我可以删除一个表，如果它存在使用以下代码，但不知道如何做同样的约束:
IF EXISTS(SELECT 1 FROM sys.objects WHERE OBJECT_ID = OBJECT_ID(N'TableName') AND type = (N'U')) DROP TABLE TableName
go
我还使用以下代码添加了约束:
ALTER TABLE [dbo].[TableName]
WITH CHECK ADD CONSTRAINT [FK_TableName_TableName2] FOREIGN KEY([FK_Name])
REFERENCES [dbo].[TableName2] ([ID])
go
当前回答
Declare @FKeyRemoveQuery NVarchar(max)
IF EXISTS(SELECT 1 FROM sys.foreign_keys WHERE parent_object_id = OBJECT_ID(N'dbo.TableName'))
BEGIN
SELECT @FKeyRemoveQuery='ALTER TABLE dbo.TableName DROP CONSTRAINT [' + LTRIM(RTRIM([name])) + ']'
FROM sys.foreign_keys
WHERE parent_object_id = OBJECT_ID(N'dbo.TableName')
EXECUTE Sp_executesql @FKeyRemoveQuery
END
其他回答
ALTER TABLE [dbo].[TableName]
DROP CONSTRAINT FK_TableName_TableName2
您可以使用这些查询为您的表查找所有fk。
Declare @SchemaName VarChar(200) = 'Schema Name'
Declare @TableName VarChar(200) = 'Table name'
-- Find FK in This table.
SELECT
'IF EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id = OBJECT_ID(N''' +
'[' + OBJECT_SCHEMA_NAME(FK.parent_object_id) + '].[' + FK.name + ']'
+ ''') AND parent_object_id = OBJECT_ID(N''' +
'[' + OBJECT_SCHEMA_NAME(FK.parent_object_id) + '].['
+ OBJECT_NAME(FK.parent_object_id) + ']' + ''')) ' +
'ALTER TABLE ' + OBJECT_SCHEMA_NAME(FK.parent_object_id) +
'.[' + OBJECT_NAME(FK.parent_object_id) +
'] DROP CONSTRAINT ' + FK.name
, S.name , O.name, OBJECT_NAME(FK.parent_object_id)
FROM sys.foreign_keys AS FK
INNER JOIN Sys.objects As O
ON (O.object_id = FK.parent_object_id )
INNER JOIN SYS.schemas AS S
ON (O.schema_id = S.schema_id)
WHERE
O.name = @TableName
And S.name = @SchemaName
-- Find the FKs in the tables in which this table is used
SELECT
' IF EXISTS (SELECT * FROM sys.foreign_keys WHERE object_id = OBJECT_ID(N''' +
'[' + OBJECT_SCHEMA_NAME(FK.parent_object_id) + '].[' + FK.name + ']'
+ ''') AND parent_object_id = OBJECT_ID(N''' +
'[' + OBJECT_SCHEMA_NAME(FK.parent_object_id) + '].['
+ OBJECT_NAME(FK.parent_object_id) + ']' + ''')) ' +
' ALTER TABLE ' + OBJECT_SCHEMA_NAME(FK.parent_object_id) +
'.[' + OBJECT_NAME(FK.parent_object_id) +
'] DROP CONSTRAINT ' + FK.name
, S.name , O.name, OBJECT_NAME(FK.parent_object_id)
FROM sys.foreign_keys AS FK
INNER JOIN Sys.objects As O
ON (O.object_id = FK.referenced_object_id )
INNER JOIN SYS.schemas AS S
ON (O.schema_id = S.schema_id)
WHERE
O.name = @TableName
And S.name = @SchemaName
IF (OBJECT_ID('DF_Constraint') IS NOT NULL)
BEGIN
ALTER TABLE [dbo].[tableName]
DROP CONSTRAINT DF_Constraint
END
这在Azure Sql服务器上工作得很顺利:
IF (OBJECT_ID('dbo.FK_company_id', 'F') IS NOT NULL)
BEGIN
ALTER TABLE dbo.table_company DROP CONSTRAINT FK_company_id
END
我想这会对你有帮助……
DECLARE @ConstraintName nvarchar(200)
SELECT
@ConstraintName = KCU.CONSTRAINT_NAME
FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS AS RC
INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE AS KCU
ON KCU.CONSTRAINT_CATALOG = RC.CONSTRAINT_CATALOG
AND KCU.CONSTRAINT_SCHEMA = RC.CONSTRAINT_SCHEMA
AND KCU.CONSTRAINT_NAME = RC.CONSTRAINT_NAME
WHERE
KCU.TABLE_NAME = 'TABLE_NAME' AND
KCU.COLUMN_NAME = 'TABLE_COLUMN_NAME'
IF @ConstraintName IS NOT NULL EXEC('alter table TABLE_NAME drop CONSTRAINT ' + @ConstraintName)
它会根据特定的表和列删除外键约束。
