Allowing invalid data to be entered into the database ensures that the database and the data available will become less valuable and harder for the user to use.
form validation can be implemented in a number of different ways.
Form validation helps us achieve these goals — this article tells you what you need to know.
This is called form validation — when you enter data the web application checks it to see if it is correct.
Practically no one uses Excel to update databases directly.
I think the reason is because we think of Excel as a tool that end users can do whatever they want to with and updating databases requires discipline.