What does the red dot in sql database means

Question

In tables of sql what does the red dot means

Answer 1

???

Answer 2

Coding in color?

Answer 3

it means... "this cell has changed.
the change has not been committed to the database.
the original data is NULL. "

it happens when you choice not NULL column cells and when you enter the values in sql table, give you the alert that u must fill up all column cells