<a href="https://objectstorage.us-phoenix-1.oraclecloud.com/p/BqK85Rn1zA5MP0vYiqbAdPgs7Z6OmMxw8SD3WCFVm5kY8uReidZ1KPIKkgJ1hCkG/n/axciphqpnohg/b/forums-legacy/o/uploads/BVN4TMSFOHAZ/er-diag.jpg" alt="er diag.jpg type="image/jpeg">er diag.jpg</a> (50.25 KB)Attach the database ER diagram , as you can see , there are symbols in front of the keys , eg. P , F , FK, key , red asterisk , two green lines , U etc , just would like to know what this symbols represent , what is its function ? is there any documnet on web explains it that I can refer to ?
thanks