Outerjoin

Outerjoins

An attribute of the join operator is that it is possible for certain tuples to be "dangling"; that is, they fail to match any tuple of the other relation in the common attributes. Dangling tuples do not have any trace in the result of the join, so the join may not represent the data of

Natural Joins / Outerjoins

As we recall from Natural Joins / Theta-Joins, a natural join differs from a theta-join in that: 1. The join condition is that all pairs of attributes from the two relations having a common name are equated, and there are no other conditions. 2. One of each pair of equated attributes is projected out.

Page 0 of 1 Previous 1 Next