PL/SQL：带有“where”的方法的成员

Question

我该怎么做：

从三个不同的列中选择值到嵌套表或其他类型的集合中...

DECLARE
TYPE blockers_set IS TABLE OF (
employee_ID NUMBER(8), 
BLOCKING_GROUP NUMBER(4),
BLOCKING_TYPE NUMBER2(2));

select employee_ID, BLOCKING_GROUP, BLOCKING_TYPE 
bulk collect into blockers
from blockers;

...并引用列：

if employee_ID not member of blockers where blocking_group = 1
and blocking_type = 2
then <<business logic>>

blockers-collection 中的一个employee_ID 可以有不止一行。

这必须用 pl/sql 来完成。

Answer 1

你可以这样做：

CREATE TABLE blockers(
                        employee_id NUMBER(8),
                        blocking_group NUMBER(4),
                        blocking_type number(2));


===============================

select * from blockers;

===============================

Create or replace type OBJ_BLOCKERS as OBJECT(
                                                employee_id NUMBER(8),
                                                blocking_group NUMBER(4),
                                                blocking_type number(2)
                                            );

=================================================

Create or replace type varble is table of OBJ_BLOCKERS;

===================================================

DECLARE
  --Creating one element for comparision. In your case you need to populate your employee_id to be compared here.    
  tmp OBJ_BLOCKERS:=OBJ_BLOCKERS(263427,1,2);
  var  varble;
  myid INT;

begin

  --This how you Select values from three different columns into nested table(Object)
  Select OBJ_BLOCKERS(employee_id,
                      blocking_group,
                      blocking_type) 
  Bulk Collect into var
  from blockers;

  -- Displaying Employee_Id from the collection
  For i in 1..var.count
  loop
    dbms_output.put_line(var(i).employee_id);
  end loop;

  --

  SELECT  1
        INTO    myid
        FROM    TABLE(var) q
        where  OBJ_BLOCKERS(q.employee_id,q.blocking_group,q.blocking_type) = tmp --Here you are comparing the employee_id which should be a member of collection
        AND q.blocking_group = 1;

  IF (myid = 1) THEN
       dbms_output.put_line('OK, exists.');
  END IF;       

 Exception
 When No_DATa_found then
        dbms_output.put_line('No Data Found');  

End;                                                    

执行：

SQL> /
263427
534366
454562
OK, exists.

PL/SQL procedure successfully completed.

注意：

如果employee_ID 不是blockers 的成员，其中blocking_group = 1 并且 阻塞类型 = 2

使用Member Funtion 是不可能的。您需要声明一个MAP 方法，该方法相当笨拙，并且如果对象具有很多属性（就像您的情况一样）会变得相当烦人。