Question

29. Create the table that would result from applying the SELECT and PROJECT relational operators to the CHARTER table to return only the CHAR_TRIP, CHAR_PILOT, and CHAR_COPILOT attributes for charters flown by either employee 105 or employee 109.

30. Create the table that would result from applying the SELECT and PROJECT relational operators to the CHARTER table to return only the CHAR_TRIP, CHAR_PILOT, and CHAR_COPILOT attributes for charters flown by both employee 105 and employee 109.

31. Create the table that would result from applying a DIFFERENCE relational operator of your result from Problem 29 to your result from Problem 30.

PLEASE only show the relational algebra equation and not the resultant tables.

Answer 1

29.   ( CHAR_TRIP,CHAR_PILOT,CHAR_COPILOT(CHARTER)="105" OR "109"(CHARTER));

So from above relational algebra we get tuples with attributes of CHAR_TRIP,CHAR_PILOT,CHAR_COPILOT which has either employee 105 or 109.

30.   ( CHAR_TRIP,CHAR_PILOT,CHAR_COPILOT(CHARTER)="105" AND "109"(CHARTER));

Here we get tuples with attributes of CHAR_TRIP,CHAR_PILOT,CHAR_COPILOT which has both employee 105 and 109.

31.   ( CHAR_TRIP,CHAR_PILOT,CHAR_COPILOT(CHARTER)="105" OR "109"(CHARTER)) -  ( CHAR_TRIP,CHAR_PILOT,CHAR_COPILOT(CHARTER)="105" OR "109"(CHARTER));

Here we get table which is has only employee of 105 or 109 but not the tuple having both 105 & 109