I have a MSSQL database where I have a customers table which has 35 columns (tried to make data types as good as possible for performance issues)
Now I need to add 30 more fields to hold extra info about customers (a questionnaire results)
My question is should I design so that the repeating values are written repetaedly to columns?
Should I make supporting tables with Primary key info entered to customers table's respective fields as foreign keys
I know the first approach is not effective in means of performance, however I am concerned about 30 odd foreign keys, too.
Which way sould I follow? Which better in performance?