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