A Non-Relational Representation (Cont.)
Companies
It has a name, head office, several subsidiaries, and a president.
| Company |
| CompanyID |
Name |
Street |
Location |
President |
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Subsidiaries
It has a name, office, manager, and employees.
| Subsidiary |
| CompanyID |
NameSubs |
Street |
Location |
Manager |
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⇓ aggregation ( [...]: tuple type and {...}: set type )
Company: [
Name: String,
Headoffice: Address,
Subsidiaries: { Subsidiary },
President: Employee ]
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|
|
Subsidiary: [
Name: String,
Office: Address,
Manager: Employee,
Employees: { Employee } ]
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Address: [
Street: String,
Location: String ]
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For aggregation, the name of a type can be directly referred in another type.
Because attributes are associated with named types, there is no longer a need for a foreign key clause as in the relational model.
Vehicles
It has a model name, color, and manufacturer.
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Vehicle: [
Model: String,
Manufacturer: Company,
Color: String ]
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