oracle中的function,procedure,package.
create sequence seq_loginfo;
create table loginfo
(
  id number primary key,
  logName varchar(20) not null,
  logPass varchar(20) not null
);
--drop TABLE loginfo;
insert into loginfo(id, logname, logpass) values (seq_loginfo.nextval,'admin','123');    
select * from loginfo;
create or replace function validLogin(loginName_ varchar2,
                                      loginPwd_  varchar2) return number is
  cursor login_ is
    select * from loginfo t where t.logname = loginName_;
  r login_%Rowtype;
begin
  open login_;
  fetch login_
    into r;
  close login_;
  if (r.logPass is not null) then
    if (r.logPass = loginPwd_) then
      return 1;
    else
      return 0;
    end if;
  else
    return 0;
  end if;
end;
declare
  returnNumber_ number;
begin
  returnNumber_ := validLogin('admin', '123');
  dbms_output.put_line('returnNumber_ :=' || returnNumber_);
end;
create or replace procedure login_proc(
  loginname_ in loginfo.logname%type,
  loginpwd_  in loginfo.logpass%type,
  returnMsg_ in out varchar2) is
  cursor login_ is select * from loginfo t where t.logname=loginname_;
  r login_%Rowtype;
  begin
    open login_;
    fetch login_ into r;
    close login_;
    if(r.logPass is not null) then
       if(r.logPass = loginpwd_ )then
             returnMsg_:='登录成功';
        else
             returnMsg_:='密码错误'; 
        end if;
     else
       returnMsg_:='用户名有误';
    end if;
end; 
declare
  returnMsg_ varchar2(200);
begin
  login_proc('admin', '123', returnMsg_);
  dbms_output.put_line('returnMsg_ :=' || returnMsg_);
end;

create or replace package Login__ is
   function validLogin(loginName_ varchar2,
                                        loginPwd_ varchar2) return number;
   procedure login_proc(loginname_ in
                                         loginfo.logname%type,
                                         loginpwd_ in loginfo.logpass%type,
                                         returnMsg_ in out varchar2);