我写了一个程序，我可以在那里申请身份证。
有不同类型的身份证（红色，蓝色，绿色）
在请求时，程序应生成标识号。数字（数字的范围）取决于所请求的卡。
Red Card: 1 - 50000
Blue Card: 50001 - 100000
Green Card: 100001 - 150000
如果我向系统添加新的身份证，那么序列应自动为新添加的身份证创建新的数字范围。数字不应再发生。一个号码只能使用一次。
我该怎么做？任何人都可以帮我吗？
答案 0 :(得分：2)
您可以使用而不是插入触发器来实现此
create table Cards_Types (Color nvarchar(128) primary key, Start int);
create table Cards (ID int primary key, Color nvarchar(128));
insert into Cards_Types
select 'RED', 0 union all
select 'BLUE', 50000 union all
select 'GREEN', 100000;
create trigger utr_Cards_Insert on Cards
instead of insert as
begin
insert into Cards (id, Color)
select
isnull(C.id, CT.Start) + row_number() over(partition by i.Color order by i.id),
i.Color
from inserted as i
left outer join Cards_Types as CT on CT.Color = i.Color
outer apply (
select max(id) as id
from Cards as C
where C.Color = i.Color
) as C
end
<强> sql fiddle demo
它允许您一次插入多行：
insert into Cards (Color)
select 'GREEN' union all
select 'GREEN' union all
select 'RED' union all
select 'BLUE'
请注意，您最好在卡片列Color, ID上设置索引。
另请注意，您可以为每种类型仅插入50000条记录。您可以使用不同的种子，例如1种用于“红色”，2种用于“蓝色”种子。依此类推，并保留例如100张类型卡片的地方：
create table Cards_Types (Color nvarchar(128) primary key, Start int);
create table Cards (ID int primary key, Color nvarchar(128));
insert into Cards_Types
select 'RED', 1 union all
select 'BLUE', 2 union all
select 'GREEN', 3;
create trigger utr_Cards_Insert on Cards
instead of insert as
begin
insert into Cards (id, Color)
select
isnull(C.id, CT.Start - 100) + row_number() over(partition by i.Color order by i.id) * 100,
i.Color
from inserted as i
left outer join Cards_Types as CT on CT.Color = i.Color
outer apply (
select max(id) as id
from Cards as C
where C.Color = i.Color
) as C
end;
<强> sql fiddle demo
以这种方式识别＆＃39; RED＆＃39;将始终以1结尾，ID为＆＃39; BLUE＆＃39;结束于2，依此类推。
答案 1 :(得分：2)
从设计角度来看，我强烈反对将附加逻辑编码为标识符，即将卡颜色分配给特定范围。我宁愿使用IDENTITY列来处理唯一性和并发性，使ID完全代理并在另一个属性中存储给定ID的卡颜色信息。可能在该附加属性上创建索引以检索给定颜色的记录。
还要考虑一下，如果红卡的所有者要求将其改为蓝色的那个，会有什么需要？使用范围，要保留颜色分配，您需要创建一个新的ID，并可能在其他地方存储有关从旧到新的id序列的信息。如果有人多次更改怎么办？使用代理ID，您可以随时拥有一个ID，以便能够在整个历史记录中跟踪同一个人，也许只需在表中添加日期信息即可按顺序进行更改。这只是一个简单场景的例子。
答案 2 :(得分：1)
您可以利用SQL Server的IDENTITY机制，因为它易于使用并且可以很好地处理并发性。
更具体地说，您可以使用以下脚本创建三个仅包含标识（自动递增）Id列的表：
create table RedCardIds(Id int identity(1, 1) primary key)
create table BlueCardIds(Id int identity(50001, 1) primary key)
create table GreenCardIds(Id int identity(100001, 1) primary key)
GO
这三个表的标识值设置为与您的间隔下限匹配。
然后，对于每个请求，您都要插入相应的表并使用the OUTPUT clause来获取新生成的标识值。
例如，如果请求是红牌，您可以写：
insert RedCardIds
output inserted.Id
default values
将输出：
Id
-----------
1
(1 row(s) affected)
在下次运行时，它将返回2，依此类推。
同样，第一张蓝卡请求会触发声明：
insert BlueCardIds
output inserted.Id
default values
结果：
Id
-----------
500001
(1 row(s) affected)
答案 3 :(得分：0)
理想情况下，您必须维护一个表来存储此信息。
CardCategry MinNumber MaxNumber RunningNumber
然后您可以编写SP以获取下一个号码并将卡类别作为参数传递。示例查询如下。
SELECT @count=count(RunningNumber)
FROM IdentificationTable
WHERE CardCategry=@param
IF (@count=1)
SELECT @RunningNumber=RunningNumber
FROM IdentificationTable
WHERE CardCategry=@param
ELSE
SELECT TOP 1 @min=MinNumber,@max=MaxNumber
FROM IdentificationTable
ORDER BY MinNumber DESC
INSERT INTO IdentificationTable VALUES (@param,@max+1,@max+(@max-@min),1)
SET @RunningNumber=1
RETURN @RunningNumber
这不是一项完整的工作。显然，您必须对检查边界限制等进行一些错误处理。
答案 4 :(得分：0)
我会尝试这样的事情：
declare @cat2start int = 50000
declare @cat3start int = 100000
declare @catName varchar(10) = 'Red'
if @catName = 'Green'
begin
select (max(cardnumber) + 1) as [This is the next number]
from yourTable
where
cardnumber < @cat2start
end
if @catName = 'Blue'
begin
select (max(cardnumber) + 1) as [This is the next number]
from yourTable
where
cardumber >= @cat2start and cardnumber < @cat3start
end
if @catName = 'Red'
begin
select (max(cardnumber) + 1) as [This is the next number]
from yourTable
end
答案 5 :(得分：0)
有很多答案，但我会加2美分。请注意，我假设我在对原始帖子的评论中所写的内容：
create table cardTypes(cardTypeName varchar(100) primary key, [50kSlot] int unique)
create table cards (identificationNumber bigint primary key);
--add slot if needed
declare @cardToBeAdded varchar(100) = 'green'
declare @tbl50kSlot table (i int)
merge into cardTypes as t
using (select @cardToBeAdded as newCard) as s
on t.[cardTypeName] = s.newCard
when not matched by target then
insert (cardTypeName, [50kSlot]) values (s.newCard, isnull((select max([50kSlot]) + 1 from cardTypes),1))
when matched then
update set [50kSlot] = [50kSlot]
output inserted.[50kSlot] into @tbl50kSlot;
declare @50kSlot int = (Select i from @tbl50kSlot)
insert into cards (identificationNumber) values (isnull(
(select max(identificationNumber)+1 from cards where identificationNumber between ((@50kSlot-1)*50000+1) and @50kSlot*50000),
(@50kSlot-1)*50000+1)
)
当然，您需要将一些实际数据添加到卡表中。请注意，如果存在足够有效的索引，则可以相对快速地执行最后一个查询。如果存在性能问题，可能需要解决标识号的索引问题。考虑 - 例如 - 如果您有很多行，则在此列上创建过滤索引。
或者，您可以将maxInt保留在cardTypes表中，并使合并表稍微复杂一些。缺点是如果查询之间会出现某种错误，那么这个数字永远不会被使用，所以我的解决方案会保持顺序。
答案 6 :(得分：0)
MS SQL Server 2008架构设置：
CREATE TABLE Table1
([color] varchar(10), [id] int)
;
INSERT INTO Table1
([color], [id])
VALUES
('Red',(select isnull(case when (max(id)/50000)%3 = 1 and
max(id)%50000 = 0 then max(id)+100000 else
max(id) end,0)+1
from Table1 where color = 'Red'));
INSERT INTO Table1 ([color], [id]) VALUES ('Red',50000);
INSERT INTO Table1
([color], [id])
VALUES
('Red',(select isnull(case when (max(id)/50000)%3 = 1 and
max(id)%50000 = 0 then max(id)+100000 else
max(id) end,0)+1
from Table1 where color = 'Red'));
INSERT INTO Table1
([color], [id])
VALUES
('Blue',(select isnull(case when (max(id)/50000)%3 = 2 and
max(id)%50000 = 0 then max(id)+100000 else
max(id) end,50000)+1
from Table1 where color = 'Blue'));
INSERT INTO Table1
([color], [id])
VALUES
('Green',(select isnull(case when (max(id)/50000)%3 = 0 and
max(id)%50000 = 0 then max(id)+100000 else
max(id) end,100000)+1
from Table1 where color = 'Green'));
查询1 ：
SELECT *
FROM Table1
<强> Results ：
| COLOR | ID |
|-------|--------|
| Red | 1 |
| Red | 50000 |
| Red | 150001 |
| Blue | 50001 |
| Green | 100001 |
答案 7 :(得分：0)
这是我对挑战的贡献。不需要额外的表，应该是并发安全的，并且可以处理批量更新。可能不是最快，但它的工作原理。它基本上将要插入的行复制到一个单独的表中，为每种颜色创建ID，最后将所有内容移动到目标表。
Create Trigger Trg_CreateID ON dbo.Cards instead of insert
as
begin
set nocount on
-- declare a working table holding intermediate results
declare @Tmp Table (cardID int, cardColor char(1), cardNumber char(20))
-- copy the data to be inserted in our working table
insert into @Tmp select * from inserted
declare @Id int
-- fill in the Id's once per color
select @Id=coalesce (max(cardID),0) from dbo.Cards where cardColor='Red'
update @Tmp set cardID = @Id, @Id=@id+1 where cardColor='Red'
select @Id=coalesce(max(cardID),50000) from dbo.Cards where cardColor='Blue'
update @Tmp set cardID = @Id, @Id=@id+1 where cardColor='Blue'
select @Id=coalesce(max(cardID),100000) from dbo.Cards where cardColor='Gree'
update @Tmp set cardID = @Id, @Id=@id+1 where cardColor='Green'
-- do the actual insert here
insert into dbo.Cards select * from @tmp
end
它假设一个表Cards就像这样
CREATE TABLE [dbo].[Cards]
(
[cardID] [int] NOT NULL,
[cardColor] [char](1) NOT NULL,
[cardNumber] [char](20) NOT NULL
) ON [PRIMARY]
我在cardID列中添加了一个约束，允许在插入语句中省略它
ALTER TABLE [dbo].[Cards]
ADD CONSTRAINT [DF_Cards_cardID] DEFAULT ((0)) FOR [cardID]
答案 8 :(得分：0)
编辑＃1：我更新了触发器（IF UPDATE），存储过程和最后两个例子。
CREATE TABLE dbo.CustomSequence
(
CustomSequenceID INT IDENTITY(1,1) PRIMARY KEY,
SequenceName NVARCHAR(128) NOT NULL, -- or SYSNAME
UNIQUE(SequenceName),
RangeStart INT NOT NULL,
RangeEnd INT NOT NULL,
CHECK(RangeStart < RangeEnd),
CurrentValue INT NULL,
CHECK(RangeStart <= CurrentValue AND CurrentValue <= RangeEnd)
);
GO
CREATE TRIGGER trgIU_CustomSequence_VerifyRange
ON dbo.CustomSequence
AFTER INSERT, UPDATE
AS
BEGIN
IF (UPDATE(RangeStart) OR UPDATE(RangeEnd)) AND EXISTS
(
SELECT *
FROM inserted i
WHERE EXISTS
(
SELECT * FROM dbo.CustomSequence cs
WHERE cs.CustomSequenceID <> i.CustomSequenceID
AND i.RangeStart <= cs.RangeEnd
AND i.RangeEnd >= cs.RangeStart
)
)
BEGIN
ROLLBACK TRANSACTION;
RAISERROR(N'Range overlapping error', 16, 1);
END
END;
GO
--TRUNCATE TABLE dbo.CustomSequence
INSERT dbo.CustomSequence (SequenceName, RangeStart, RangeEnd)
SELECT N'Red Card', 1, 50000 UNION ALL
SELECT N'Blue Card', 50001, 100000 UNION ALL
SELECT N'Green Card', 100001, 150000;
GO
-- Test for overlapping range
INSERT dbo.CustomSequence (SequenceName, RangeStart, RangeEnd)
VALUES (N'Yellow Card', -100, +100);
GO
/*
Msg 50000, Level 16, State 1, Procedure trgIU_CustomSequence_VerifyRange, Line 20
Range overlapping error
Msg 3609, Level 16, State 1, Line 1
The transaction ended in the trigger. The batch has been aborted.
*/
GO
-- This procedure tries to reserve
CREATE PROCEDURE dbo.SequenceReservation
(
@CustomSequenceID INT, -- You could use also @SequenceName
@IDsCount INT, -- How many IDs do we/you need ? (Needs to be greather than 0)
@LastID INT OUTPUT
)
AS
BEGIN
DECLARE @StartTranCount INT, @SavePoint VARCHAR(32);
SET @StartTranCount = @@TRANCOUNT;
IF @StartTranCount = 0 -- There is an active transaction ?
BEGIN
BEGIN TRANSACTION -- If not then it starts a "new" transaction
END
ELSE -- If yes then "save" a save point -- see http://technet.microsoft.com/en-us/library/ms188378.aspx
BEGIN
DECLARE @ProcID INT, @NestLevel INT;
SET @ProcID = @@PROCID;
SET @NestLevel = @@NESTLEVEL;
SET @SavePoint = CONVERT(VARCHAR(11), @ProcID) + ',' + CONVERT(VARCHAR(11), @NestLevel);
SAVE TRANSACTION @SavePoint;
END
BEGIN TRY
UPDATE dbo.CustomSequence
SET @LastID = CurrentValue = ISNULL(CurrentValue, 0) + @IDsCount
WHERE CustomSequenceID = @CustomSequenceID;
IF @@ROWCOUNT = 0
RAISERROR(N'Invalid sequence', 16, 1);
COMMIT TRANSACTION;
END TRY
BEGIN CATCH
IF @StartTranCount = 0
BEGIN
ROLLBACK TRANSACTION;
END
ELSE -- @StartTranCount > 0
BEGIN
ROLLBACK TRANSACTION @SavePoint
END
DECLARE @ErrorMessage NVARCHAR(2048), @ErrorSeverity INT, @ErrorState INT;
SELECT @ErrorMessage = ERROR_MESSAGE(), @ErrorSeverity = ERROR_SEVERITY(), @ErrorState = ERROR_STATE();
RAISERROR (@ErrorMessage, @ErrorSeverity, @ErrorState);
END CATCH;
END;
GO
SELECT * FROM dbo.CustomSequence;
GO
-- Example usage #1
DECLARE @LastID INT;
EXEC dbo.SequenceReservation
@CustomSequenceID = 1, -- Red Card
@IDsCount = 2, -- How many IDs ?
@LastID = @LastID OUTPUT;
SELECT @LastID - 2 + 1 AS [FirstID], @LastID AS [LastID];
GO
-- Example usage #2
DECLARE @LastID INT;
EXEC dbo.SequenceReservation
@CustomSequenceID = 1, -- Red Card
@IDsCount = 7, -- How many IDs ?
@LastID = @LastID OUTPUT;
SELECT @LastID - 7 + 1 AS [FirstID], @LastID AS [LastID];
SELECT * FROM dbo.CustomSequence;
GO
结果：
CustomSequenceID SequenceName RangeStart RangeEnd CurrentValue
---------------- ------------ ----------- ----------- ------------
1 Red Card 1 50000 9
2 Blue Card 50001 100000 NULL
3 Green Card 100001 150000 NULL
答案 9 :(得分：-2)
* 此解决方案适用于单行插入，多个插入的并发需要不同的方法。在评论中讨论了更多细节*
如果没有创建表的选项，那么你可以使用而不是触发器（在oracle中调整之前的触发器）。
使用触发器内的特定条件来设置Identity列的范围。以下是如何实施解决方案的示例。
表格
CREATE TABLE REQUEST_TABLE(
REQ_ID numeric(8, 0) NOT NULL,
REQ_COLOR VARCHAR(30) NOT NULL
); -- I have used this sample table
而非触发
CREATE TRIGGER tg_req_seq ON REQUEST_TABLE
INSTEAD OF INSERT AS
DECLARE @REQ_ID INT
DECLARE @REQ_COLOR VARCHAR(30)
DECLARE @REQ_START INT
BEGIN
SELECT @REQ_COLOR= (SELECT ISNULL(REQ_COLOR,'NA') FROM INSERTED)
SELECT @REQ_START = (SELECT CASE WHEN @REQ_COLOR = 'Red' THEN 0
WHEN @REQ_COLOR = 'Blue' THEN 50000
ELSE 100000 END)
SELECT @REQ_ID = ISNULL(MAX(REQ_ID),@REQ_START)+1 FROM REQUEST_TABLE
WHERE REQ_COLOR = @REQ_COLOR
INSERT INTO REQUEST_TABLE (REQ_ID,REQ_COLOR)
VALUES (@REQ_ID,@REQ_COLOR)
END;
现在经过一些插入语句
INSERT INTO REQUEST_TABLE VALUES(NULL,'Red');
INSERT INTO REQUEST_TABLE VALUES(NULL,'Red');
INSERT INTO REQUEST_TABLE VALUES(NULL,'Red');
INSERT INTO REQUEST_TABLE VALUES(NULL,'Blue');
INSERT INTO REQUEST_TABLE VALUES(NULL,'Blue');
INSERT INTO REQUEST_TABLE VALUES(NULL,'Blue');
INSERT INTO REQUEST_TABLE VALUES(NULL,'Yellow');
INSERT INTO REQUEST_TABLE VALUES(NULL,'Yellow');
INSERT INTO REQUEST_TABLE VALUES(NULL,'Yellow');
我在SqlFiddle中添加了相同的结果。如果我错过了要包含的内容，请告诉我。
修改
更新Fiddle以满足灵活需求。