key questions
Posted: Mon Aug 11, 2003 8:59 pm
i'm being told more than one primary key is too many.
i need a set of things to be unique in three tables.. i've noticed i can call things either "unique" or "unique key"
i have questions....
1: what's the difference between those?
2: why have i seen examples where you end a line with "primary key" but none like that with "unique" or "unique key", and the only ones with unique are indexes?
3: why does "unique" have to have a name and a feild? is there a way to get it like making a primary key like when you define it inline (and why do i get the feeling that is what the difference between "unique" and "unique key" is)?
i need a set of things to be unique in three tables.. i've noticed i can call things either "unique" or "unique key"
i have questions....
1: what's the difference between those?
2: why have i seen examples where you end a line with "primary key" but none like that with "unique" or "unique key", and the only ones with unique are indexes?
3: why does "unique" have to have a name and a feild? is there a way to get it like making a primary key like when you define it inline (and why do i get the feeling that is what the difference between "unique" and "unique key" is)?