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]

How to check a constraint is exist or not ?

REFERENTIAL constraints are saved in REFERENTIAL_CONSTRAINTS table.

SELECT

    *

    FROM INFORMATION_SCHEMA.REFERENTIAL_CONSTRAINTS

    WHERE CONSTRAINT_NAME   ='FK_EVENT_CONFIGURATION_SCREEN_MASTER'