The               operation performs a set union of two “similarly structured” tables

Related MCQs

• View the Exhibit and examine the data in the EMPLOYEES tables. Evaluate the following SQL statement: SELECT employee_id, department_id FROM employees WHERE department_id= 50 ORDER BY department_id UNION SELECT employee_id, department_id FROM employees WHERE department_id= 90 UNION SELECT employee_id, department_id FROM employees WHERE department_id= 10; What would be the outcome of the above SQL statement?
• Once the lower-level lock is released, the operation cannot be undone by using the old values of updated data items, and must instead be undone by executing a compensating operation; such an operation is called
• An Oracle                      is a set of tables and views that are used as a read-only reference about the database.
• An Oracle __________ is a set of tables and views that are used as a read-only reference about the database.
• View the Exhibit and examine the structure of the EMPLOYEES and DEPARTMENTS tables. Which SET operator would you use in the blank space in the following SQL statement to list the departments where all the employees have managers? SELECT department_id FROM departments ____ SELECT department_id FROM employees WHERE manager_id IS NULL;
• The relational model is based on the concept that data is organized and stored in two-dimensional tables called ……………………….
• In which ways two tables may be related:
• The          connective tests for set membership, where the set is a collection of values produced by a select clause. The           connective tests for the absence of set membership.
• If an entity set is a lower-level entity set in more than one ISA relationship, then the entity set has
• A system is in a              state if there exists a set of transactions such that every transaction in the set is waiting for another transaction in the set.