Mysql EntityFramework error The value for column 'IsPrimaryKey' in table 'tablename' is DBNull 발생때.

만약  아래와 같은 에러가 뜨면

Unable to generate the model because of the following exception: 'System.Data.StrongTypingException: The value for column 'IsPrimaryKey' in table '무슨무슨테이블' is DBNull. ---> System.InvalidCastException: 

Mysql comment 창 열고 아래 코드 실행

1. Open Services (services.msc) and restart MySQL57 service.
2. Execute the following commands in MySQL.
   use <<database name>>;
   set global optimizer_switch='derived_merge=OFF';
3. Update the .edmx.

p.s Update the .edmx. 는 안해도 되는듯??

그리고 다시 위에 5번부터 다시하면됨!