M3 Level Listening part Sample - mlt- · PDF fileေရွးအခါကေလွသူႀကီးနဲ႔ကုန္သည္ႀကီးဟာ
M3 - Part 3
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Transcript of M3 - Part 3
M3 - Part 3
Adrian MacCallum
&
Rodger Morash
What is Data Modeling?
• Data Modeling is a technique for organizing and documenting a system’s DATA.
Why is data modeling important?
• It removes biases.
• It reduces the risk of missing business requirements.
• It allows the system analyst to communicate with end users.
What is a key-based data model?
• This model will eliminate non-specific relationships, add associative entities, include primary, alternate keys, and foreign keys, plus precise cardinalities and any generalization hierarchies.
SAVINGS BOND PURCHASEKey Data
BondPurchaseDate [PK1]EmployeeNumber [PK2]BondOwnerSocialSecurityNumber [PK3]
EMPLOYEE EMERGENCY CONTACTKey Data
EmployeeNumber [PK1]ContactName [PK2]
ContactHomePhone [PK3]
ROOMKey Data
Site [PK1]BuildingCode [PK2]RoomNumber [PK3]
EMPLOYEE ACTIVITYKey Data
EmployeeNumber [PK1]ActivityDate [PK2]ActivityCode [PK3] UNITED WAY CONTRIBUTION
Key DataUWContributionDate [PK1]EmployeeNumber [PK2]
EMERGENCY CONTACTKey Data
ContactName [PK1]ContactHomeAddress [PK2]
BUILDINGKey Data
Site [PK1]BuildingCode [PK2]
EMPLOYEEKey Data
EmployeeNumber [PK1]
DEPARTMENTKey Data
DepartmentNumber [PK1]
SITEKey Data
Site [PK1]
COMPANY POST OFFICEKey Data
MailStop [PK1]
Is an
ContainsMakes
Makes
Has
Has located on it
Is assigned
Contains
Contains
Is located at
Generates