Sql server 如何临时或按需级联删除？

有时我试图删除MSSQL中的一行，但由于外键约束的引用，我在层次结构中陷入了无数次删除。 是否有任何快速方法可以自动级联删除，而无需使用级联删除设置外键约束？只是这一次我需要级联删除。。。随需应变——并非总是如此

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有机会吗？任何等价物？

因为您需要它用于一次性用途，但不希望它总是存在，所以我认为您最好将它写入存储过程

只需先从最远的表中删除，然后以您的方式返回树

下面是一个例子：

Create Proc CascaseDeleteMyTable
    @MyTableId Int
As


Delete From ChildTable33 Where ChildParent33Id In (Select ChildParent33Id From ChildParent33 Where MyTableId = @MyTableId)

Delete From ChildTable2 Where MyTableId = @MyTableId

GO

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如果您想要一个点对点动态sql解决方案，这将使用递归查询为从特殊键派生的外键构建表层次结构。然后，它生成需要执行的delete语句，以便（希望如此）从表中删除特定行

use AdventureWorks2012

declare @tablename sysname = N'Production.Product';
declare @primarykeycolumn sysname = N'ProductId';
declare @value nvarchar(128) = '2';
declare @sql nvarchar(max);

;with tableHierarchy as (
select
    object_id = p.object_id
  , parent_id = cast(null as int)
  , schemaName = schema_name(p.schema_id)
  , tableName = object_name(p.object_id)
  , parentObjectName = cast(null as sysname)
  , parentToChild = cast(object_name(p.object_id) as varchar(max))
  , childToParent = cast(object_name(p.object_id) as varchar(max))
  , treelevel = 0
  , keyName = p.name
  , columnName = c.name
  , columnId = c.column_id
  , parentColumnName = c.name
from sys.objects as p
  inner join sys.columns c
    on p.object_id = c.object_id
where p.object_id  = object_id(@tablename)
  and c.name = @primarykeycolumn
union all
select
    object_id = fk.parent_object_id
  , parent_id = fk.referenced_object_id
  , schemaName = schema_name(fk.schema_id)
  , tableName = object_name(fk.parent_object_id)
  , parentObjectName = object_name(fk.referenced_object_id)
  , parentToChild = parentToChild + ' \ ' + cast(object_name(fk.parent_object_id) as varchar(128))
  , childToParent = cast(object_name(fk.parent_object_id) as varchar(128)) + ' \ ' + childToParent
  , treelevel = th.treelevel + 1
  , keyName = fk.name
  , columnName = c.name
  , columnId = c.column_id
  , parentColumnName = rc.name
from tableHierarchy as th
  inner join sys.foreign_keys as fk
    on fk.referenced_object_id = th.object_id
   and fk.referenced_object_id != fk.parent_object_id 
  inner join sys.foreign_key_columns fkc
    on fk.object_id = fkc.constraint_object_id
  and fkc.referenced_column_id = th.columnId
  inner join sys.columns c
    on fkc.parent_object_id = c.object_id
   and fkc.parent_column_id = c.column_id
  inner join sys.columns rc
    on fkc.referenced_object_id = rc.object_id
   and fkc.referenced_column_id = rc.column_id
)
select @sql = stuff((
  select 
      char(10)
    --+'/* treelevel: '+convert(nvarchar(10),treelevel)
    --+' | ' + childtoparent +' */'+char(10)
    +'delete from '+quotename(schemaName)+'.'+quotename(tableName)
    +' where '+quotename(columnName)+' = '+@value+';'
  from tableHierarchy
  group by treelevel, childtoparent, schemaName, tableName, columnName
  order by treelevel desc, childtoparent
  for xml path (''), type).value('.','nvarchar(max)')
  ,1,1,'')
  option ( maxrecursion 100 );

select @sql as CodeGenerated;
--exec sp_executesql @sql;

生成的代码：

delete from [Sales].[SalesOrderDetail] where [ProductID] = 2;
delete from [Production].[BillOfMaterials] where [ComponentID] = 2;
delete from [Production].[BillOfMaterials] where [ProductAssemblyID] = 2;
delete from [Production].[ProductCostHistory] where [ProductID] = 2;
delete from [Production].[ProductDocument] where [ProductID] = 2;
delete from [Production].[ProductInventory] where [ProductID] = 2;
delete from [Production].[ProductListPriceHistory] where [ProductID] = 2;
delete from [Production].[ProductProductPhoto] where [ProductID] = 2;
delete from [Production].[ProductReview] where [ProductID] = 2;
delete from [Purchasing].[ProductVendor] where [ProductID] = 2;
delete from [Purchasing].[PurchaseOrderDetail] where [ProductID] = 2;
delete from [Sales].[ShoppingCartItem] where [ProductID] = 2;
delete from [Sales].[SpecialOfferProduct] where [ProductID] = 2;
delete from [Production].[TransactionHistory] where [ProductID] = 2;
delete from [Production].[WorkOrder] where [ProductID] = 2;
delete from [Production].[Product] where [ProductID] = 2;

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如果没有定义外键约束，数据库如何进行级联删除？它不知道哪些列与哪些列相关。@GordonLinoff我认为有外键约束（这就是为什么他不能只删除他想要的行），只是没有设置为cascade delete。@GordonLinoff——我把问题说错了。请在我编辑后再读一遍。谢谢SqlZim，尽管如此，还是要澄清一下。谢谢！这很整洁。我可以将其作为一个存储过程，并将表名和主键值作为参数——它可以自己计算出其余部分。太好了@比默盖伊很乐意帮忙！