[postgis-users] Dilemma: is gid really useful in a geoDB?

[Antonello]

Hi list,

I have a dilemma: is gid really useful in a geoDB?
I am building a geodb for several harbor. When I create a layer(table 
with geometry) in postgis, I need a gid like a primary key, or I can use 
a different one? Can I  use several field of from the table like a 
primary key?

I am not new in the gis, but why in almost all geoDB I saw there is a 
gid?! Is it really necessary? Do it come from shapefile standards?

For example QuantumGIS doesn't work if the layer has only one primary 
key, there are other application that don't work like qGis?

Thanks a lot, Antonello