====== LU04.S02 - ERM: Travel DB ======

For this scenario, the following entity(-types) are identified:

1. Country
  * Attributes
    * CountryID (Primary Key)
    * CountryName
    * ContinentName

2. Trip
  * Attributes
    * TripID (Primary Key)
    * CountryID (Foreign Key)
    * StartDate
    * EndDate
    * Price
  * Relationships:
    * Country: A trip occurs in one country.
    * Duration: Calculated as the difference between EndDate and StartDate.

3. Continent
  * Attributes: 
    * ContinentID (Primary Key)
    * ContinentName
  * Relationships:
    * Country: Each country is located on one continent.

4. Relationships:
  * One-to-Many:
    * A Continent can have many Countries.
    * A Country can have many Trips.


5. ERM in Crow's feet notation 
  * Continent (1) ————< has >———— (∞) Country
  * Country (1) ————< hosts >———— (∞) Trip

{{:modul:m290:learningunits:lu03:loesungen:lu03.l02.png?1000|}}

===== Vocabulary =====
^ English ^ German ^ 
| prerequisite | Grundvoraussetzung |
| given| gegebene, vorausgesetzt |

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[[https://creativecommons.org/licenses/by-nc-sa/4.0/|{{https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png}}]] Volkan Demir