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Database Table E-R Entity Relationship Layout - please make suggestions and/or improvements ?

Posted By:      Posted Date: April 10, 2011    Points: 0   Category :ASP.Net

Not quite sure where to post this, but need some help defining a schema and E-R modelling, I'm not sure if I'm maybe making it too complex... 15 Tables in total right now




I have a store which Buys, Sells and Repairs - Laptops and Mobiles and Video Game Consoles and Printers.

This is a walk-in store, so customers can pay cash (and not have their details recorded) or they can pay by card. 


When buying therefore, if ordering via the Internet, customers will have their details recorded and added to the database, but if buying in the store, customers are unlikely to have their details recorded when buying unless they are making a return.

Customers will always have their details recorded when arranging a Repair.


I think I may need separate Orders and Sales tables, because Sales may be connected through an EPOS system, but Orders refers to internet orders, I'm not quite sure about this just now.


All items marked with * denote foreign keys.

So far I have the following table layouts, I'm sure I have missed something:




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