1.Dormitory management system at a campus
A.create entity and their attributes
B.identify the degree of their relationship
C.identity their cardinalities
D.constraints
E.ER Diagram
A. Entities and their attributes:
1. Dormitory:
- Dormitory_ID (primary key)
- Dormitory_Name
- Address
- Capacity
2. Room:
- Room_ID (primary key)
- Dormitory_ID (foreign key)
- Room_Number
- Capacity
3. Student:
- Student_ID (primary key)
- Room_ID (foreign key)
- Name
- Gender
- Contact_Number
B. Degree of Relationship:
- Dormitory and Room have a one-to-many relationship. Each dormitory can have multiple rooms, but each room belongs to only one dormitory.
- Room and Student have a one-to-many relationship. Each room can accommodate multiple students, but each student belongs to only one room.
C. Cardinalities:
- Dormitory (1) <-------- (1 to many) Room
- Room (1) <-------- (1 to many) Student
D. Constraints:
- Dormitory_ID in Dormitory is unique and cannot be null.
- Dormitory_Name in Dormitory cannot be null.
- Address in Dormitory cannot be null.
- Capacity in Dormitory must be a positive integer.
- Room_ID in Room is unique and cannot be null.
- Dormitory_ID in Room is a foreign key referencing Dormitory(Dormitory_ID).
- Room_Number in Room cannot be null.
- Capacity in Room must be a positive integer.
- Student_ID in Student is unique and cannot be null.
- Room_ID in Student is a foreign key referencing Room(Room_ID).
- Name in Student cannot be null.
- Gender in Student cannot be null.
- Contact_Number in Student cannot be null.
E. ER Diagram:
```
+-----------+ +---------+
| Dormitory | | Room |
+-----------+ +---------+
|Dormitory_ID+----+ |Room_ID |
|Dormitory_Na| | |Dormitory|
| me +--+ | |Room_Num |
| Address | | | | ber |
| Capacity | | | | Capacity|
+-----------+ | | +---------+
|
|
|
|
+--------+-------+
| Student |
+----------------+
| Student_ID |
| Room_ID |
| Name |
| Gender |
| Contact_Number |
+----------------+
```
A. Entities and their attributes for the Dormitory Management System at a campus could include:
1. Campus:
- Campus ID (Primary Key)
- Campus Name
- Campus Location
2. Dormitory:
- Dormitory ID (Primary Key)
- Dormitory Name
- Dormitory Capacity
3. Resident:
- Resident ID (Primary Key)
- Resident Name
- Resident Gender
- Resident Contact Number
4. Room:
- Room Number (Primary Key)
- Room Capacity
- Dormitory ID (Foreign Key)
5. Bed:
- Bed Number (Primary Key)
- Bed Status (e.g., occupied or vacant)
- Room Number (Foreign Key)
B. The degree of relationships is as follows:
- One Campus can have multiple Dormitories.
- One Dormitory can have multiple Residents.
- One Dormitory can have multiple Rooms.
- One Room can have multiple Beds.
C. The cardinalities indicate the number of entity instances that can be associated with another entity instance in a relationship. In this context:
- One Campus can have zero or multiple Dormitories.
- One Dormitory can have zero or multiple Residents.
- One Dormitory can have zero or multiple Rooms.
- One Room can have zero or multiple Beds.
D. Constraints for the Dormitory Management System may include:
- Dormitory Capacity should not exceed the maximum capacity limit defined by the campus.
- Resident ID should be unique for each resident.
- Room Number should be unique within a dormitory.
- Bed Number should be unique within a room.
- Dormitory ID and Room Number in Beds table should match with the corresponding entities.
E. The ER Diagram can be drawn using various notations. In a basic Chen's notation, the diagram would display the entities (Campus, Dormitory, Resident, Room, Bed) and their relationships (one-to-one, one-to-many, many-to-many) using appropriate connectors and cardinality indicators.
To create an entity-attribute diagram for a dormitory management system at a campus, follow these steps:
A. Create Entities and Their Attributes:
1. Dormitory:
- Dormitory ID
- Dormitory Name
- Dormitory Capacity
2. Room:
- Room ID
- Room Number
- Room Capacity
3. Student:
- Student ID
- Student Name
- Student Contact
4. Floor:
- Floor ID
- Floor Number
B. Identify the Degree of Their Relationships:
1. Dormitory has a One-to-Many relationship with Room (one dormitory can have multiple rooms).
2. Room has a One-to-Many relationship with Student (one room can accommodate multiple students).
3. Dormitory has a One-to-Many relationship with Floor (one dormitory can have multiple floors).
C. Identify Their Cardinalities:
1. Dormitory to Room: One Dormitory (1) can have multiple Rooms (M).
2. Room to Student: One Room (1) can have multiple Students (M).
3. Dormitory to Floor: One Dormitory (1) can have multiple Floors (M).
D. Define Constraints:
1. Each student can only be assigned to one room at a time.
2. The capacity of a room should not be exceeded.
3. Each dormitory should have at least one floor.
E. Draw the ER Diagram:
Using a tool like Lucidchart or any other ER diagramming software, create an ER diagram that represents the entities, relationships, and attributes. You can represent the dormitory as an entity, the room and student as weak entities (connected to the dormitory as owner), and floor as a separate entity. Use appropriate notation and symbols to define the relationships and cardinalities between entities.
Remember, the steps above are a general guideline to help you create an entity-attribute diagram for a dormitory management system. The specific details and attributes may vary based on the requirements and constraints of your particular scenario.