REFERENCE制約エラーがあるため、ストアド プロシージャに削除カスケードを実装するためにいくつかの助けが必要です
Create PROCEDURE [dbo].[DeleteProject]
@ProjectID uniqueidentifier
AS
BEGIN
-- Insert statements for procedure here
DELETE FROM [TaskManagementSystem_DB].[dbo].[Projects]
WHERE projectID = @ProjectID
END
プロシージャにカスケード削除を実装しません。
外部キー制約自体にdelete cascaseを実装します。
ALTER TABLE [ChildTable] WITH CHECK ADD CONSTRAINT [FK_ChildTable_Projects] FOREIGN KEY ([ProjectID})
REFERENCES [Project] ([ProjectID])
ON DELETE CASCADE
または、マスターを削除する前に子レコードを明示的に削除する必要があります。
Create PROCEDURE [dbo].[DeleteProject]
@ProjectID uniqueidentifier
AS
BEGIN
DELETE child
FROM [TaskManagementSystem_DB].[dbo].[Projects] proj
JOIN [TaskManagementSystem_DB].[dbo].[ChildTable] child
ON proj.ProjectID = child.ProjectID
DELETE FROM [TaskManagementSystem_DB].[dbo].[Projects]
WHERE projectID = @ProjectID
END
ここでは、選択した基準に一致する、指定されたテーブル内のすべての行を削除する実装を見つけることができます。また、子/孫のレコードなども削除します。
最初に sysforeignkeys テーブルを読み取って子テーブルを見つけ、次にこのプロシージャの再帰呼び出しを使用して、すぐに孤立するレコードをそれらから削除します。すべての子レコードがなくなると、選択したテーブルから行が削除されます:素晴らしい SQL 削除カスケード ストアド プロシージャ!
リンクをたどる際に問題が発生した場合に備えて、コードを次に示します。
CREATE Procedure spDeleteRows
/*
Recursive row delete procedure.
It deletes all rows in the table specified that conform to the criteria selected,
while also deleting any child/grandchild records and so on. This is designed to do the
same sort of thing as Access's cascade delete function. It first reads the sysforeignkeys
table to find any child tables, then deletes the soon-to-be orphan records from them using
recursive calls to this procedure. Once all child records are gone, the rows are deleted
from the selected table. It is designed at this time to be run at the command line. It could
also be used in code, but the printed output will not be available.
*/
(
@cTableName varchar(50), /* name of the table where rows are to be deleted */
@cCriteria nvarchar(1000), /* criteria used to delete the rows required */
@iRowsAffected int OUTPUT /* number of records affected by the delete */
)
As
set nocount on
declare @cTab varchar(255), /* name of the child table */
@cCol varchar(255), /* name of the linking field on the child table */
@cRefTab varchar(255), /* name of the parent table */
@cRefCol varchar(255), /* name of the linking field in the parent table */
@cFKName varchar(255), /* name of the foreign key */
@cSQL nvarchar(1000), /* query string passed to the sp_ExecuteSQL procedure */
@cChildCriteria nvarchar(1000), /* criteria to be used to delete
records from the child table */
@iChildRows int /* number of rows deleted from the child table */
/* declare the cursor containing the foreign key constraint information */
DECLARE cFKey CURSOR LOCAL FOR
SELECT SO1.name AS Tab,
SC1.name AS Col,
SO2.name AS RefTab,
SC2.name AS RefCol,
FO.name AS FKName
FROM dbo.sysforeignkeys FK
INNER JOIN dbo.syscolumns SC1 ON FK.fkeyid = SC1.id
AND FK.fkey = SC1.colid
INNER JOIN dbo.syscolumns SC2 ON FK.rkeyid = SC2.id
AND FK.rkey = SC2.colid
INNER JOIN dbo.sysobjects SO1 ON FK.fkeyid = SO1.id
INNER JOIN dbo.sysobjects SO2 ON FK.rkeyid = SO2.id
INNER JOIN dbo.sysobjects FO ON FK.constid = FO.id
WHERE SO2.Name = @cTableName
OPEN cFKey
FETCH NEXT FROM cFKey INTO @cTab, @cCol, @cRefTab, @cRefCol, @cFKName
WHILE @@FETCH_STATUS = 0
BEGIN
/* build the criteria to delete rows from the child table. As it uses the
criteria passed to this procedure, it gets progressively larger with
recursive calls */
SET @cChildCriteria = @cCol + ' in (SELECT [' + @cRefCol + '] FROM [' +
@cRefTab +'] WHERE ' + @cCriteria + ')'
print 'Deleting records from table ' + @cTab
/* call this procedure to delete the child rows */
EXEC spDeleteRows @cTab, @cChildCriteria, @iChildRows OUTPUT
FETCH NEXT FROM cFKey INTO @cTab, @cCol, @cRefTab, @cRefCol, @cFKName
END
Close cFKey
DeAllocate cFKey
/* finally delete the rows from this table and display the rows affected */
SET @cSQL = 'DELETE FROM [' + @cTableName + '] WHERE ' + @cCriteria
print @cSQL
EXEC sp_ExecuteSQL @cSQL
print 'Deleted ' + CONVERT(varchar, @@ROWCOUNT) + ' records from table ' + @cTableName