It's not saving into the database definitely because the field 'column_name' (and maybe some others) is checked as "NOT NULL". It means that the value of that field must be something other than NULL (NULL - no data at all)
Marking fields as not null is usually a great way to ensure that some data will always be present in the field. Depending on your needs, you can also mark it as NULL so it will never throw an error and will save into DB without the need for anything to be inserted into a specified field.
It means you have 2 options:
Mark your field as NULL (first check if your field is required to have some value or not).
ALTER TABLE your_table
CHANGE COLUMN your_field your_field VARCHAR(250) NULL;
Add a default value to the field so if no data is provided on insert, it will put something you defined.
For example:
ALTER TABLE your_table CHANGE COLUMN your_field your_field VARCHAR(250) NOT NULL DEFAULT 'some_default_value';
And of course, match your field type to the field you are going to change.
