E-R Diagram (Entity Relationship Diagram)

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E-R Diagram(Entity Relationship Diagram)

• Boonrit kidngun

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E-R Diagram

• ??????????????????????????????????????????????????
  ???
• ????????????????????????????? Conceptual
• ??????????????????????????????????????????????????
  ??????????? Software ??????????????????????
  (?????????? Software)
• ????????????????????????????????????????

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????????????????? E-R Diagram ?????? Chen Model

• Entity
• ??????????????????????????????????????????????????
  ????????????????????
• ????
• ????? (???????, ???????, ???????,
  ????????,??????)
• ??????? (???????, ?????, ???, ???????)
• ????? (??????, ?????, ???????????,??????)
• ????????? (???????, ????????????,
  ???????????,????,???)
• ???????????????????????????????????????? Entity
  ?????????

???????
????????? Entity
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• ????????? ??? Entity ?? 2 ??????
• 1 Regular Entity ???????????????????? Strong
  Entity
• ???? Entity ????????????????????????? Entity
  ??????????????? ??????????????? Identity
  ????????????? ??????????? Entity ????
• 2 Week Entity
• ???? Entity ?????????????????????? Entity
  ???????????????

Customer
Order Detail
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????????? Strong Weak Entity
Student (Strong)
Subject (Strong)
???? ???? ???
45001 ???? ????????????
45002 ????? ?????
???????? ????????
01 ?????????
02 ?????????
Regis_Detail(Weak)
???? ?????????? ????????
45001 1/45 01
45002 1/45 01
45001 1/45 02
45002 1/45 02
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• Attributes
• ?????????????????????????? Entity
• ???? Attributes ??? ??????? ??????????
• ?????????????
• ????-???????
• ???
• ?????????
• ????????? Attributes ?????????????????
  ???????????? Attributes ??????????????
  ????????????????????? Entity ?????? ????

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• ???????? Attributes

Sex
Name
Employee
Emp_ID
Salary
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• Attributes ?????????????????? 6 ??????
• 1 Simple Attributes
• Attributes????????????????????????????????? ????
  ???,?????????
• 2 Composite Attributes
• ????????????????????? Simple ?????????????????????
  ??????? ???? ???????? ???????????????????????
  Attributes ???? ??? ????
• 3 Key Attributes
• ???? Attributes ??????????????????????????????
  Entity ??????? (??????????????)
• ????????? ER Diagram ?????????????? Attributes
  ??????? Key ????

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• 4 Single - Valued Attributes
• Property ????????????????????????????????????
  ???? Attributes ??? ??????????????? ??? ???? ????
  ???????? ??????????????????????????
• ????????????????? ????????????????????????
• 5 Multi - Valued Attributes
• ????????????????????? Single ?????????????????????
  ???????????? ???? ????????????????????????????????
  ?????????????????????????
• ????????????????????????
• 6 Derived Attributes
• ???? Property ??????????????????? ?????????????
  Property ???? ? ???? ?????????? ???????????
  Property ???????
• ????????????????????????

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• ??????????? Attributes ???????? ?

Composite
Name
Surname
Sex
Name_Surname
Birthday
Derived
Student
ID
Age
key
Tel
Multi - Valued
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• 3. Relationship
• ??????? Entity ?????????????????????????? 2
  Entity ??????
• ??????????????????????? Entity ????? Attributes
  ???????
• ??????????????????????????????????????????????????
  ????????????? (Diamond) ??????????????????????????
  ??????? ?
• ??????????????????????????????????????? Entity
  ???? ? ????

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• ???????? Relationship

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????????? Relationship

• 1. One-to-One Relationship
• ?????????????????????????????? Entity
  ?????????????????? ?????????????? Entity
  ??????????? ???????????????????????

1
1
Car
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????????? Relationship

• 2. One-to-Many Relationship
• ?????????????????????????????? Entity
  ?????????????????? ?????????????? Entity
  ??????????? ??????? 1 ??????

1
M
Car
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????????? Relationship

• 2. Meny-to-Many Relationship
• ???????????????????????????????? 1 ?????? ?????
  Entity ?????????????????? ?????????????? Entity
  ??????????? ??????? 1 ??????

M
N
Account
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• Composite Entity
• ???? Entity ?????????????????????????????????????
  ?? MM ??????? ??? 1M (???????? MM
  ???????????????????????????)
• ???? Composite Entity ?????????? Entity
  ???????????????????? Key Property ??????? 2
  Entity ???? ??????????????? ?
• ???? Key Property ??? Composite Entity ????? Key
  Property ??????? 2 Entity ??????????? (???? PK
  ??????????????? Super Key ????????)
• ???????????? Composite Entity ???
  ????????????????????????????????????????????????

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???????????????????????? MM ?????? 1M
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?????????????????????? E-R Model

• 1. ?????????????????????????????????????????
• ?????????????????????
• ?????????????????????
• ???????????????
• ?????????????????

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• 2. ????? Entity ???????????????????????
• ??????????????????????????????????????????????????
  ? ?????????????????????????? Entity
• ??????????????????? ? ???????????? Entity
  ???????????? ?????????????????????????????????????
  ???????????????????
• ??????????? Entity ?????????????? Entity
  ??????????????????????????????

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• 3. ??????????????????????????? Entity
• ???????? Entity ????????????????????????
  ??????????????????????????? ??????????????????????
  ????????
• One to One Relationship
• One to Many Relationship
• Many to Many Relationship

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• 4. ???????????????????? Entity
• ????????????????????? (Attributes) ?????? Entity
  ???????????????????? Attributes ?????
• ??????????????????????? Attributes
  ???????????????
• Composite Attributes
• Derived Attributes

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• 5. ???????? Primary Key ???????? Entity
• ??????????????? Entity ????? Entity
  ??????????????????????????????????????????????????
  
• ????????????????? Primary Key ???????

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?????????????????????????????? E-R Model

• Ex
• ??????????????????????????????????? 3 ??? ???
  ?????, ???????????, ???????????
• ??????????????????????????????????????? ?
• ??????????????????????????????????????? ? ??
• ???????????????????????????? ?????????????????????
  ?????????????????
• ?????????????????????????????????????????

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• ????? Entity ???????????????????????
• Entity Faculty ????????????????????
• Entity Department ?????????????????????
• Entity Teacher ????????????????????????
• Entity Subject ?????????????????????

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• ???????????????????????? Entity

1
M
1
M
1
M
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1
M
M
M
1
1
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• ????????????????? Entity
• Faculty
• Department

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• Teacher
• Subject

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• ???????? Primary Key ??? Entity
• Entity Faculty ??? Faculty_ID
• Entity Department ??? Dep_ID
• Entity Teacher ??? Teacher_ID
• Entity Subject ??? Subject_ID

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(No Transcript)
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?????????????????????????????? E-R Model

• Ex ???????? ER-Diagram ???????????????????
  ????ABC ???????????
• ??????
• ????????????????????????????????????????????
• ???????????????????????????????????????
• ???????????????????????????????????????????????
• ???????????????????????

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• ????? Entity ???????????????????????
• Entity Customer ???????????????????????
• Entity Employee ???????????????????????????
• Entity Product ???????????????????????
• Entity TypeProduct ???????????????????
• Entity Bill ????????????????????????

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• ???????????????????????? Entity

??
1
M
Employee
Bill
??
1
M
TypeProduct
Product
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??
M
M
Bill
Product
Bill_detail
M
1
1
M
Bill
Product
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• ????????????????? Entity

Emp_ID
Product_ID
Employee
Emp_name
Product
Product_name
salary
price
TypeProduct
TypeName
TypeID
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Cus_ID
Bill_No
Customer
Cus_name
Bill
Bill_date
Address
Emp_ID
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ER-Diagram ???????????????????
Product_ID
Product_name
Product_ID
Price_s
Detail_ID
Bill_No
price
Bill_detail
Bill_detail
1
1
M
M
Bill
Product
Bill_date
M
M
Amount
M
Emp_ID
??
Bill_No
??????
TypeName
1
??
TypeID
TypeProduct
1
1
Employee
Emp_name
salary
Emp_ID