there were a lot of answers related to this, but I couldn\'t find useful information. I\'m trying to connect to the database and insert user\'s entered values into it, but I
The error seems quite clear. You have a column in the table that cannot take on a NULL value.
I would speculate that it is not one of the column where you are explicitly providing a value (name, surname, employment_date). You need to look at the definition of the table and look for another column defined as NOT NULL (or perhaps PRIMARY KEY with no default value).