Top down bottom up approach

what does the instructor means by saying to follow top down and bottom up approach to normalise the table?

Hey @kani001

I expect you mean top-down design vs bottom-up design - normalization being just one aspect of the methods and principles you would use to complete a database design.
There are two approaches for developing any database, the top-down method and the bottom-up method.
Top-down means you start with a set of requirements. Usually you begin by identifying the types of things that you need to represent data about and then identify the attributes of those things, which will become attributes in tables.

Bottom-up design means you are given some kind of data structures to start with, e.g. a list of attributes or tables and attributes which you need to incorporate into a design. Typically this might happen where you have an existing database or data source, as is common in business intelligence or data integration projects.
If those aren’t discussed in the videos then please refer to this :
(1)
(2)