Re: confused newbie (to pg not db's)

mike <mike@redtux1.uklinux.net> writes:
> CREATE TABLE public."Invoice_Header"                     ^^^^^^^^^^^^^^^^

> I am trying to make Inv_ID a primary key as follows

> alter table Invoice_Header ADD CONSTRAINT PK_inv PRIMARY KEY (Inv_ID)             ^^^^^^^^^^^^^^

> which runs without error, but nothing changes

I think you have tables named "Invoice_Header" and "invoice_header",
and the latter table is what's getting affected by your ALTER.  If you
are going to use mixed-case names then you have to be consistent about
double-quoting them all the time.
        regards, tom lane