oracle存储过程：输入输出

--默认为in
create or replace procedure TestPara(para varchar)
as
begin
  dbms_output.put_line(para);
end;
/
--内部赋值，会报错
create or replace procedure TestPara2(para varchar)
as
begin
  para := '1234';
  dbms_output.put_line(para);
end;
/

create or replace procedure TestInPara(para in varchar)
as
begin
  dbms_output.put_line(para);
end;
/

--输入参数不能赋值
create or replace procedure TestInPara2(para in varchar)
as
begin
  para := '1234';
  dbms_output.put_line(para);
end;
/

create or replace procedure TestOutPara(para out varchar)
as
begin
  dbms_output.put_line(para);
end;
/

--输出内部能够赋值
create or replace procedure TestOutPara2(para out varchar)
as
begin
  para := '1234';
  dbms_output.put_line(para);
end;
/

create or replace procedure TestInOutPara(para in out varchar)
as
begin
  dbms_output.put_line(para);
end;
/

--输出内部能够赋值
create or replace procedure TestInOutPara2(para in out varchar)
as
begin
  para := '1234';
  dbms_output.put_line(para);
end;
/

调用存储过程：

--注意：声明变量必须指定长度
declare
  inpara varchar(100);
begin
  inpara := ' ';
  TestInOutPara2(inpara);
  dbms_output.put_line(inpara);
end;
/