Ravi Kiran V wrote:I mean to say that we can maintain a single table , rather than scatering the data across tables,
Data integrity. if you modelled a nullabel one-to-one relationship in a single table its only a matter of time before some applciaiton logic messes the data up. If you have non-nullable fields in a joined table but the relationship is optional your data is safer.
With modern databases, you do need to ramp up the joins to start to hit performance issue and you will know better than us if your application will frequently have to join multiple tables. If you have issues, indices will fix many and denormalizing part of the data will fix more. But I'd hesitate to go straight to denormilzation.