应用场景：
权限管理：同一功能对同一用户有多个不同权限设置（1-允许/0-默认/-1禁用），取组合后的权限值。
--聚合函数就是一个对象
create or replace type permission_sign_object as object (
--对象变量
permission_sign number(1),
--对象初始化
static function ODCIAggregateInitialize(v_self in out permission_sign_object) return number,
--聚合函数的迭代方法
member function ODCIAggregateIterate(self in out permission_sign_object, value in number) return number,
--当查询语句并行运行时,才会使用该方法,可将多个并行运行的查询结果聚合
member function ODCIAggregateMerge(self in out permission_sign_object, v_next in permission_sign_object) return number,
--终止聚集函数的处理,返回聚集函数处理的结果
member function ODCIAggregateTerminate(self in permission_sign_object, return_value out number ,v_flags in number) return number
);
create or replace type body permission_sign_object is
static function ODCIAggregateInitialize(v_self in out permission_sign_object) return number is
begin
v_self := permission_sign_object(0);
return ODCICONST.Success;
end;
member function ODCIAggregateIterate(self in out permission_sign_object, value in number) return number is
begin
if value < 0 then
self.permission_sign := -1;
end if;
if value > 0 then
if self.permission_sign > -1 then
self.permission_sign := 1;
end if;
end if;
return ODCICONST.Success;
end;
member function ODCIAggregateMerge(self in out permission_sign_object, v_next in permission_sign_object) return number is
begin
if v_next.permission_sign < 0 then
self.permission_sign := -1;
end if;
if v_next.permission_sign > 0 then
if self.permission_sign > -1 then
self.permission_sign := 1;
end if;
end if;
return ODCICONST.Success;
end;
member function ODCIAggregateTerminate(self in permission_sign_object, return_value out number ,v_flags in number) return number is
begin
return_value:= self.permission_sign;
return ODCICONST.Success;
end;
end;
create or replace function PermissionSign(value number) return number
parallel_enable aggregate using permission_sign_object;