SQL Server中層次結構的遞歸克隆

Question

我在表中有一個層次結構：

Configuration 
(
    ConfigurationId int identity primary key,
    Name nvarchar(100),
    Value nvarchar(100),
    ParentId` int foreign key referencing ConfigurationId
)

我的任務是克隆具有所有子代的父代，並保持子代的結構。 請記住， ConfigurationId是身份，它將需要保留身份，不一定必須從1開始。我使用與IsClone參數用於插入/更新的過程相同的過程。

過程如下所示：

ALTER PROCEDURE [dbo].[Configuration_Save]
    @ConfigurationId INT,
    @Name NVARCHAR(500),
    @Value NVARCHAR(500),
    @ParentId INT,
    @IsClone BIT
AS
BEGIN
    IF @IsClone = 0
    BEGIN
        IF (@ConfigurationId = 0)
        BEGIN
            INSERT INTO [Configuration]([Name], [Value], [ParentId])
            VALUES (@Name, @Value, @ParentId)
         END
         ELSE
         BEGIN
            UPDATE [Configuration] 
            SET [Name] = @Name, 
                [Value] = @Value, 
                ParentId = @ParentId
            WHERE ConfigurationId = @ConfigurationId
        END
    END
    ELSE -- IF IsClone = 1
    BEGIN
        DECLARE @SourceConfigid INT
        SET @SourceConfigid = @ConfigurationId

        DECLARE @ClonedConfigId INT

        INSERT INTO [Configuration] ([Name], [Value], ParentId)
        VALUES (@Name, @Value, NULL)

        SET @ClonedConfigId = SCOPE_IDENTITY()

       -- solution goes here

    END

    SELECT @ConfigurationId
END

當前數據如下所示：

  ConfigurationId    Name          Value   ParentId
  -------------------------------------------------------
    1                prod          NULL      NULL
    2                Security      NULL        1
    3                SecurityKey   NULL        2
    4                Issuer        NULL        2
    5                Audience      NULL        2
    6                SyncServer    NULL        1
    7                Address       NULL        6
    8                SmtpClient    NULL        1
    9                Host          NULL        8
    10               Port          NULL        8
    11               EnableSsl     NULL        8
    12               Username      NULL        8
    13               Password      NULL        8
    14               FromEmail     NULL        8
    15               Proxy         NULL        1
    16               UseProxy      NULL       15
    17               ProxyAddress  NULL       15
    18               AddressList   NULL       15
    19               Report        NULL        1
    20               ApiUrl        NULL       19

我希望能夠通過插入新的根配置來克隆根配置（在上一個示例中，其ParentId = NULL ，在ConfigurationId = 1且Name = prod ），該根配置我通過執行存儲過程輸入名稱，並將行復制到當前位置唯一的區別是作為身份的ConfigurationId和應在保持層次結構的同時根據新ConfigurationId更改的ParentId 。

所需數據如下所示：

   ConfigurationId   Name          Value   ParentId
   ------------------------------------------------
    1                prod          NULL      NULL
    2                Security      NULL         1
    3                SecurityKey   NULL         2
    4                Issuer        NULL         2
    5                Audience      NULL         2
    6                SyncServer    NULL         1
    7                Address       NULL         6
    8                SmtpClient    NULL         1
    9                Host          NULL         8
    10               Port          NULL         8
    11               EnableSsl     NULL         8
    12               Username      NULL         8
    13               Password      NULL         8
    14               FromEmail     NULL         8
    15               Proxy         NULL         1
    16               UseProxy      NULL        15
    17               ProxyAddress  NULL        15
    18               AddressList   NULL        15
    19               Report        NULL         1
    20               ApiUrl        NULL        19
    21               prod2         NULL      NULL
    22               Security      NULL        21
    23               SecurityKey   NULL        22
    24               Issuer        NULL        22
    25               Audience      NULL        22
    26               SyncServer    NULL        21
    27               Address       NULL        26
    28               SmtpClient    NULL        21
    29               Host          NULL        28
    30               Port          NULL        28
    31               EnableSsl     NULL        28
    32               Username      NULL        28
    33               Password      NULL        28
    34               FromEmail     NULL        28
    35               Proxy         NULL        21
    36               UseProxy      NULL        35
    37               ProxyAddress  NULL        35
    38               AddressList   NULL        35
    39               Report        NULL        21
    40               ApiUrl        NULL        39

與嵌套游標，合並和調用過程/函數相比，我更喜歡CTE解決方案。 我嘗試了幾種以類似名稱列出的解決方案，但沒有成功。

編輯1：示例數據的格式

編輯2：只能克隆根節點，這意味着只有ParentId = NULL的條目才是克隆選項。

任何幫助，將不勝感激。

Answer 1

有許多答案顯示了如何使用附加某些路徑信息的遞歸CTE。 這是一個需要針對您的排序首選項進行調整的示例：

;with cteHierarchy  AS (
SELECT ConfigurationId, NAme, Value, ParentId,
    CAST(ConfigurationID AS varchar(255)) As HierarchyPath
FROM #Configuration WHERE ParentId IS NULL
UNION ALL
SELECT C.ConfigurationId, C.NAme, C.Value, C.ParentId,
    --I prefer CONCAT(), but not sure of your SQL version
    CAST(P.HierarchyPath + '.' + CAST(C.ConfigurationID AS varchar(255)) as varchar(255)) As HierarchyPath
FROM #Configuration C
JOIN cteHierarchy P ON C.ParentId = P.ConfigurationId
)

SELECT * FROM cteHierarchy Order By HierarchyPath

Answer 2

以下代碼使用CTE和update來復制指定層次結構。 CTE從根到葉遞歸地遍歷，並提供一個insert ，該insert添加行的“副本”。 insert上的output子句產生一張修正對表，其中包含每個新行的新舊ConfigurationId值。 由於output子句只能訪問插入的列值，因此我們“借用”一列（ Value ）以存儲舊的ConfigurationId值。 然后使用update來設置兩列： ParentId值被更新以引用復制的行，而Value值從原始行中恢復。

請注意，繁忙的工作應包裝在事務中。 它可以確保復制完成或不遺漏任何雜物，並且需要防止其他會話看到不完整的結果或更改完成復制所需的舊Value數據。

-- Sample data.
declare @Configuration as Table (
  ConfigurationId Int Identity,
  Name NVarChar(100),
  Value NVarChar(100),
  ParentId Int );

insert into @Configuration ( Name, Value, ParentId ) values
  ( 'prod', NULL, NULL ),
  ( 'Security', NULL, 1 ),
  ( 'SecurityKey', NULL, 2 ),
  ( 'Issuer', NULL, 2 ),
  ( 'Audience', NULL, 2 ),
  ( 'SyncServer', NULL, 1 ),
  ( 'Address', NULL, 6 );
    --8                SmtpClient    NULL        1
    --9                Host          NULL        8
    --10               Port          NULL        8
    --11               EnableSsl     NULL        8
    --12               Username      NULL        8
    --13               Password      NULL        8
    --14               FromEmail     NULL        8
    --15               Proxy         NULL        1
    --16               UseProxy      NULL       15
    --17               ProxyAddress  NULL       15
    --18               AddressList   NULL       15
    --19               Report        NULL        1
    --20               ApiUrl        NULL       19

-- Raw sample data.
select * from @Configuration;

-- Tree sample data.
with Configuration as (
  select ConfigurationId, Name, Value, ParentId,
    Cast( Right( '0000' + Cast( ConfigurationId as NVarChar(4) ), 4 ) as NVarChar(1024) ) as Path
    from @Configuration
    where ParentId is NULL
  union all
  select CC.ConfigurationId, CC.Name, CC.Value, CC.ParentId,
    Cast( Path + N'→' + Right( '0000' + Cast( CC.ConfigurationId as NVarChar(4) ), 4 ) as NVarChar(1024) )
    from Configuration as PC inner join
      @Configuration as CC on CC.ParentId = PC.ConfigurationId )
  select *
    from Configuration
    order by Path;

-- Copy the tree.
declare @RootConfigurationId as Int = 1;
declare @Fixups as Table ( OriginalConfigurationId NVarChar(10), CopyConfigurationId Int );

-- NB: The isolation level needs to guarantee that the   Value   in the
--   source rows doesn't get changed whilst we fiddle about, nor do we want anyone else peeking.
begin transaction;

-- Copy the tree and save the new identity values.
--   We cheat and tuck the old   ConfigurationId   into the   Value   column so that the
--   output   clause can save the original and copy   ConfigurationId   values for fixup.
with Configuration as (
select ConfigurationId, Name, Value, ParentId
  from @Configuration
  where ConfigurationId = @RootConfigurationId
union all
select CC.ConfigurationId, CC.Name, CC.Value, CC.ParentId
  from Configuration as PC inner join
    @Configuration as CC on CC.ParentId = PC.ConfigurationId )
insert into @Configuration ( Name, Value, ParentId )
  output inserted.Value, inserted.ConfigurationId into @Fixups
  select Name, Cast( ConfigurationId as NVarChar(10) ), ParentId
    from Configuration as C;

-- Display the intermediate results.
select * from @Fixups;
select * from @Configuration;

-- Fix up the parentage and replace the original values.
update C
  set C.ParentId = F2.CopyConfigurationId, Value = CV.Value
  from @Configuration as C inner join -- New rows to be fixed.
    @Fixups as F on F.CopyConfigurationId = C.ConfigurationId inner join -- New row identity values.
    @Configuration as CV on CV.ConfigurationId = F.OriginalConfigurationId left outer join -- Original   Value .
    @Fixups as F2 on F2.OriginalConfigurationId = C.ParentId; -- Lookup the new   ParentId , if any, for each row.

-- Raw sample data.
select * from @Configuration;

-- Tree sample data.
with Configuration as (
  select ConfigurationId, Name, Value, ParentId,
    Cast( Right( '0000' + Cast( ConfigurationId as NVarChar(4) ), 4 ) as NVarChar(1024) ) as Path
    from @Configuration
    where ParentId is NULL
  union all
  select CC.ConfigurationId, CC.Name, CC.Value, CC.ParentId,
    Cast( Path + N'→' + Right( '0000' + Cast( CC.ConfigurationId as NVarChar(4) ), 4 ) as NVarChar(1024) )
    from Configuration as PC inner join
      @Configuration as CC on CC.ParentId = PC.ConfigurationId )
  select *
    from Configuration
    order by Path;

commit transaction;