Re: One to One Relationship

>>>>> "Wayne" == Wayne Hinch <hinchy2000_at_lineone.net> writes:

 Wayne> I.e. Would you have a Customer table and then a Payment Method
 Wayne> table or merge them together. I was thinking from the point of
 Wayne> view whereby is it easy to make an enhancement to two tables
 Wayne> (Customer and Payment Method) when such functionality is
 Wayne> needed to hold two 'Payment Methods' for one customer (Two
 Wayne> different credit cards). Whereas merging the tables together
 Wayne> it would be alot of work to implement the functionality
 Wayne> above. Also what about security?

I thought we were talking about a 1:1 relationship - what you outline above is not a 1:1 relationship - the customer to payment method is a 1:many relationship and therefore should be in two different tables.

If its a true 1:1 relatinship, nothing is lost by merging into one table from a theoretical standpoint. However, as others have pointed out, breaking a large table into two or more can have performance advantages and offer additional levels of security etc.

Tim

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Tim Cross
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