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  • Ashish Sikarwar thinks this is interesting:

1. All columns must be atomic—that is, each column should represent one value

2. All rows of a table must contain the same number of values—no arrays

From

Cover of Exam Ref 70-762 Developing SQL Databases, First Edition

Note

https://sqlspellbook.com/2015/02/20/a-practical-definition-for-first-normal-form-1nf/