Tiny College Course And Class Segment
Tiny College Course And Class Segmentvsdtexttablecoursepkcrs Code
Tiny College Course And Class Segmentvsdtexttablecoursepkcrs Code
Generate an Entity-Relationship (ER) diagram and corresponding database schema based on the provided course, class, and enrollment data, along with the specified business rules. Your task involves identifying entities, their attributes, primary keys, foreign keys, and the relationships among these entities, ensuring the constraints and rules are correctly modeled.
Instructions:
- Analyze the provided data table descriptions, including COURSE, CLASS, STUDENT, and INSTRUCTOR entities, their attributes, and business rules.
- Design an ER diagram that reflects the entities, their attributes, primary keys, foreign keys, and relationships.
- Derive a normalized relational schema from your ER diagram, explicitly specifying primary keys, foreign keys, and relationship constraints.
- Ensure the schema respects all business rules, including the cardinality and optionality constraints, such as:
- One COURSE may generate many CLASSes, or none.
- Each CLASS is generated by exactly one COURSE.
- Many STUDENTs may enroll in many CLASSes.
- No classes are scheduled on Sundays.
- Classes occur only between 6:30 a.m. and 10:00 p.m.
- Address specific entity details like GRADUATE, UNDERGRADUATE, and INSTRUCTOR, including their relationship to STUDENT.
- Incorporate enrollments, including many-to-many relationships between STUDENT and CLASS.
- Present your ER diagram with clear notation and your relational schema with proper normalization.
Note: Focus on the logical design that captures all business rules and relationships, suitable for implementation in a relational database system.
Paper For Above instruction
The task of designing a comprehensive database schema for a small college involves understanding the core entities, their attributes, and the relationships among them, guided by business rules and constraints. Based on the provided data and rules, this paper presents an ER diagram and relational schema for the college's course, class, student, instructor, and enrollment data, ensuring adherence to all specified business conditions.
Overview of Entities and Attributes
The primary entities involved in this college database are Course, Class, Student, Instructor, and Enrollment. Each entity has specific attributes, with primary keys to uniquely identify each record.
- Course: Represents the academic courses offered by the college.
- Attributes: CRS_CODE (PK), CRS_TITLE, CRS_DESCRIPTION, CRS_CREDITS.
- Class: Represents individual class sections for courses.
- Attributes: CLASS_PK (PK), CLASS_CODE, CLASS_SECTION, CLASS_TIME, CRS_CODE (FK).
- Student: Represents college students, with distinctions for undergraduate and graduate students.
- Attributes: STUD_ID (PK), STUD_FNAME, STUD_LNAME, STUD_TYPE.
- Instructor: Represents instructors who teach classes.
- Attributes: INST_ID (PK), INST_FNAME, INST_LNAME, INST_TITLE.
- Enrollment: Represents the enrollment relationship between students and classes.
- Attributes: STUD_ID (FK), CLASS_PK (FK).
In addition, the Graduate and Undergraduate entities are specialized types of Student, with specific attributes like GRAD_THESIS and UND_HOURS. These can be modeled as subclasses.
Relationships and Business Rules
The relationships based on the business rules are as follows:
- Course to Class: One-to-many (one course can generate many classes, but some courses may not generate classes). This is a zero-or-more to one relationship, captured by CRS_CODE as a foreign key in Class.
- Class to Course: Each class is generated by exactly one course.
- Student to Class: Many students can enroll in many classes, indicating a many-to-many relationship, resolved through an Enrollment associative entity.
- Instructor to Class: Each class may have an instructor, establishing a one-to-many relationship if each class has one instructor.
- Time Constraints and Scheduling Rules: Classes are scheduled only between 6:30 a.m. and 10:00 p.m., and not on Sundays. These constraints can be enforced through scheduling attributes and validation rules, not directly modeled in the ER diagram but considered in implementation.
ER Diagram Description
The ER diagram includes entities with their attributes, connected through relationships:
- Course (CRS_CODE, CRS_TITLE, CRS_DESCRIPTION, CRS_CREDITS)
Connected to Class via a "generates" relationship.
- Class (CLASS_PK, CLASS_CODE, CLASS_SECTION, CLASS_TIME, CRS_CODE)
Connected back to Course and to Instructor (if applicable).
Also connected to Enrollment for student registration.
- Student (STUD_ID, STUD_FNAME, STUD_LNAME, STUD_TYPE)
Specialized into Graduate (with GRAD_THESIS) and Undergraduate (with UND_HOURS).
- Instructor (INST_ID, INST_FNAME, INST_LNAME, INST_TITLE)
Connected to Class to denote teaching assignments.
- Enrollment (STUD_ID, CLASS_PK): Resolves many-to-many between Student and Class.
Relational Schema
Based on the ER diagram, the relational schema includes the following tables:
```sql
-- Course Table
CREATE TABLE Course (
CRS_CODE VARCHAR(10) PRIMARY KEY,
CRS_TITLE VARCHAR(100),
CRS_DESCRIPTION TEXT,
CRS_CREDITS DECIMAL(3,1)
);
-- Class Table
CREATE TABLE Class (
CLASS_PK INT PRIMARY KEY,
CLASS_CODE VARCHAR(10),
CLASS_SECTION VARCHAR(10),
CLASS_TIME TIME,
CRS_CODE VARCHAR(10),
FOREIGN KEY (CRS_CODE) REFERENCES Course(CRS_CODE)
);
-- Student Table
CREATE TABLE Student (
STUD_ID INT PRIMARY KEY,
STUD_FNAME VARCHAR(50),
STUD_LNAME VARCHAR(50),
STUD_TYPE VARCHAR(20) -- 'Undergraduate' or 'Graduate'
);
-- Graduate Student Details
CREATE TABLE Graduate (
STUD_ID INT PRIMARY KEY,
GRAD_THESIS TEXT,
FOREIGN KEY (STUD_ID) REFERENCES Student(STUD_ID)
);
-- Undergraduate Student Details
CREATE TABLE Undergraduate (
STUD_ID INT PRIMARY KEY,
UND_HOURS INT,
FOREIGN KEY (STUD_ID) REFERENCES Student(STUD_ID)
);
-- Instructor Table
CREATE TABLE Instructor (
INST_ID INT PRIMARY KEY,
INST_FNAME VARCHAR(50),
INST_LNAME VARCHAR(50),
INST_TITLE VARCHAR(50)
);
-- Class Instructor Assignment
CREATE TABLE ClassInstructor (
CLASS_PK INT,
INST_ID INT,
PRIMARY KEY (CLASS_PK, INST_ID),
FOREIGN KEY (CLASS_PK) REFERENCES Class(CLASS_PK),
FOREIGN KEY (INST_ID) REFERENCES Instructor(INST_ID)
);
-- Enrollment Table (Many-to-Many)
CREATE TABLE Enrollment (
STUD_ID INT,
CLASS_PK INT,
PRIMARY KEY (STUD_ID, CLASS_PK),
FOREIGN KEY (STUD_ID) REFERENCES Student(STUD_ID),
FOREIGN KEY (CLASS_PK) REFERENCES Class(CLASS_PK)
);
```
Validation and Constraints
The schema enforces the following business rules:
- Each class is associated with exactly one course, but courses may not have classes.
- Students can enroll in multiple classes, and each class can have multiple students, enforced via the Enrollment table.
- Classes are scheduled with time constraints; though not directly modeled in the schema, application-level validation can enforce times between 6:30 a.m. and 10:00 p.m., excluding Sundays.
- Instructors are assigned to classes via a linking table, allowing one or many instructors per class, depending on policy.
Conclusion
The designed ER diagram and relational schema effectively model the college system, fulfilling all specified business rules and constraints. The normalization ensures data integrity, while the foreign key relationships maintain referential integrity. Future implementation can incorporate additional constraints such as scheduling and time restrictions through application logic or database triggers, ensuring classes are scheduled appropriately and in compliance with business policies.
References
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- Journal of Information Science, 44(3), 347-359.
- Database Management Systems (3rd Edition). McGraw-Hill.
- Database Systems: The Complete Book (2nd Edition). Prentice Hall.
- Lecture Notes in Computer Science. Springer.
- ACM Transactions on Database Systems, 1(1), 9-36.
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