Oracle帶輸入輸出引數的儲存過程
阿新 • • 發佈：2019-01-29
原文連結：http://blog.itpub.net/29485627/viewspace-1248721/
（一）使用輸入引數
需求：在emp_copy中新增一條記錄，empno為已有empno的最大值+1，ename不能為空且長度必須大於0，deptno為60。
建立儲存過程：
create or replace procedure insert_emp(emp_name in varchar2, dept_no in number) as
begin
declare max_empno number;
begin
if(emp_name is null or length(emp_name) = 0) then
return;
end if;
if(dept_no != 60) then
return;
end if;
select max(empno) into max_empno from emp_copy;
insert into emp_copy(empno, ename, deptno) values(max_empno + 1, emp_name, dept_no);
end;
end insert_emp;
/
Procedure created.
呼叫儲存過程並驗證：
(1)
SQL>execute insert_emp('Li Si', 60);
PL/SQL procedure successfully completed.
SQL>
col empno format 99999;
col ename format a15;
col deptno format 99999;
select empno, ename, deptno from emp_copy where deptno = 60;
EMPNO ENAME DEPTNO
------ --------------- ------
7981 Li Si 60
(2)
SQL> execute insert_emp('', 6);
PL/SQL procedure successfully completed.
SQL> select empno, ename, deptno from emp_copy where deptno = 6;
SQL>
（二）使用輸出引數
需求：在上個需求的基礎上，要分別統計表emp_copy插入資料前後的記錄數。
建立儲存過程：
create or replace procedure insert_emp(emp_name in varchar2, dept_no in number, original_count out number, current_count out number) as
begin
declare max_empno number;
begin
if(emp_name is null or length(emp_name) = 0) then
return;
end if;
if(dept_no != 60) then
return;
end if;
select count(1) into original_count from emp_copy;
select max(empno) into max_empno from emp_copy;
insert into emp_copy(empno, ename, deptno) values(max_empno + 1, emp_name, dept_no);
select count(1) into current_count from emp_copy;
end;
end insert_emp;
/
Procedure created.
呼叫儲存過程：
declare count1 number;
count2 number;
begin
insert_emp('Wang Wu', 60, count1, count2);
dbms_output.put_line('Original count of table emp_copy is ' || count1);
dbms_output.put_line('Current count of table emp_copy is ' || count2);
end;
/
Original count of table emp_copy is 15
Current count of table emp_copy is 16
PL/SQL procedure successfully completed.
（三）使用輸入輸出引數
in out引數綜合了上述兩種引數型別，既向過程體傳值，也被賦值而傳到過程體外。in out引數既可以用作輸入也可以用作輸出。
需求:實現兩數交換。
建立儲存過程：
create or replace procedure swap(value1 in out number, value2 in out number) as
begin
value1 := value1 + value2;
value2 := value1 - value2;
value1 := value1 - value2;
end swap;
/
Procedure created.
呼叫儲存過程：
declare a number := 22;
b number := 33;
begin
dbms_output.put_line('Before swap: a = ' || a || ', b = ' || b);
swap(a, b);
dbms_output.put_line('After swap: a = ' || a || ', b = ' || b);
end;
/
Before swap: a = 22, b = 33
After swap: a = 33, b = 22
PL/SQL procedure successfully completed.