SDO_GEOM.SDO_AREA() function - sql

Question

I have this trouble
declare
cursor tab is
select symbol, SDO_GEOM.SDO_AREA(geom, 0.1)
from budynki2
order by 2 desc;
begin
for x in tab loop
dbms_output.put_line(x.symbol || ' ' ||x.geom);
end loop;
end;
Still I get a error that PLS-00302: component 'GEOM' must be declared
I don't know how I can get in to values of second's column in my curosor.
;((

Answer 1

Try to use
declare
cursor tab is
select symbol, SDO_GEOM.SDO_AREA(b.geom, 0.1)
from budynki2 b
order by 2 desc;
begin
for x in tab loop
dbms_output.put_line(x.symbol || ' ' ||x.geom);
end loop;
end;
by aliasing your table budynki2 as b, and prefix your column geom with this alias as b.geom. Assuming you have a column named geom in your table of type SDO_GEOMETRY, you may have another object, in your schema, whose name is geom, and that ambigious definition causes this error.

Answer 2

Still I get a error that PLS-00302: component 'GEOM' must be declared
In your cusor there is no column name GEOM (column still present in table but cursor not able to identify) and that is what Oracle reporting. You just need to alias your SDO_GEOM.SDO_AREA as GEOM and rest should work.
DECLARE
CURSOR TAB
IS
SELECT SYMBOL,
SDO_GEOM.SDO_AREA (GEOM, 0.1) AS GEOM
FROM BUDYNKI2
ORDER BY 2 DESC;
BEGIN
FOR X IN TAB
LOOP
DBMS_OUTPUT.PUT_LINE (X.SYMBOL || ' ' || X.GEOM);
END LOOP;
END;
See Demo:
Table:
SQL> CREATE TABLE cola_markets (
2 mkt_id NUMBER PRIMARY KEY,
3 name VARCHAR2(32),
4 shape SDO_GEOMETRY);
Table created.
SQL> INSERT INTO cola_markets VALUES(
2 1,
3 'cola_a',
4 SDO_GEOMETRY(
5 2003,
6 NULL,
7 NULL,
8 SDO_ELEM_INFO_ARRAY(1,1003,3),
9 SDO_ORDINATE_ARRAY(1,1, 5,7)
10 )
11 );
1 row created.
SQL> INSERT INTO cola_markets VALUES(
2 2,
3 'cola_b',
4 SDO_GEOMETRY(
5 2003,
6 NULL,
7 NULL,
8 SDO_ELEM_INFO_ARRAY(1,1003,1),
9 SDO_ORDINATE_ARRAY(5,1, 8,1, 8,6, 5,7, 5,1)
10 )
11 );
1 row created.
SQL> INSERT INTO cola_markets VALUES(
2 3,
3 'cola_c',
4 SDO_GEOMETRY(
5 2003,
6 NULL,
7 NULL,
8 SDO_ELEM_INFO_ARRAY(1,1003,1),
9 SDO_ORDINATE_ARRAY(3,3, 6,3, 6,5, 4,5, 3,3)
10 )
11 );
1 row created.
SQL> commit;
Block:
Error Simulation:
You need to note that even though my table has column named SHAPE, when i used it in for loop , it produced error. Same as your case.
SQL> DECLARE
2 CURSOR TAB
3 IS
4 SELECT name, SDO_GEOM.SDO_AREA(shape, 0.005)
5 FROM cola_markets
6 ORDER BY 2 DESC;
7 BEGIN
8 FOR X IN TAB
9 LOOP
10 DBMS_OUTPUT.PUT_LINE (X.NAME || ' ' || X.shape);
11 END LOOP;
12 END;
13 /
DBMS_OUTPUT.PUT_LINE (X.NAME || ' ' || X.shape);
*
ERROR at line 10:
ORA-06550: line 10, column 52:
PLS-00302: component 'SHAPE' must be declared
ORA-06550: line 10, column 11:
PL/SQL: Statement ignored
Remedy
SQL> DECLARE
2 CURSOR TAB
3 IS
4 SELECT name,
SDO_GEOM.SDO_AREA(shape, 0.005) AS GEOM --<-Alised the column and problem is resolved
5 FROM cola_markets
6 ORDER BY 2 DESC;
7 BEGIN
8 FOR X IN TAB
9 LOOP
10 DBMS_OUTPUT.PUT_LINE (X.NAME || ' ' || X.GEOM);
11 END LOOP;
12 END;
13 /
cola_a 24
cola_b 16.5
cola_c 5
PL/SQL procedure successfully completed.