ANSWER : Ternary

Explanation : The given mapping is an example of ternary relationship of Patient Treatment with three entities, viz., Patient, Physician and Treatment.

ANSWER : Transitive dependency

Explanation : A functional dependency between two or more non-key attributes is called a transitive dependency.

ANSWER : The key must indicate the row�s position in the table

Explanation : A candidate key (i) must uniquely identify the row (ii) must indicate the row�s position in the table (iii) must be non-redundant and (iv) (iv) One of the primary key. A candidate key does not indicate the row�s positon in the table. Hence option (b) is the answer.

ANSWER : Both (opt1) and (opt3) above

Explanation : The equi-join is a join in which records are retrieved based on whether the join fields have matching values in both tables. That may seem like just a definition of a join, but it isn't. An example of a non-equal join is a join where records in the first table are joined to those records in the second table where the joined field in the first table is greater than (instead of equal to) the joined field in the second table (or less than, or anything besides equal to). Naturally, this returns more records than an equi-join. A natural join is one in which only one of the two tables� joined fields is returned. Since these two fields are by definition identical in an equi-join, it is redundant to include both. For a non-equal join, it is important to include both of those fields. So, equi-joins and natural joins go together.