---------------- is used to retrieve tuples from the relation.

Related MCQs

• A                  on an attribute of a relation is a data structure that allows the database system to find those tuples in the relation that have a specified value for that attribute efficiently, without scanning through all the tuples of the relation.
• Which one of the following provides the ability to query information from the database and to insert tuples into, delete tuples from, and modify tuples in the database?
• Given the relation Supplier(s_id, p_order, s_name, qty) Given that there is a unique s_name for each s_id and that s_id, p_order is a composite key, find the correct statement among the following: i. this relation is a BCNF ii. this is 3 NF relation iii. this is a 2 NF relation iv. this is a 1 NF relation
• In a                            operations do not wait for requests to produce tuples, but instead generate the tuples eagerly.
• Suppose now that R(A,B:) and S(A,B:) are two relations with r and s tuples, respectively (again, not necessarily distinct). If m is the number of (not necessarily distinct) tuples in the result of the SQL query: R intersect S; Then which of the following is the most restrictive, correct condition on the value of m?
• The number of tuples in a relation is called it’s …………. While the number of attributes in a relation is called it’s ………………..
• An attribute in a relation is a foreign key if the                key from one relation is used as an attribute in that relation.
• An attribute in a relation is a foreign key if the _______ key from one relation is used as an attribute in that relation.
• A attribute in a relation is a foreign key if the _______ key from one relation is used as an attribute in that relation .
• A            is a property of the entire relation, rather than of the individual tuples in which each tuple is unique.