akamechan022 Posted March 18, 2016 Share Posted March 18, 2016 hello i am a complete newbie on sql and i want to know why do we need to use one to one,one to many/many to one and many to many in linking tables sorry i am just curious thanks to those who will help :-) Link to comment Share on other sites More sharing options...
dsonesuk Posted March 18, 2016 Share Posted March 18, 2016 (edited) Basically to reduce duplication, and make it more manageable, instead of listing many branches under one company in a single record row, where you would end up with several columns for branches used for one company, then another company with very few branches would end up with remaining columns empty, wasting space and unnecessarily increasing database size. By listing all brances in a many to one table and associating those branches with a one to many company id (containing singular info such as company website, email etc) you reduce having empty columns with less chance of duplicating branches associated with that company. Edited March 18, 2016 by dsonesuk 1 Link to comment Share on other sites More sharing options...
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