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--- modul:m290:learningunits:lu03:aufgaben:a07_erd [2024/08/26 15:06] – angelegt vdemir
+++ modul:m290:learningunits:lu03:aufgaben:a07_erd [2024/10/17 13:27] (aktuell) – vdemir
@@ Zeile 1: / Zeile 1: @@
-====== LU03.A04 - ERD: Travel DB ======
+====== LU04.A07 - ERD: Reingineering of an existing database  ======
+From time to time, we may need to analyze an existing database in order to optimize the structure, e.g. for the next software version.
-After developing our conceptional data model, the next step to establish a physical data base is shape a ERD, the Entity Relationship Diagram.
 ===== Prerequisites  =====
   * Work type: Peer
-  * Means of aid: only teaching materials, no use of ai.
+  * Means of aid: [[https://www.w3schools.com/sql/trysql.asp?filename=trysql_editor | W3Schools-SQL-Editor]]
-  * Timeframe: 10 Minutes
+  * Timeframe: 45 Minutes
-  * Expected result: A Word/PDF file with an ERD that visualises the given business case.
+  * Expected result: ERD as a PDF-File, that describes the content of the given date-base in Crow's Foot Notation.
 ===== Task  =====
-Create an ERD to the given ERM in the Crow's Foot Notation.
+Go to the W3Schools-Website, to the SQL-Editor, and analyze the existing data-structure. Create furthermore an ERD, that describes the existing data-structure in the Crow's Foot Notation.
-  * Identify additional attributes
-  * Establish relation with inkl. the primary keys and foreign keys
-  * Connect the tables and finish your work by fixing the entities (0:1, :1, 0:n)
+{{:modul:m290:learningunits:lu03:aufgaben:screenshot_2024-09-12_151200.png?800| Given data-struture of W3Schools-SQL database}}
-===== Given Details =====
+  - Identify all enties.
-. Relationships:
+  - Add the attributes and the corresponding data-types to each entity.
-  * One-to-Many:
+  - Relate the tables to each other by analysing the primary keys and the foreign keys.
-    * A Continent can have many Countries.
-    * A Country can have many Trips.
+===== Solution =====
-. ERM in Crow's feet notation
+[[modul:m290:learningunits:lu03:loesungen:l07|Lösung]]
-  * Continent (1) ————< has >———— (∞) Country
-  * Country (1) ————< hosts >———— (∞) Trip
-. ERM visualisation
-{{:modul:m290:learningunits:lu03:loesungen:lu03.l02.png?800|}}
 ===== Vocabulary =====
@@ Zeile 36: / Zeile 24: @@
 | prerequisite | Grundvoraussetzung |
 | given| gegebene, vorausgesetzt |
 ----
 [[https://creativecommons.org/licenses/by-nc-sa/4.0/|{{https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png}}]] Volkan Demir