LU04.S07 - ERD: Reingineering of an existing database

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.

1. We beginn the diagramm by identifying the entities. these are tables without any foreign keys:
   • Customers
   • Categories
   • Employees
   • Shippers
   • Suppliers
2. Then we determine the attributes and the data-types of each entity (-table).
3. We continue with the analysis of the relations. These are tables, which have foreign keys in their attribute list.
   • Orders
   • OrderDetails
   • Products
4. Finally, we connect the tables with each other in the right fashion and determine the cardinalities (1:1, 1:n, n:m)

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