Re: difrent id in a relational DB?? how?

[Peter Brawley]

> i want the id for shop 1 to be form 1 to 5 and for shop 2 if i have there 3 customers the id should be from 1 to 3

What purpose would that serve? Primary keys have just one function: uniquely identify the rows they're in. It's a design mistake to load them down with other significance.

shops( shopID int unsigned primary key, ...)
customer( custID int unsigned primary key, ...)
products( prodID int unsigned primary key, 
          shopID int unsigned,
          custID int unsigned,
          foreign key(shopID) references shops(shopID),
          foreign key(custID) references shops(custID)
)