Which process is used to prevent the current database operation from reading or writing a data
item while that data item is being accessed by another operation?
Consider the relations shown in the exhibit. Due to restructuring, the sales department has
been eliminated and the employees working in that department have been dismissed. All ID
information is stored as integers. Which SQL statement would be used to return a relation with all
information for the employees who have been dismissed?
Consider the Recreation relation in the exhibit. A data operation that changes one of the tuples
for Student_ID 1003 must be performed. It is necessary to change one of the activities from
swimming to tennis. The Student_ID and Activity attributes make up the primary key for the
Recreation relation. All related information must be altered, as well. Which SQL statement or
statements would best accomplish this?
Submit Cancel