A table that has associations with two other tables and is used indirectly as an association between those two tables. Also called linking table. key A column used to identify a record, often used as the index column for a table. left outer join A type of outer join in which all rows from the first-named table (the left table, which appears leftmost in the JOIN clause) are included. Unmatched rows in the right table do not appear. For example, you can create a left outer join between titles and the publishers tables to include all titles, even those you don't have publisher information for. Compare with inner join, outer join, and right outer join.