What does the term “Tuple” Mean in Relational Databases?

Question

Please explain what is meant by tuples in sql?Thanks..

Answer 1

It's a shortened "N-tuple" (like in quadruple, quintuple etc.)

It's a row of a rowset taken as a whole.

If you issue:

SELECT  col1, col2
FROM    mytable

, whole result will be a ROWSET, and each pair of col1, col2 will be a tuple.

Some databases can work with a tuple as a whole.

Like, you can do this:

SELECT  col1, col2
FROM    mytable
WHERE   (col1, col2) =
        (
        SELECT  col3, col4
        FROM    othertable
        )

, which checks that a whole tuple from one rowset matches a whole tuple from another rowset.