? (Data Type)

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??????????????? (Data Dictionary)

• ??????????????????????????????????????????????????

????????? (Entity Name) .. ????????
?? (Description) ????????????????????.
Attribute Reference
Entity Reference
FK
PK
Attribute
Type
No.
Description
Attribute Domain
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??????????????? (Data Dictionary)

• ??????????????????????????????????????????????????

????????? (Entity Name) Customer ??????????
(Description) ????????????????????
?????????????
Attribute Reference
Entity Reference
FK
PK
Attribute
No.
Description
Attribute Domain
Data Type
??????????????????
1
yes
ID_Customer
Char(10)
??????????
Char(20)
2
Name
????????????????????
Birthdate
3
Date(8)
1???,2????
Char(1)
???
Sex
4
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??????????????? (Data Dictionary)
????????? (Entity) BuyGoods ??????????
(Description) ????????????????????
????????????????
Attribute Reference
Entity Reference
Data Type
Attribute Domain
FK
PK
Attribute
No.
Description
1
Employee
yes
ID_Employee
???????????????????
ID_ Employee
Char(6)
2
Name
Char(20)
???????????
Surname
??????????????
3
Char(20)
?????????????????????
Salary
4
Float
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Entity-Relationship Diagrams (ERDs)

• Summary ERDs are 2 main component2
• 1. Design ERDs
• 2. Design Data Dictionary

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End