Another motivational example for inverse view

table PolarCoordinates (

    theta real,
    R real,
)

with constraints R>0, 0<=theta<pi

view CartesianCoordinates
select R*cos(theta) AS x, R*sin(theta) AS y from PolarCoordinates

This view is clearly updateable, all we need to do is to apply inverse mapping to the any tuple inserted/updated/deleted.

We can even write inverse view explicitly:

view PolarCoordinates
select sqrt(x*x+y*y) AS R, arcsin(y/sqrt(x*x+y*y)) as theta from PolarCoordinates Received on Wed Nov 15 2006 - 02:30:54 CET