如果表存在，我可以使用以下代码删除它，但不知道如何使用约束执行相同操作:
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
Eric Isaacs's答案中提供了更简单的解决方案.但是，它会在任何表上找到约束.如果要针对特定表的外键约束，请使用以下命令:
IF EXISTS (SELECT *
FROM sys.foreign_keys
WHERE object_id = OBJECT_ID(N'FK_TableName_TableName2')
AND parent_object_id = OBJECT_ID(N'dbo.TableName')
)
ALTER TABLE [dbo].[TableName] DROP CONSTRAINT [FK_TableName_TableName2]