What is the default behavior of columns in the Top Down approach regarding nullability?

In the Top Down approach, the design philosophy often emphasizes flexibility and adaptability to business needs. This means that most columns in the initial design are not mandated to be required. It allows for optional data entry, which can be particularly useful in scenarios where not all fields need to be populated for a record to be meaningful.

Having non-required fields promotes a more user-friendly experience, as it enables users to submit incomplete data when full information is not available, aligning closely with agile development practices. Therefore, the default behavior leaning towards non-required columns supports iterative development, allowing enhancements and changes to be made as business requirements evolve.

In contrast, the notion that all columns or most columns should be required by default would impose constraints that could hinder flexibility in initial design stages. The option suggesting no effect on nullability is misleading, as there is indeed a default stance concerning column requirements, significantly influencing data integrity and user input expectations.