需求:
给出如下条件进行批处理编排
- 开始日期时间
- 重复间隔(分钟)
- 重复次数
要求在档期内重复安排节目播出, 比如: 2003.01.01 08:00 开始每隔240分钟播出一次, 一共播出100次

数据库表格(CO_SCHEDULE)
------------------------------
N_PROGIDINT
DT_STARTTIMETIMESTAMP
DT_ENDTIMETIMESTAMP


存储过程的实现：

create table co_schedule(n_progid int,dt_starttime timestamp,dt_endtime timestamp);

//创建函数：
create function add_program_time(int4,timestamp,int4,int4,int4) returns bool as '
declare
prog_id alias for $1;
duration_min alias for $3;
period_min alias for $4;
repeat_times alias for $5;
i int;
starttime timestamp;
ins_starttime timestamp;
ins_endtime timestamp;
begin
starttime :=$2;
i := 0;
while i<repeat_times loop
ins_starttime := starttime;
ins_endtime := timestamp_pl_span(ins_starttime,duration_min ''mins'');
starttime := timestamp_pl_span(ins_starttime,period_min ''mins'');
insert into co_schedule values(prog_id,ins_starttime,ins_endtime);
i := i+1;
end loop;
if i<repeat_times then
return false;
else
return true;
end if;
end;
'language 'plpgsql';

//执行函数：
select add_program_time(1,'2002-10-20 0:0:0','5','60','5');

//查看结果：select * from co_schedule;
n_progid dt_starttime  dt_endtime 
----------+------------------------+------------------------
1 2002-10-20 00:00:00+08 2002-10-20 00:05:00+08
1 2002-10-20 01:00:00+08 2002-10-20 01:05:00+08
1 2002-10-20 02:00:00+08 2002-10-20 02:05:00+08
1 2002-10-20 03:00:00+08 2002-10-20 03:05:00+08
1 2002-10-20 04:00:00+08 2002-10-20 04:05:00+08

ps:
1.数据库一加载 plpgsql语言。如没有，
su - postgres
createlang plpgsql dbname
2.至于返回类型为bool,是因为我不知道如何让函数不返回值。等待改进。