table design question

I'm using mysql and php to design a shopping cart.

In looking at work that others have done I noticed that some have a base set of tables for products, orders, etc and duplicate the tables for each store.

The approach I would tend to take (having used other development tools) would be to attach a store_id field to each table and keep all the data in for all the stores in the same tables.

Can anyone comment on the benefits/drawback of each approach?

Thank you-

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Staci Schipporeit
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