下面对 TEST_FUNCTION 的调用失败，并显示“ORA-03113：通信通道上的文件结尾”。TEST_FUNCTION2 中提供了一种解决方法。我将代码归结为我的实际功能要复杂得多。在 Oracle 11G 上测试。任何人都知道为什么第一个功能会失败？
CREATE OR REPLACE TYPE "EMPLOYEE" AS OBJECT
(
employee_id NUMBER(38),
hire_date DATE
);
CREATE OR REPLACE TYPE "EMPLOYEE_TABLE" AS TABLE OF EMPLOYEE;
CREATE OR REPLACE FUNCTION TEST_FUNCTION RETURN EMPLOYEE_TABLE IS
table1 EMPLOYEE_TABLE;
table2 EMPLOYEE_TABLE;
return_table EMPLOYEE_TABLE;
BEGIN
SELECT CAST(MULTISET
(
SELECT user_id, created FROM all_users
WHERE LOWER(username) < 'm'
) AS EMPLOYEE_TABLE)
INTO table1 FROM dual;
SELECT CAST(MULTISET
(
SELECT user_id, created FROM all_users
WHERE LOWER(username) >= 'm'
) AS EMPLOYEE_TABLE)
INTO table2 FROM dual;
SELECT CAST(MULTISET
(
SELECT employee_id, hire_date
FROM TABLE(table1)
UNION
SELECT employee_id, hire_date
FROM TABLE(table2)
) AS EMPLOYEE_TABLE)
INTO return_table FROM dual;
RETURN return_table;
END TEST_FUNCTION;
CREATE OR REPLACE FUNCTION TEST_FUNCTION2 RETURN EMPLOYEE_TABLE IS
table1 EMPLOYEE_TABLE;
table2 EMPLOYEE_TABLE;
return_table EMPLOYEE_TABLE;
BEGIN
SELECT CAST(MULTISET
(
SELECT user_id, created FROM all_users
WHERE LOWER(username) < 'm'
) AS EMPLOYEE_TABLE)
INTO table1 FROM dual;
SELECT CAST(MULTISET
(
SELECT user_id, created FROM all_users
WHERE LOWER(username) >= 'm'
) AS EMPLOYEE_TABLE)
INTO table2 FROM dual;
WITH combined AS
(
SELECT employee_id, hire_date
FROM TABLE(table1)
UNION
SELECT employee_id, hire_date
FROM TABLE(table2)
)
SELECT CAST(MULTISET
(
SELECT * FROM combined
) AS EMPLOYEE_TABLE)
INTO return_table FROM dual;
RETURN return_table;
END TEST_FUNCTION2;
SELECT * FROM TABLE (TEST_FUNCTION()); -- Throws exception ORA-03113.
SELECT * FROM TABLE (TEST_FUNCTION2()); -- Works