Notice we had to modify the field before we removed it’s Primary Key Property
Primary Key Fields should be Auto Increment, Only Key Fields can be Auto Increment, So If you want to remove the Primary Key Property you must first remove the Auto Increment Property
Redefined the field from INT(5) AUTO INCREMENT to just INT(5)
Removal of the PRIMARY KEY Property
Notice that removal of the AUTO INCREMENT uses a MODIFY command and removal of the PRIMARY KEY uses a DROP command
Also Notice in the DROP command I do not have to identify the Primary Key by name