oracle study notes (xix) routines - Stored Procedures

Routines - Stored Procedures

We can use the routines to encapsulate what we need action, there are routines stored procedures, functions and triggers.
Here to learn stored procedures -

grammar

create [or replace] procedure $procedure_name$ [(参数列表)]
    is/as --相当于declare
    begin
        [exception]--异常处理
    end $procedure_name$;
    
删除过程：drop procedure $procedure_name$

Create a stored procedure

Create a stored procedure without parameters

create or replace procedure hello
    is
    begin
        dbms_output.put_line('hello world');
    end hello;
    / --执行  

Create a parameterized stored procedure

There are three modes parameter, the parameter type definition without defining a width

mode	Explanation
in (default)	Model parameters may be transmitted in the form of a variable or a literal value
out	Model parameters, must be passed as variables, the variables should not be assigned, the results returned by the receiving process
in out	Model parameters, must be passed as variables

--输出指定字符串（使用in）
create or replace procedure print(text in varchar2)
    is
    begin
        dbms_output.put_line(text);
    end print;
    /
    
--计算结果，返回给调用者（使用out）
create or replace procedure sum(num1 in int,num2 in int,result out int)
    is
    begin
        result := num1 +num2;
    end sum;
/

declare
    --变量不应该赋值
    v_result int := 5;
begin
    sum(5,6,v_result);
    --上面的语句还可以这样写,这样便于直观的知道参数对应哪一个
    --sum(num1 =>5,num2=>6,result=>v_result);
    dbms_output.put_line(v_result);
end;
/

--交换两个数字（使用in out)
create or replace procedure swap(a in out int,b in out int)
is
    v_temp int ;
begin
    v_temp := a;
    a := b;
    b := v_temp;
end swap;
/

declare
    a int :=5;
    b int := 9;
begin
    swap(a,b);
    dbms_output.put_line(a||','||b);
end;
/

carried out

PL / SQL execution

begin
    --包名.过程名
    --未定义包名，不需要写包名
    $procedure_name$;
end;
/

--如果想要其他用户访问当前用户的存储过程,当前用户下，授权给其他用户权限
grant execute on $procedure_name$ to $user_name$;

Command line execution

exec/execute $procedure_name$[(参数)]