我正在为我们运行的网站编写一个成就模块。这段代码将在给定的时间范围结束时在SQL Server上运行,以奖励成果(下次访问该网站时将通过客户端通知)。如何替换嵌套游标?
所以我需要看看所有的团队和所有的“最终”成就(这是独立的团队)。每项成就都有一个或多个必须符合的规则。一旦我确定成绩通过了,我就会将该成就奖给该团队的所有参与者。
我是通过游标处理这一点,我得到了一个错误,所以当我去谷歌问题,我上的论坛上无休止的链接“你傻乎乎$ &#$为什么你使用游标”(意译) 。我想,当我解决我的问题的时候,我可能会更换我使用的基于集合的方法(如果可能的话)。
我发现的另一个例子是所有基本的更新场景,在表格上使用单个嵌套循环来实现相互之间的密钥交互,老实说,我不会考虑在这些场景中使用游标来开始。
我下面的内容是而不是完全在句法上是正确的,但我可以通过玩弄自己来解决这个问题。这应该给的什么,我试图完成一个清晰的思路,但是:
declare @TimeframeID int;
declare @AchievementID int;
declare @q1 int;
declare @q2 int;
declare @TeamID int;
declare @TotalReg int;
declare @TotalMin int;
declare @AvgMin decimal(10, 2);
declare @AggType varchar(50);
declare @Pass bit = 1;
declare @Email varchar(50);
declare @ParticipantID int;
select @TimeframeID = MAX(TimeframeID) from Timeframes
where IsActive = 1;
declare team_cur CURSOR FOR
select
t.TeamID,
(select COUNT(1) from Registrations r
where r.TeamID = t.TeamID and r.TimeframeID = @TimeframeID) TotalReg,
(select SUM(Minutes) from Activities a
inner join Registrations r on r.RegistrationID = a.RegistrationID
where r.TeamID = t.TeamID and r.TimeframeID = @TimeframeID) TotalMin
from Teams t
where Active = 1
group by TeamID;
declare ach_cur CURSOR FOR
select AchievementID from luAchievements
where TimeframeID = @TimeframeID and AchievementType = 'End';
declare rule_cur CURSOR for
select Quantity1, Quantity2, AggregateType
from AchievementRule_Links arl
inner join luAchievementRules ar on ar.RuleID = arl.RuleID
where arl.AchievementID = @AchievementID;
open team_cur;
fetch next from team_cur
into @TeamID, @TotalReg, @TotalMin;
while @@FETCH_STATUS = 0
begin
open ach_cur;
fetch next from ach_cur
into @AchievementID;
while @@FETCH_STATUS = 0
begin
open rule_cur;
fetch next from rule_cur
into @q1, @q2, @AggType;
while @@FETCH_STATUS = 0
begin
if @AggType = 'Total'
begin
if @q1 > @TotalReg
begin
set @Pass = 0;
end
end
else if @AggType = 'Average'
begin
print 'do this later; need to get specs';
end
fetch next from rule_cur
into @q1, @q2, @AggType;
end
close rule_cur;
deallocate rule_cur;
-- if passed, award achievement to all team members
if @Pass = 1
begin
declare reg_cursor cursor for
select max(p.Email) from Participants p
inner join Registrations reg on reg.ParticipantID = p.ParticipantID
where reg.TeamID = @TeamID;
open reg_cursor;
fetch next from reg_cursor
into @Email;
while @@FETCH_STATUS = 0
begin
exec ProcessAchievement @AchievementID, @Email, 0;
fetch next from reg_cursor
into @Email;
end
close reg_cursor;
deallocate reg_cursor;
-- award achievement to team
exec ProcessTeamAchievement @AchievementID, @TeamID;
end
fetch next from ach_cur
into @AchievementID;
end
close ach_cur;
deallocate ach_cur;
fetch next from team_cur
into @TeamID, @TotalReg, @TotalMin;
end
close team_cur;
deallocate team_cur;
是否有一个基于集合的替代我在这里做什么?我需要补充的是,这是针对一小部分记录运行的,所以表现并不是我关心的问题;未来庞大更新的最佳实践。
感谢您的帮助!当然,这是一种更有效和正确的做事方式。 – Ryan