Unterschiede

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--- modul:m290:learningunits:lu03:loesungen:l04 [2024/08/27 12:48] – vdemir
+++ modul:m290:learningunits:lu03:loesungen:l04 [2024/10/02 15:13] (aktuell) – vdemir
@@ Zeile 1: / Zeile 1: @@
-====== LU03.A04 - ERD: Travel DB ======
+====== LU04.S04 - ERD: Travel DB ======
+  * The attribut must be taken over and added with data-types and constraints (primary keys)
+  * The relations must be realized as relation tables, that connect the base tables
+  * The attributes of the relation tables are: id, and the primary key of each base table as foreign key
+  * Finally, the cardinalities must be added, which show how the relationships between the tables actually are.
+  * The attribut must be taken over and added with data-types and constraints (primary keys)
-Below figure of a conceptual datamodel illustrates  the basic database structure of a Travel_DB. It consists of three base tables and two relations.
-{{:modul:m290:learningunits:lu03:loesungen:screenshot_2024-08-27_123029.png|}}
+{{:modul:m290:learningunits:lu03:loesungen:s04.drawio.png?1500|}}
+===== Case Study =====
+The relation between **Countries** and **Continents** is a so called **many-to-many-relation = n:m-relation**. In the following illustration, we can see, that one continent consists of several countries. For some countries, however, this relationship applies in both directions, e.g. Turkey and Russia, which are located in both Asia and Europe.
+{{:modul:m290:learningunits:lu03:loesungen:country-relations.png?1000|}}
-==== Task ====
-Your assignment is to analze the given ERD (coneptual datamodel), which is in fact the last step before creating the actual db ins our Mysql database system, and draw the ERD as a logial data model. The subtasks are:
-  - develop the logical datamodel (tables, attributes, data types, fk/pk) by using the Crow's Foot Notation
-  - realize the realation as ralation tables (id, fk_tab1, fk_tab2, ...)
-  - finalize the ERM by adding the cardinalities (1:1, 1:many, ...)
 ===== Vocabulary =====
 ^ English ^ German ^
-| prerequisite | Grundvoraussetzung |
+| constraint | Einschränkung, Bedingung|
 | given | gegebene, vorausgesetzt |
+| case study | Fallbeispiel |
 ----
 [[https://creativecommons.org/licenses/by-nc-sa/4.0/|{{https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png}}]] Volkan Demir