How to create, alter and Drop a Constraints in SQL SERVER

To alter a constraints we need to drop that constraints first.

then recreate that constraints.

Follow this syntax, to Drop Constraints.

ALTER TABLE [dbo].[TableName]  DROP CONSTRAINT [FK_Config_ConstraintsName]

Follow this syntax, to Create a new Constraints.

ALTER TABLE [dbo].[TableName]  WITH CHECK ADD  CONSTRAINT [FK_Config_ConstraintsName] FOREIGN KEY([Company_Mapping_ID])

REFERENCES [dbo].[Template_Company_Table] ([Template_Company_Mapping_ID])

GO

ALTER TABLE [dbo].[TableName] CHECK CONSTRAINT [FK_Config_ConstraintsName]

GO