Xinyi+Wu

Player (P_name,P_ID) PK (P_ID) no attributes should be NULL

Game (version, runtime, G_ID, score, G_date, P_ID) PK( G_ID) FK(P_ID) references Player (P_ID) no attributes should be NULL

Game piece ( GP_name, Deadtime, Buildtime, GP_ID) PK( GP_ID) FK(G_ID) references Game (G_ID) no attributes should be NULL

Ship (GP_ID, Ship_ID) PK(ship_ID) FK (GP_ID) references GAMEPIECE ( GP_ID) no attributes should be NULL

Enemy( GP_ID, Enemy_ID, level) Pk( Enemy_ID) FK (GP_ID) references GAMEPIECE ( GP_ID) no attributes should be NULL

Weapon ( GP_ID, Weapon_ID, Ship_ID, Enemy_ID PK( weapon_ID)  Fk(GP_ID) references GAMEPIECE ( GP_ID)  Fk(SHIp_ID) references ship(SHIP_ID)  Fk(enemy_ID) references enemy(enemy_ID) no attributes should be NULL

Missle( dmg, missle_ID,GP_ID) Pk(Missle_ID) FK (GP_ID) references GAMEPIECE ( GP_ID) no attributes should be NULL

Hit( MIssle_ID, Enemy_ID, Ship_ID, health_OF_SHIP, HIT_TIME) PK (missle_ID) Fk(missle_ID) references missle(MISSLE_ID) no attributes should be NULL