I constantly get this error message and have googled countless amounts of times and tried fixing stuff but nothing has worked.

New Student Table Student Advisory New Advisor Table Field Name Data Type Student ID Large Number Advisor Name Short Text Student Name Short Text HW #1 Number HW #2 Number Midterm Number Microsoft Access X Index or primary key cannot contain a Null value. OK Help Field Properties General Lookup Format Decimal Places Auto Input Mask Caption Default Value 0 Validation Rule Validation Text Required Yes Indexed Yes (Duplicates OK) Text Align General