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Recent Writing

Database Modeling

2 min read

Model

Conceptual Model

  • Map and dict represent what system does
  • Technical consideration not necessary

Logical Model

  • Adaptation to the tailored system, ER Diagram
  • Use (MySQL), independent of what database
  • Denormalization we got lost, the person, why we don’t use that

Physical Model

  • Implementation
  • Queris gaming

Fundamental Of Conceptual Modeling

Input → A map and dictionary representing what system does → Output

TM

Definition

Everything is things and events We can connects objects through relationships

  • Event to resource: Involves a term
  • Resource to resource: Create something from one term to another
    • Application form
    • Create intermediate table, correlation, if 1 to many
  • Event to Event: a previous event is involved in a subsequent event
    • CircleCI
    • Left to right chronological
    • The intermediate table is also needed if 1 to many
  • Recursion

How to Create

  • Collect terms
    • Have primary identity (primary key)
  • categorize terms into events and resources
    • Event: Whether that event that has a date is not
    • Resource: anything else
    • Arrange events in chronological order, the most important is on the events
    • Events < resources → this is not a good model
  • establish relationships
    • add (R) on the left
    • State != value
      • Unoccupied, occupied
  • create sets from terms
    • sets must be in mutually exclusive OR relationship

Conclusion

Collecting terms Classify the collected nouns into events and resources to form entities construct relationship between terms null represents a state of not yet existing, changing as values are fullfiled create subsets to derive classification values carefully verify that the conceptual model written is semantically correct

Receipt

  • Store
  • address
  • phone
  • date
  • Registration Id
  • Item

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