Re: Composite Keys

RPK wrote:
> First, can a primary key field be only one? I mean can I define a primary
> containing two fields.

As many as you like :)

>
> I have a table called "Payments" where there are two fields, "ReceiptNo" and
> "PaymentDate". If I take "ReceiptNo" only as a primary key then chances are
> of "primary key violation". Because in some places the receipt books have
> numbers that start with 1. I mean Receipt Book 1 nos. 1-100. Receipt Book 2
> nos. 1-100, and so on.
>
> So I want to take ReceiptNo and PaymentDate as primary key field. Is it
> possible to define composite key in PGSQL. Please also suggest if any other
> approach would be fine.

CREATE TABLE payments (receiptno serial, paymentdate date, primary key
(reciptno,paymentdate))

Sincerely,

Joshua D. Drake

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