Example with Multiple Transformations Query:Find the names of all instructors in the Music department who have taught a course in 2009,along with the titles of the courses that they taught IIname,titledept_name=Music"year=2009 (instructor凶(teaches凶Πcourse_ia,tie(course))） Transformation using join associatively(Rule 6a): IIname,title(dept_name=Music"gear=2009 ((instructor凶teaches)XIΠcourse_ia,te(course)》 Second form provides an opportunity to apply the "perform selections early"rule,resulting in the subexpression deptname=Music"(instructor)year=2009(teaches) Database System Concepts-6th Edition 1.16 ©Silberschat乜，Korth and SudarshanDatabase System Concepts - 6 1.16 ©Silberschatz, Korth and Sudarshan th Edition Example with Multiple Transformations Query: Find the names of all instructors in the Music department who have taught a course in 2009, along with the titles of the courses that they taught name, title(dept_name= “Music”year = 2009 (instructor (teaches course_id, title (course)))) Transformation using join associatively (Rule 6a): name, title(dept_name= “Music”gear = 2009 ((instructor teaches) course_id, title (course))) Second form provides an opportunity to apply the “perform selections early” rule, resulting in the subexpression dept_name = “Music” (instructor)  year = 2009 (teaches)