The Database Solution Technology Essay Research Paper (Essay Sample)

DATABASE MANAGEMENT SYSTEMS
Assignment 3
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CS610AH1: Database Management Systems
Assignment 3
Part 1(Entity Relationship Diagrams)
1 The entity-relationship diagram represents a model of dorm management and room allocation system in a school setup. It has three entities Dorm, Student, and Room. Entity dorm attributes are Dname, which is the primary key, numRooms, and address. Entity Room attributes are RoomNo, bunkBeds, and sharedBathroom. Entity Student attributes are Sid, which is the primary key, name, and phone. Dorm and Room are strong entities, while Room is a weak entity. The relationship constraint between Dorm and Room is one-to-many. Therefore, a dorm can have many. Room can only belong to one Dorm. The relationship constraint between Room and Student is one-to-many with a minimum cardinality of zero (optional participation), whereby a room can have 0, 1, or 2 students. A student Resides in a Room.
Room entity has no primary key because it is a weak entity; it cannot be identified by it is own attributes alone.