Unique contraint and index

Dear all,

When I define a unique contraint like

ALTER TABLE Documents ADD CONSTRAINT Documents_pk PRIMARY KEY (id,bid);

will that be enough to prevent full table scans ?
Or should I also define the index

CREATE INDEX DocumentsI ON Documents(id,bid);


the primary key constraint will implicit create the index. If the index will be usefull to prevent full table scans depends on the query. You can use explain to check.

And yes: this is a germany speaking forum, can we switch to german?