When inserting data, what are the problems that can occur if you dont enter the data in the same order as the columns?

Why do you get an error if you dont enter data for all the columns?

When you update a table what is best practice to do prior to updating the data? What business issues may occur if you dont use a qualifier, for example, a WHERE keyword when updating data.

When you update a table, what is best practice to do prior to deleting the data? What are possible business concerns you might have if you dont use the WHERE keyword when deleting data? What reasons are insert, update, and delete commands so vitality important from a business standpoint?