thnx for your response
actualy what I am traying to do is simulate a person walking
here is my code
counter INTEGER := 1 ;
(just example for updating position 5 times)
( this to get the next position along the road (chemin column))
update person as t1 set position_geom=
( SELECT ST_Line_Interpolate_Point (chemin,
(counter *(select ST_Length(chemin:: geography) ))) from person as t2,
where t1.id=t2.id );
WAITFOR DELAY '00:00:10';
counter := counter + 1 ;
END LOOP ;
the column position is updating every 10s. now when i try to get this new value (with select query ) befor the loop is finished I get always the same value which is the old value befor the loop start.
I guess the loop lock this column ,so I can't get the new value untill the loop is finish .
any idea to resolve that or other issue to simulate man walking .