最好的选择是DROP和CREATE外键约束。

我在这篇文章中没有找到对我“原样”工作的例子，如果外键引用不同的模式，一个不会工作，如果外键引用多列，另一个也不会工作。这个脚本同时考虑多个模式和每个外键的多个列。

下面是生成“ADD CONSTRAINT”语句的脚本，对于多列，它将用逗号分隔它们(确保在执行DROP语句之前保存此输出):

PRINT N'-- CREATE FOREIGN KEY CONSTRAINTS --';

SET NOCOUNT ON;
SELECT '
PRINT N''Creating '+ const.const_name +'...''
GO
ALTER TABLE ' + const.parent_obj + '
    ADD CONSTRAINT ' + const.const_name + ' FOREIGN KEY (
            ' + const.parent_col_csv + '
            ) REFERENCES ' + const.ref_obj + '(' + const.ref_col_csv + ')
GO'
FROM (
    SELECT QUOTENAME(fk.NAME) AS [const_name]
        ,QUOTENAME(schParent.NAME) + '.' + QUOTENAME(OBJECT_name(fkc.parent_object_id)) AS [parent_obj]
        ,STUFF((
                SELECT ',' + QUOTENAME(COL_NAME(fcP.parent_object_id, fcp.parent_column_id))
                FROM sys.foreign_key_columns AS fcP
                WHERE fcp.constraint_object_id = fk.object_id
                FOR XML path('')
                ), 1, 1, '') AS [parent_col_csv]
        ,QUOTENAME(schRef.NAME) + '.' + QUOTENAME(OBJECT_NAME(fkc.referenced_object_id)) AS [ref_obj]
        ,STUFF((
                SELECT ',' + QUOTENAME(COL_NAME(fcR.referenced_object_id, fcR.referenced_column_id))
                FROM sys.foreign_key_columns AS fcR
                WHERE fcR.constraint_object_id = fk.object_id
                FOR XML path('')
                ), 1, 1, '') AS [ref_col_csv]
    FROM sys.foreign_key_columns AS fkc
    INNER JOIN sys.foreign_keys AS fk ON fk.object_id = fkc.constraint_object_id
    INNER JOIN sys.objects AS oParent ON oParent.object_id = fkc.parent_object_id
    INNER JOIN sys.schemas AS schParent ON schParent.schema_id = oParent.schema_id
    INNER JOIN sys.objects AS oRef ON oRef.object_id = fkc.referenced_object_id
    INNER JOIN sys.schemas AS schRef ON schRef.schema_id = oRef.schema_id
    GROUP BY fkc.parent_object_id
        ,fkc.referenced_object_id
        ,fk.NAME
        ,fk.object_id
        ,schParent.NAME
        ,schRef.NAME
    ) AS const
ORDER BY const.const_name

下面是生成“DROP CONSTRAINT”语句的脚本:

PRINT N'-- DROP FOREIGN KEY CONSTRAINTS --';

SET NOCOUNT ON;

SELECT '
PRINT N''Dropping ' + fk.NAME + '...''
GO
ALTER TABLE [' + sch.NAME + '].[' + OBJECT_NAME(fk.parent_object_id) + ']' + ' DROP  CONSTRAINT ' + '[' + fk.NAME + ']
GO'
FROM sys.foreign_keys AS fk
INNER JOIN sys.schemas AS sch ON sch.schema_id = fk.schema_id
ORDER BY fk.NAME

实际上，你应该能够像暂时禁用其他约束一样禁用外键约束:

Alter table MyTable nocheck constraint FK_ForeignKeyConstraintName

只需确保在约束名称中列出的第一个表上禁用了约束。例如，如果我的外键约束是FK_LocationsEmployeesLocationIdEmployeeId，我想使用以下:

Alter table Locations nocheck constraint FK_LocationsEmployeesLocationIdEmployeeId

尽管违反这个约束会产生一个错误，这个错误不一定会将该表作为冲突的来源。

SET NOCOUNT ON

DECLARE @table TABLE(
   RowId INT PRIMARY KEY IDENTITY(1, 1),
   ForeignKeyConstraintName NVARCHAR(200),
   ForeignKeyConstraintTableSchema NVARCHAR(200),
   ForeignKeyConstraintTableName NVARCHAR(200),
   ForeignKeyConstraintColumnName NVARCHAR(200),
   PrimaryKeyConstraintName NVARCHAR(200),
   PrimaryKeyConstraintTableSchema NVARCHAR(200),
   PrimaryKeyConstraintTableName NVARCHAR(200),
   PrimaryKeyConstraintColumnName NVARCHAR(200),
   UpdateRule NVARCHAR(100),
   DeleteRule NVARCHAR(100)   
)

INSERT INTO @table(ForeignKeyConstraintName, ForeignKeyConstraintTableSchema, ForeignKeyConstraintTableName, ForeignKeyConstraintColumnName)
SELECT 
   U.CONSTRAINT_NAME, 
   U.TABLE_SCHEMA, 
   U.TABLE_NAME, 
   U.COLUMN_NAME
FROM 
   INFORMATION_SCHEMA.KEY_COLUMN_USAGE U
      INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS C
         ON U.CONSTRAINT_NAME = C.CONSTRAINT_NAME
WHERE
   C.CONSTRAINT_TYPE = 'FOREIGN KEY'

UPDATE @table SET
   T.PrimaryKeyConstraintName = R.UNIQUE_CONSTRAINT_NAME,
   T.UpdateRule = R.UPDATE_RULE,
   T.DeleteRule = R.DELETE_RULE
FROM 
   @table T
      INNER JOIN INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS R
         ON T.ForeignKeyConstraintName = R.CONSTRAINT_NAME

UPDATE @table SET
   PrimaryKeyConstraintTableSchema  = TABLE_SCHEMA,
   PrimaryKeyConstraintTableName  = TABLE_NAME
FROM @table T
   INNER JOIN INFORMATION_SCHEMA.TABLE_CONSTRAINTS C
      ON T.PrimaryKeyConstraintName = C.CONSTRAINT_NAME

UPDATE @table SET
   PrimaryKeyConstraintColumnName = COLUMN_NAME
FROM @table T
   INNER JOIN INFORMATION_SCHEMA.KEY_COLUMN_USAGE U
      ON T.PrimaryKeyConstraintName = U.CONSTRAINT_NAME

--SELECT * FROM @table

SELECT '
BEGIN TRANSACTION
BEGIN TRY'

--DROP CONSTRAINT:
SELECT
   '
 ALTER TABLE [' + ForeignKeyConstraintTableSchema + '].[' + ForeignKeyConstraintTableName + '] 
 DROP CONSTRAINT ' + ForeignKeyConstraintName + '
   '
FROM
   @table

SELECT '
END TRY

BEGIN CATCH
   ROLLBACK TRANSACTION
   RAISERROR(''Operation failed.'', 16, 1)
END CATCH

IF(@@TRANCOUNT != 0)
BEGIN
   COMMIT TRANSACTION
   RAISERROR(''Operation completed successfully.'', 10, 1)
END
'

--ADD CONSTRAINT:
SELECT '
BEGIN TRANSACTION
BEGIN TRY'

SELECT
   '
   ALTER TABLE [' + ForeignKeyConstraintTableSchema + '].[' + ForeignKeyConstraintTableName + '] 
   ADD CONSTRAINT ' + ForeignKeyConstraintName + ' FOREIGN KEY(' + ForeignKeyConstraintColumnName + ') REFERENCES [' + PrimaryKeyConstraintTableSchema + '].[' + PrimaryKeyConstraintTableName + '](' + PrimaryKeyConstraintColumnName + ') ON UPDATE ' + UpdateRule + ' ON DELETE ' + DeleteRule + '
   '
FROM
   @table

SELECT '
END TRY

BEGIN CATCH
   ROLLBACK TRANSACTION
   RAISERROR(''Operation failed.'', 16, 1)
END CATCH

IF(@@TRANCOUNT != 0)
BEGIN
   COMMIT TRANSACTION
   RAISERROR(''Operation completed successfully.'', 10, 1)
END'

GO

找到约束条件

SELECT * 
FROM sys.foreign_keys
WHERE referenced_object_id = object_id('TABLE_NAME')

执行由此SQL生成的SQL

SELECT 
    'ALTER TABLE ' +  OBJECT_SCHEMA_NAME(parent_object_id) +
    '.[' + OBJECT_NAME(parent_object_id) + 
    '] DROP CONSTRAINT ' + name
FROM sys.foreign_keys
WHERE referenced_object_id = object_id('TABLE_NAME')

西夫韦。

注意:增加了删除约束的解决方案，这样可以删除或修改表而没有任何约束错误。

如果你想禁用数据库中的所有约束，只需运行以下代码:

-- disable all constraints
EXEC sp_MSforeachtable "ALTER TABLE ? NOCHECK CONSTRAINT all"

要将它们重新打开，运行:(打印当然是可选的，它只是列出表)

-- enable all constraints
exec sp_MSforeachtable @command1="print '?'", @command2="ALTER TABLE ? WITH CHECK CHECK CONSTRAINT all"

我发现它在将数据从一个数据库填充到另一个数据库时很有用。这是比放弃约束更好的方法。正如您所提到的，当删除数据库中的所有数据并重新填充它时(例如在测试环境中)，它非常方便。

如果您正在删除所有数据，您可能会发现这个解决方案是有用的。

有时禁用所有触发器也很方便，你可以在这里看到完整的解决方案。

要禁用约束，您可以使用NOCHECK更改表

ALTER TABLE [TABLE_NAME] NOCHECK CONSTRAINT [ALL|CONSTRAINT_NAME]

要使您必须使用双重检查:

ALTER TABLE [TABLE_NAME] WITH CHECK CHECK CONSTRAINT [ALL|CONSTRAINT_NAME]

启用时请注意双重CHECK CHECK。 ALL表示表中的所有约束。

一旦完成，如果您需要检查状态，使用这个脚本列出约束状态。会很有帮助:

    SELECT (CASE 
        WHEN OBJECTPROPERTY(CONSTID, 'CNSTISDISABLED') = 0 THEN 'ENABLED'
        ELSE 'DISABLED'
        END) AS STATUS,
        OBJECT_NAME(CONSTID) AS CONSTRAINT_NAME,
        OBJECT_NAME(FKEYID) AS TABLE_NAME,
        COL_NAME(FKEYID, FKEY) AS COLUMN_NAME,
        OBJECT_NAME(RKEYID) AS REFERENCED_TABLE_NAME,
        COL_NAME(RKEYID, RKEY) AS REFERENCED_COLUMN_NAME
   FROM SYSFOREIGNKEYS
ORDER BY TABLE_NAME, CONSTRAINT_NAME,REFERENCED_TABLE_NAME, KEYNO