Re: [SQL] database design SQL prob.

Thus spake Stuart Rison
> Currently, in postgreSQL, primary keys are created as a UNIQUE index on the
> field(s) that form the primary key.
>
> This means that there is no difference between explicitely declaring a
> PRIMARY KEY in your table definition or using the CREATE UNIQUE INDEX
> command.

Not completely accurate. Create some tables using both methods then
run the following query.

SELECT pg_class.relname, pg_attribute.attname
FROM pg_class, pg_attribute, pg_index
WHERE pg_class.oid = pg_attribute.attrelid AND
pg_class.oid = pg_index.indrelid AND
pg_index.indkey[0] = pg_attribute.attnum AND
pg_index.indisprimary = 't';

This will give you a list of the primary keys if you declare them as
primary at creation time. The ones created with just a unique index
won't be displayed.

While I am on the subject, anyone know how to enhance the above query
to display all the fields when a complex primary key is defined? The
above assumes that all primary keys are one field per table.

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