ORACLE PL/SQL函數創建成功，但執行體工作不

Question

這是我創建的表的列表並插入值作爲創建的表：

CREATE TABLE DEPARTMENT 
(DEPARTMENT_ID NUMBER PRIMARY KEY, 
DEPARTMENT_NAME VARCHAR(30) NOT NULL 
); 

CREATE TABLE JOBS 
(JOB_ID NUMBER PRIMARY KEY, 
    JOB_TITLE VARCHAR(35) NOT NULL, 
    MIN_SALARY DECIMAL NOT NULL, 
    MAX_SALARY DECIMAL NOT NULL 
); 

CREATE TABLE EMPLOYEES 
(EMPLOYEE_ID NUMBER PRIMARY KEY, 
FIRST_NAME VARCHAR(20) NOT NULL, 
LAST_NAME VARCHAR(25) NOT NULL, 
EMAIL VARCHAR(25) NOT NULL, 
PHONE_NUMBER VARCHAR(20) NOT NULL, 
HIRE_DATE DATE NOT NULL, 
JOB_ID NUMBER NOT NULL, 
SALARY DECIMAL NOT NULL, 
DEPARTMENT_ID NUMBER NOT NULL, 
CONSTRAINT emp_job_fk FOREIGN KEY(JOB_ID) REFERENCES JOBS(JOB_ID), 
CONSTRAINT emp_department_fk FOREIGN KEY(DEPARTMENT_ID) REFERENCES DEPARTMENT(DEPARTMENT_ID) 
); 

INSERT INTO DEPARTMENT (DEPARTMENT_ID,DEPARTMENT_NAME) 
VALUES(1,'IT'); 
INSERT INTO DEPARTMENT (DEPARTMENT_ID,DEPARTMENT_NAME) 
VALUES(2,'Sales'); 

INSERT INTO JOBS (JOB_ID,JOB_TITLE,MIN_SALARY,MAX_SALARY) 
VALUES (1,'IT Administrator',250000.00,50000.00); 
INSERT INTO JOBS (JOB_ID,JOB_TITLE,MIN_SALARY,MAX_SALARY) 
VALUES (2,'Salesman',200000.00,40000.00); 

INSERT INTO EMPLOYEES (EMPLOYEE_ID,FIRST_NAME,LAST_NAME,EMAIL,PHONE_NUMBER,HIRE_DATE,JOB_ID,SALARY,DEPARTMENT_ID) 
VALUES (1,'Tony','Starc','starc@gmail.com','',TO_DATE('15/1/2008','DD/MM/YYYY'),1,45000.00,1); 
INSERT INTO EMPLOYEES (EMPLOYEE_ID,FIRST_NAME,LAST_NAME,EMAIL,PHONE_NUMBER,HIRE_DATE,JOB_ID,SALARY,DEPARTMENT_ID) 
VALUES (2,'Bruce','Wayne','bruce@gmail.com','',TO_DATE('15/1/2009','DD/MM/YYYY'),1,40000.00,1); 
INSERT INTO EMPLOYEES (EMPLOYEE_ID,FIRST_NAME,LAST_NAME,EMAIL,PHONE_NUMBER,HIRE_DATE,JOB_ID,SALARY,DEPARTMENT_ID) 
VALUES (3,'Larry','Ellison','larry@gmail.com','',TO_DATE('15/1/2010','DD/MM/YYYY'),1,30000.00,1); 
INSERT INTO EMPLOYEES (EMPLOYEE_ID,FIRST_NAME,LAST_NAME,EMAIL,PHONE_NUMBER,HIRE_DATE,JOB_ID,SALARY,DEPARTMENT_ID) 
VALUES (4,'Steve','Jobs','steve@gmail.com','',TO_DATE('15/1/2011','DD/MM/YYYY'),2,35000.00,2); 
INSERT INTO EMPLOYEES (EMPLOYEE_ID,FIRST_NAME,LAST_NAME,EMAIL,PHONE_NUMBER,HIRE_DATE,JOB_ID,SALARY,DEPARTMENT_ID) 
VALUES (5,'Remy','Lebeau','remy@gmail.com','',TO_DATE('15/1/2012','DD/MM/YYYY'),2,30000.00,2); 
INSERT INTO EMPLOYEES (EMPLOYEE_ID,FIRST_NAME,LAST_NAME,EMAIL,PHONE_NUMBER,HIRE_DATE,JOB_ID,SALARY,DEPARTMENT_ID) 
VALUES (6,'Clark','Kent','clark@gmail.com','',TO_DATE('15/1/2013','DD/MM/YYYY'),2,35000.00,2); 

現在在我的分配問題，我有被要求解決以下問題： 編寫一個名爲fn_emps_per_dept_jc450912的函數以檢索具有給定DEPARTMENT_ID的EMPLOYEE_ID，FIRST_NAME，LAST_NAME和JOB_TITLE。此函數應將DEPARTMENT_ID作爲輸入參數，此函數應具有EMPLOYEE_ID，FIRST_NAME，LAST_NAME和JOB_TITLE作爲輸出參數。它應該返回TRUE，如果找到則返回FALSE。

爲了從一個特定部門顯示員工的信息，我寫了下面的功能：

CREATE OR REPLACE FUNCTION fn_emps_per_dept_jc450912 (f_dept_id IN NUMBER,f_emp_id OUT NUMBER,f_first_name OUT VARCHAR,f_last_name OUT VARCHAR,f_job_title OUT VARCHAR) 
RETURN BOOLEAN 
AS 
BEGIN 
SELECT EMPLOYEE_ID,FIRST_NAME,LAST_NAME,JOB_TITLE 
INTO f_emp_id,f_first_name,f_last_name,f_job_title 
FROM EMPLOYEES,JOBS,DEPARTMENT 
WHERE DEPARTMENT.DEPARTMENT_ID = EMPLOYEES.DEPARTMENT_ID 
AND JOBS.JOB_ID = EMPLOYEES.JOB_ID 
AND EMPLOYEES.DEPARTMENT_ID = f_dept_id; 
RETURN TRUE; 
EXCEPTION 
WHEN NO_DATA_FOUND 
THEN 
DBMS_OUTPUT.PUT_LINE('Employee not found'); 
RETURN FALSE; 
END fn_emps_per_dept_jc450912; 

Function FN_EMPS_PER_DEPT_JC450912 compiled 

，該功能已成功編譯正如你可以從上面看到的。

然後我試圖執行的功能：

DECLARE 
f_dept_id NUMBER; 
f_emp_id NUMBER; 
f_first_name VARCHAR(30) ; 
f_last_name VARCHAR(30) ; 
f_job_title VARCHAR(30); 
f_return BOOLEAN; 
BEGIN 
f_dept_id := 1; 
f_return := fn_emps_per_dept_jc450912(f_dept_id,f_emp_id,f_first_name,f_last_name,f_job_title); 
DBMS_OUTPUT.PUT_LINE('Employee_ID: ' || f_emp_id); 
DBMS_OUTPUT.PUT_LINE('First Name: ' || f_first_name); 
DBMS_OUTPUT.PUT_LINE('Last Name: ' || f_last_name); 
DBMS_OUTPUT.PUT_LINE('Job: ' || f_job_title); 
END; 

，我發現了以下錯誤：

Error report - 
ORA-01422: exact fetch returns more than requested number of rows 
ORA-06512: at "SYSTEM.FN_EMPS_PER_DEPT_JC450912", line 5 
ORA-06512: at line 10 
01422. 00000 - "exact fetch returns more than requested number of rows" 
*Cause: The number specified in exact fetch is less than the rows returned. 
*Action: Rewrite the query or change number of rows requested 

我需要的解決方案代號爲執行主體來修復這個錯誤。

Answer 1

首先請使用現代連接語法（從92開始的ANSI標準！）。

所以，你的選擇應該是：

SELECT EMPLOYEE_ID,FIRST_NAME,LAST_NAME,JOB_TITLE 
INTO f_emp_id,f_first_name,f_last_name,f_job_title 
FROM EMPLOYEES INNER JOIN JOBS ON JOBS.JOB_ID = EMPLOYEES.JOB_ID 
INNER JOIN DEPARTMENT ON DEPARTMENT.DEPARTMENT_ID = EMPLOYEES.DEPARTMENT_ID 
WHERE EMPLOYEES.DEPARTMENT_ID = f_dept_id; 

下，當你得到這樣的問題，你應該只運行查詢的查詢窗口，如下：

SELECT EMPLOYEE_ID,FIRST_NAME,LAST_NAME,JOB_TITLE 
FROM EMPLOYEES INNER JOIN JOBS ON JOBS.JOB_ID = EMPLOYEES.JOB_ID 
INNER JOIN DEPARTMENT ON DEPARTMENT.DEPARTMENT_ID = EMPLOYEES.DEPARTMENT_ID 
WHERE EMPLOYEES.DEPARTMENT_ID = 1; 

這將揭示你的問題的原因，因爲輸出看起來像這樣

EMPLOYEE_ID FIRST_NAME   LAST_NAME     JOB_TITLE       
----------- -------------------- ------------------------- ----------------------------------- 
      1 Tony     Starc      IT Administrator     
      2 Bruce    Wayne      IT Administrator     
      3 Larry    Ellison     IT Administrator     

即，該領域employees.departme nt_id不是唯一的。因此在執行時，存儲過程試圖將多個值放入一個變量中。這是它不能做的，因此錯誤。該過程編譯好，因爲在編譯時，過程不知道它會傳遞一個參數，這會導致結果集中有多個記錄。