I am having three tables Persons_Description,Persons_Country_Visited,Persons_Fav_Links in SQL Database.I need to maintain the Data Integrity. Persons_Description [P_Id] [bigint] IDENTITY(1,1) NOT NULL, [First_Name] [varchar](255) NOT NULL, [Last_Name] [varchar](255) NOT NULL, [Gender] [varchar](255) NOT NULL, CONSTRAINT [PK_Persons_Description] PRIMARY KEY CLUSTERED (P_Id) P_ID First_Name Last_Name Gender