有人对系统为什么告诉我PAR_CUR已经打开有任何想法吗？一切正常，直到我添加了最外面的光标（dup_cur），现在我收到了这个错误。感谢您提供的任何帮助。数据也在下面。
错误报告：
ORA-06511: PL/SQL: cursor already open
ORA-06512: at line 18
ORA-06512: at line 61
06511. 00000 - "PL/SQL: cursor already open"
*Cause: An attempt was made to open a cursor that was already open.
*Action: Close cursor first before reopening.
代码：
ACCEPT p_1 prompt 'PLEASE ENTER THE REGION:'
DECLARE
v_child regions.child_name%TYPE := '&p_1';
v_parent regions.parent_name%TYPE;
v_parent2 regions.child_name%TYPE;
v_parent3 regions.child_name%TYPE;
v_count NUMBER := 0;
v_regionnumber NUMBER := 1;
v_parentcount NUMBER := 0;
v_dup regions.child_name%TYPE;
CURSOR reg_cur IS
SELECT Upper(parent_name)
FROM regions
WHERE Upper(child_name) = Upper(v_child)
AND Upper(parent_name) = Upper(v_dup);
CURSOR par_cur IS
SELECT Upper(parent_name)
FROM regions
WHERE Upper(child_name) = v_parent
AND parent_name IS NOT NULL;
CURSOR dup_cur IS
SELECT Upper(parent_name)
FROM regions
WHERE Upper(child_name) = Upper(v_child);
开始打开 dup_cur;
LOOP
FETCH dup_cur INTO v_dup;
EXIT WHEN dup_cur%NOTFOUND;
SELECT Count(*)
INTO v_count
FROM regions
WHERE Upper(child_name) = Upper(v_child);
SELECT Count(parent_name)
INTO v_parentcount
FROM regions
WHERE Upper(parent_name) = Upper(v_child);
IF v_count > 0
OR v_parentcount > 0 THEN
SELECT Count(parent_name)
INTO v_count
FROM regions
WHERE Upper(child_name) = Upper(v_child);
IF v_count > 0 THEN
OPEN reg_cur;
FETCH reg_cur INTO v_parent;
dbms_output.Put_line('----- Begin Output -----');
LOOP
IF v_regionnumber < 2 THEN
dbms_output.Put_line('Line 1: (Region 1) '
|| Upper(v_child));
dbms_output.Put_line('Line 2: (Region 1) '
|| Upper(v_child)
|| ' --> '
|| '(Region 2) '
|| Upper (v_parent));
END IF;
OPEN par_cur;
v_parent2 := v_parent;
FETCH par_cur INTO v_parent;
EXIT WHEN par_cur%NOTFOUND;
v_regionnumber := v_regionnumber + 1;
IF v_regionnumber = 2 THEN
dbms_output.Put_line('Line 3: '
|| '(Region 1) '
|| Upper(v_child)
|| ' --> '
|| '(Region 2) '
|| Upper(v_parent2)
|| ' --> '
|| '(Region 3) '
|| Upper(v_parent));
ELSE
IF v_regionnumber = 3 THEN
dbms_output.Put_line('Line 4: '
|| '(Region 1) '
|| Upper(v_child)
|| ' --> '
|| '(Region 2) '
|| Upper(v_parent3)
|| ' --> '
|| '(Region 3) '
|| Upper(v_parent2)
|| ' --> '
|| '(Region 4) '
|| Upper(v_parent));
END IF;
END IF;
CLOSE par_cur;
v_parent3 := v_parent2;
END LOOP;
dbms_output.Put_line('----- End_Output -----');
CLOSE reg_cur;
ELSE
dbms_output.Put_line('----- Begin Output -----'
|| Chr(10)
|| 'Line 1: (Region 1) '
|| Upper(v_child)
|| Chr(10)
|| '----- End_Output -----');
END IF;
ELSE
dbms_output.Put_line('----- Begin Output -----'
|| Chr(10)
|| Upper(v_child)
||' is not in the table.'
|| Chr(10)
|| '----- End_Output -----');
END IF;
END LOOP;
CLOSE dup_cur;
END;
CREATE TABLE regions
(
PARENT_NAME VARCHAR2(30),
CHILD_NAME VARCHAR2(30)
);
INSERT INTO regions VALUES('Texas','Rockford');
INSERT INTO regions VALUES('Colorado','Aurora');
INSERT INTO regions VALUES(NULL,'Asia');
INSERT INTO regions VALUES(NULL,'Australia');
INSERT INTO regions VALUES(NULL,'Europe');
INSERT INTO regions VALUES(NULL,'North America');
INSERT INTO regions VALUES('Asia','China');
INSERT INTO regions VALUES('Asia','Japan');
INSERT INTO regions VALUES('Australia','New South Wales');
INSERT INTO regions VALUES('New South Wales','Sydney');
INSERT INTO regions VALUES('Canada','Ontario');
INSERT INTO regions VALUES('China','Beijing');
INSERT INTO regions VALUES('England','London');
INSERT INTO regions VALUES('Europe','United Kingdom');
INSERT INTO regions VALUES('Illinois','Aurora');
INSERT INTO regions VALUES('Illinois','Chicago');
INSERT INTO regions VALUES('Illinois','Rockford');
INSERT INTO regions VALUES('Wisconsin','Madison');
INSERT INTO regions VALUES('Japan','Osaka');
INSERT INTO regions VALUES('Japan','Tokyo');
INSERT INTO regions VALUES('North America','Canada');
INSERT INTO regions VALUES('North America','United States');
INSERT INTO regions VALUES('Ontario','Ottawa');
INSERT INTO regions VALUES('Ontario','Toronto');
INSERT INTO regions VALUES('United States','Colorado');
INSERT INTO regions VALUES('United States','Illinois');
INSERT INTO regions VALUES('United States','Texas');
INSERT INTO regions VALUES('United Kingdom','England');
COMMIT;