====== LU04.S06 - ERM vs. ERD ======

===== Prerequisites  =====
  * Work type: Peer
  * Means of aid: only teaching materials, no use of ai.
  * Timeframe: 5 Minutes
  * Expected result: A Word/PDF file with an a comparison of the terms ERM vs. ERD. 

===== Task  =====
Compare both terms, ERM and ERD,  and describe the purpose of each, and find at least 2 similarities and 2 differences.

**ERM**
  * Description: First step to find the entities and the correlations between them.
  * Purpose: Blueprint of the business cases

**ERD**
  * Description:Identification of details, such as data-types, relation-table and the cardinality 
  * Purpose: construction plan, ready to build up the data-base physically

**Similarties**
  * Both notation methods are used to describe the data-base structure of the business cases
  * Entity = rectangle
  * Cardinalities: 1:1, 1:n, n:m
  * Entities have attributes

 **Differences:**
  * Relations:
    * ERM: rhomb
    * ERD: relalation-table
    * ERD: Described in the Crow's foot notation
  * Attributes: 
    * ERM: bubbles above, which are connected with the entity
    * ERD: As details in the Entity, including data-type
    * ERD: Memory amount is describes within the data-type defintion

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

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