If we want to retain all duplicates, we must write                  in place of union.

Related MCQs

•                              which increases the number of I/O operations needed to write a single logical block, pays a significant time penalty in terms of write performance.
• 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?
• The                        policy, allows the system to write modified blocks to disk even if the transactions that made those modifications have not all committed.
• Any recursive view must be defined as the union of two subqueries: a                query that is nonrecursive and a                      query.
•                    is the time from when a read or write request is issued to when data transfer begins.
•                        is popular for applications such as storage of log files in a database system since it offers the best write performance.
• In case the buffer manager do not write the blocks properly then the buffer manager uses
• Which join refers to join records from the write table that have no matching key in the left table are include in the result set:
•                          denotes the largest timestamp of any transaction that executed write(Q) successfully.
• The               operation performs a set union of two “similarly structured” tables