Slide 10.19: Method example II (cont.)

Method Example II (Cont.)

Implement a method to allow a rectangle to be expanded or contracted by changing its pt2 value.

Display all rectangles in rects1 as they would look after being resized to have a new pt2 corner at (10, 10).

Apply the resizing operation to all rectangles in rects1 with pt1 at (1, 2) to increment pt2.x and pt2.y by 1.

The definition of point_t can be found from point_t.

SQL> CREATE TYPE  rectangle_typ  AS OBJECT (
  2    pt1  point_t,
  3    pt2  point_t,
  4    MEMBER FUNCTION  resize( p point_t )  RETURN  rectangle_typ );
  5  /

Type created.

SQL> CREATE TYPE BODY  rectangle_typ  AS
  2    MEMBER FUNCTION  resize( p point_t )  RETURN  rectangle_typ  IS
  3      newrect  rectangle_typ := self;
  4    BEGIN
  5      IF  p.x > self.pt1.x  AND  p.y > self.pt1.y  THEN
  6        newrect.pt2 := p;
  7      END IF;
  8      RETURN  newrect;
  9    END;
 10  END;

Type body created.

SQL> CREATE TABLE  rects1  OF  rectangle_typ (
  2    PRIMARY KEY( pt1.x, pt1.y, pt2.x, pt2.y ) );

Table created.

SQL> INSERT INTO  rects1  VALUES( point_t(1, 2), point_t(3, 4) );

1 row created.

SQL> INSERT INTO  rects1  VALUES( point_t(1, 1), point_t(6, 6) );

1 row created.


SQL> SELECT  r.resize( point_t(10, 10) )  FROM  rects1 r;

R.RESIZE(POINT_T(10,10))(PT1(X, Y), PT2(X, Y))
-----------------------------------------------------------
RECTANGLE_TYP(POINT_T(1, 2), POINT_T(10, 10))
RECTANGLE_TYP(POINT_T(1, 1), POINT_T(10, 10))


SQL> UPDATE  rects1 r
  2    SET  r = r.resize( point_t(r.pt2.x+1, r.pt2.y+1) )
  3    WHERE  r.pt1 = point_t(1, 2);

1 rows updated.