选择/删除三个自引用多对多关系的SQL查询

Question

我有一个表ProjectLayerContent设计如下：

1. ProjectLayerContentID [INT]
2. ProjectLayerContentName [NVARCHAR（200）]
3. ProjectLayerContentParentID [INT]
4. ScopeIsProjectLayerContent [BIT]
5. ScopeIsProjectLayerContentID [INT]
6. DataTypeIsContentOfContent [BIT]

7. ContentOfContentID [INT]

   • 项目图层内容可能包含父项，也可能没有。对于子项也是如此。
   • 项目图层内容范围可能包含其他项目图层内容。
   • 项目图层内容数据类型可能是另一种内容的类型。

我想要做的是在删除过程中，我想显示一个列表，其中包括如果要删除此项目图层内容将删除的内容。 这几乎就是我所涉及的，但我知道这些结果并不正确

    DECLARE @ProjectLayerContentID INT = 1;
DECLARE @resTable TABLE (
    ProjectLayerContentIDP int,
    ProjLContentType nvarchar(100));

    DECLARE @ProjectLayerContentIDRecursionParam int;
    DECLARE @Type NVARCHAR(MAX);

    DECLARE @resultString NVARCHAR(MAX) = '';

    -- SELECT Project layer content children with recursion

-- SELECT the count of the result from the recursion of the children of the project layer content id passed with the sql parameter in the query
        DECLARE ProjectLayerContentChildren_Cursor CURSOR FOR
        SELECT  ProjectLayerContentID, 'Child(ren)'
        FROM    ProjectLayerContent
        WHERE   ProjectLayerContentParentID = @ProjectLayerContentID

        OPEN ProjectLayerContentChildren_Cursor
        FETCH NEXT FROM ProjectLayerContentChildren_Cursor INTO @ProjectLayerContentIDRecursionParam, @Type
                WHILE @@FETCH_STATUS = 0
                    BEGIN
                        INSERT INTO @resTable SELECT @ProjectLayerContentIDRecursionParam, @Type;
                        ;WITH ProjectLayerContentTotalScopeChildren AS(
                        SELECT  ProjectLayerContentID,CAST('Content(s) of Child(ren)' as varchar(259))   AS ProjLContentType
                        FROM    ProjectLayerContent
                        WHERE   ContentOfContentID = @ProjectLayerContentIDRecursionParam
                        UNION ALL
                        SELECT  Scopechildren.ProjectLayerContentID, CAST('Children Content Of Content of Child(ren)' as varchar(259)) AS ProjLContentType
                        FROM    ProjectLayerContent Scopechildren INNER JOIN
                                ProjectLayerContentTotalScopeChildren projLContents ON Scopechildren.ContentOfContentID = projLContents.ProjectLayerContentID
                        UNION ALL
                        SELECT  children.ProjectLayerContentID, CAST('Child(ren) of Child(ren) of Child(ren)' as varchar(259)) AS ProjLContentType
                        FROM    ProjectLayerContent children INNER JOIN
                                ProjectLayerContentTotalScopeChildren projLContents ON children.ProjectLayerContentParentID = projLContents.ProjectLayerContentID
                        )
                        INSERT INTO @resTable SELECT ProjectLayerContentID, ProjLContentType from ProjectLayerContentTotalScopeChildren
                                            FETCH NEXT FROM ProjectLayerContentChildren_Cursor INTO @ProjectLayerContentIDRecursionParam, @Type
                END
        -- close the cursor
        CLOSE ProjectLayerContentChildren_Cursor
        DEALLOCATE ProjectLayerContentChildren_Cursor


    -----------------------------------------------------------------------------------------------------------
        -- SELECT Project layer content Scope children with recursion
        DECLARE ProjectLayerContent_Cursor CURSOR FOR
        SELECT  ProjectLayerContentID, 'Content Of Content'
        FROM    ProjectLayerContent
        WHERE   ContentOfContentID = @ProjectLayerContentID


        OPEN ProjectLayerContent_Cursor
        FETCH NEXT FROM ProjectLayerContent_Cursor INTO @ProjectLayerContentIDRecursionParam, @Type
                WHILE @@FETCH_STATUS = 0
                    BEGIN
                            INSERT INTO @resTable SELECT @ProjectLayerContentIDRecursionParam, @Type;
                            ;WITH ProjectLayerContentTotalScopeContentOfContent AS(
                            SELECT  ProjectLayerContentID,CAST('Children Content Of Content' as varchar(259))   AS ProjLContentType
                            FROM    ProjectLayerContent
                            WHERE   ContentOfContentID = @ProjectLayerContentIDRecursionParam
                            UNION ALL
                            SELECT  Scopechildren.ProjectLayerContentID, CAST('Children Content Of Content of Children Content Of Content' as varchar(259)) AS ProjLContentType
                            FROM    ProjectLayerContent Scopechildren INNER JOIN
                                    ProjectLayerContentTotalScopeContentOfContent projLContents ON Scopechildren.ContentOfContentID = projLContents.ProjectLayerContentID
                            UNION ALL
                            SELECT  children.ProjectLayerContentID, CAST('Children of Children Content Of Content' as varchar(259)) AS ProjLContentType
                            FROM    ProjectLayerContent children INNER JOIN
                                    ProjectLayerContentTotalScopeContentOfContent projLContents ON children.ProjectLayerContentParentID = projLContents.ProjectLayerContentID
                            )
                            INSERT INTO @resTable SELECT ProjectLayerContentID, ProjLContentType from ProjectLayerContentTotalScopeContentOfContent
                                                FETCH NEXT FROM ProjectLayerContent_Cursor INTO @ProjectLayerContentIDRecursionParam, @Type
                END
        -- close the cursor
        CLOSE ProjectLayerContent_Cursor
        DEALLOCATE ProjectLayerContent_Cursor

        --select the result to present it.
        SELECT * FROM @resTable;

提前致谢。

Answer 1

我发现这个解决方案可以根据需要获得所需的功能。

我创建了存储过程以首先获取此项目图层的所有子项，并创建了一个表来添加结果。因为如果您有一个INSERT INTO EXEC，那么INSERT INTO EXEC的第一个错误将无效存储过程链相互调用。它只适用于第一次，但其他时间会显示错误。

DECLARE @ProjectLayerContentID INT = 1;
DECLARE @ProjectLayerContentIDRecursionParam INT;
DECLARE @Type NVARCHAR(MAX);

DECLARE @resultString NVARCHAR(MAX) = '';

-------Create temp table to insert the results into it
CREATE TABLE #ResTable(
ProjectLayerContentIDP int,
ProjLContentType nvarchar(100));

然后我为所有孩子的select语句创建了一个游标，这个孩子的关系是该项目图层的子项，或者是它的内容。

-- SELECT Project layer content children with recursion

-- SELECT the count of the result from the recursion of the children of the project layer content id passed with the sql parameter in the query

DECLARE ProjectLayerContent_Cursor CURSOR FOR
SELECT  ProjectLayerContentID, CASE WHEN ProjectLayerContentParentID = @ProjectLayerContentID THEN 'Child(ren)' ELSE 'Content(s) of Content(s)' END
FROM    ProjectLayerContent
WHERE   ProjectLayerContentParentID = @ProjectLayerContentID
        OR ContentOfContentID = @ProjectLayerContentID

OPEN ProjectLayerContent_Cursor
FETCH NEXT FROM ProjectLayerContent_Cursor INTO @ProjectLayerContentIDRecursionParam, @Type
        WHILE @@FETCH_STATUS = 0
            BEGIN
                INSERT INTO #ResTable SELECT @ProjectLayerContentIDRecursionParam, @Type;

然后我将调用递归存储过程来获取每个当前项目层内容的chlidren和子项的内容。

Exec DeleteCheck_ProjectLayerContentChildren @ProjectLayerContentIDRecursionParam;
                    FETCH NEXT FROM ProjectLayerContent_Cursor INTO @ProjectLayerContentIDRecursionParam, @Type
                END
    -- close the cursor
    CLOSE ProjectLayerContent_Cursor
    DEALLOCATE ProjectLayerContent_Cursor

在此部分，我们将选择结果，然后从数据库服务器中删除临时表。

        --select the result to present it.
SELECT @resultString =  @resultString + '<br/><u>' + CONVERT(NVARCHAR(MAX), Count(ProjectLayerContentIDP)) + '</u> ' + ProjLContentType
FROM #ResTable
GROUP BY ProjLContentType;
SELECT @resultString;
DROP TABLE #ResTable

以下是我们在上一个查询中已经调用过的递归存储过程

CREATE PROCEDURE  [dbo].[DeleteCheck_ProjectLayerContentChildren]
    @ProjectLayerContentID INT
AS
BEGIN

    DECLARE @ProjectLayerContentIDRecursionParam INT;
    DECLARE @Type NVARCHAR(MAX);

    -- SELECT Project layer content children with recursion

-- SELECT the count of the result from the recursion of the children of the project layer content id passed with the sql parameter in the query.

注意这里我们将Local添加到光标的减速中，因为它会显示创建具有相同名称的光标的错误

        DECLARE ProjectLayerContentChildren_Cursor CURSOR LOCAL FOR
        SELECT  ProjectLayerContentID, CASE WHEN ProjectLayerContentParentID = @ProjectLayerContentID THEN 'Child(ren) of Child(ren)' ELSE 'Child(ren) Content(s) of Content(s)' END
        FROM    ProjectLayerContent
        WHERE   ProjectLayerContentParentID = @ProjectLayerContentID
                OR ContentOfContentID = @ProjectLayerContentID

这个查询的大部分内容与前一个查询相同，但这是针对项目图层内容子项的子项计数，我们不再创建结果表，因为它已经创建，然后我们只需添加结果，我们就拥有了所需的功能，您可以将它应用于两三个以上的自我关系。

OPEN ProjectLayerContentChildren_Cursor
            FETCH NEXT FROM ProjectLayerContentChildren_Cursor INTO @ProjectLayerContentIDRecursionParam, @Type
                    WHILE @@FETCH_STATUS = 0
                        BEGIN
                            INSERT INTO #ResTable SELECT @ProjectLayerContentIDRecursionParam, @Type;
                            Exec DeleteCheck_ProjectLayerContentChildren @ProjectLayerContentIDRecursionParam
                            FETCH NEXT FROM ProjectLayerContentChildren_Cursor INTO @ProjectLayerContentIDRecursionParam, @Type
                        END
            -- close the cursor
            CLOSE ProjectLayerContentChildren_Cursor
            DEALLOCATE ProjectLayerContentChildren_Cursor
    END