Given the following relations and referential integrity rules, draw an ER diagram on the following blank page. Make assumptions where necessary but be sure to list any assumptions made. Show each assumption with a capital A inside a circle. Assumptions cannot be made in contradiction to the given relations and foreign key constraints. (Primary keys are underlined, foreign keys are bold).

TROLL(TrollName, FootColor, BeardLength, TrollType, SupervisorName)

Foreign Key SupervisorName references Troll(TrollName)

Null Allowed, On Delete Set Null

BRIDGE(BridgeID, Name, Length, Toll, TrollName)

Foreign Key TrollName references Troll(TrollName)

Null Allowed, On Delete Restrict

ROUTE(BridgeID, CityName, Distance, RoadCondition)

Foreign Key BridgeID references Bridge(BridgeID)

Not Null, On Delete Restrict

Foreign Key CityName references City(CityName)

Not Null, On Delete Restrict

CITY(CityID, Population, OdorIndex)

COUNCIL(Cityname, ChampName, ManagerID, HappyLevel, CityRatio, ChampRatio, MgrRatio)

Foreign Key CityName references City(CityName)

Not Null, On Delete Restrict

Foreign Key ChampName references Champion(ChampName)

Not Null, On Delete Restrict

Foreign Key ManagerID references Manager(ManagerID)

Not Null, On Delete Restrict

CHAMPION(ChampName, WSBI, Trope, HorseName)

MANAGER(ManagerID, CMSL, FirstName, LastName, Street, City, Sector)

SKILLSET(SkillSetID, ManagerID, SkillID, DateLearned, Location, Payment)

Foreign Key ManagerID references Manager(ManagerID)

Not Null, On Delete Restrict

Foreign Key SkillID references Skill(SkillID)

Not Null, On Delete Restrict

SKILL(SkillID, RetailCost, MasteryHours)