如何在PL / SQL中使用动态插入并检查游标下的循环？

Question

create or replace package IR is
procedure chkval;
end IR;

create or replace package body IR is
procedure chkval is
lheat IR_SENSE.heat%type;
cursor cur is select heat from IR_SENSE;
begin
open cur;
loop
insert into IR_SENSE values(to_number(substr(dbms_random.random,1,4)));
fetch cur into lheat;
dbms_output.put_line(lheat);
commit;
exit when lheat>4000;
exit when cur%notfound;
end loop;
close cur;
end;
end IR`enter code here`

在这里，我试图在表中执行动态插入（值是作为温度从红外传感器发出的），并且如果值超过阈值，则需要发出警报（退出程序）。

Answer 1

这是一个选择； 我没有写程序包（也没有存储过程）-这是一个匿名的PL / SQL块，您可以轻松地将其重写为所需的任何内容。

创建测试用例：

SQL> create table ir_sense (heat number);

Table created.

SQL> insert into ir_sense (heat)
  2  select round(dbms_random.value * 7500)
  3  from dual
  4  connect by level <= 1000;

1000 rows created.

SQL>

代码及其输出：

SQL> set serveroutput on
SQL>
SQL> declare
  2    l_treshold number := 8000;
  3    l_cnt      number := 0; -- number of values lower than L_TRESHOLD
  4  begin
  5    for cur_r in (select heat from ir_sense
  6                  order by heat  -- so that I wouldn't exit too fast
  7                 )
  8    loop
  9      l_cnt := l_cnt + 1;
 10      if cur_r.heat > 4000 then
 11         dbms_output.put_line('Treshold reached after ' || l_cnt || ' readings');
 12         exit;
 13      end if;
 14    end loop;
 15  end;
 16  /
Treshold reached after 525 readings

PL/SQL procedure successfully completed.

SQL>

[编辑：一种新方法]

如果值小于4000，则P_SENSE过程将插入值，然后将“ N”作为“ PAR_STOP”参数返回（即“不停止加载”）； 否则，返回“ Y”。

SQL> create table ir_sense (heat number);

Table created.

SQL> create or replace procedure p_sense (par_heat in number, par_stop out varchar2) is
  2  begin
  3    if par_heat > 4000 then
  4       -- stop loading
  5       par_stop := 'Y';
  6    else
  7       insert into ir_sense(heat) values (par_heat);
  8       par_stop := 'N';
  9    end if;
 10  end;
 11  /

Procedure created.

测试：WHILE循环模拟您从设备接收的值，并一直执行该操作，直到P_SENSE过程返回PAR_STOP = Y（即停止加载）。

SQL> declare
  2    l_heat number;
  3    l_stop varchar2(1) := 'N';
  4  begin
  5    -- simulating temperature readings
  6    while l_stop = 'N' loop
  7      l_heat := round(dbms_random.value * 7500);
  8      p_sense(l_heat, l_stop);
  9    end loop;
 10  end;
 11  /

PL/SQL procedure successfully completed.

SQL> select count(*) from ir_sense;

  COUNT(*)
----------
         3

SQL> select * from ir_sense;

      HEAT
----------
       187
      2328
      1072