Database Creation with ER Model

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Questions and Answers

What SQL command is used to add data to the Students table?

INSERT INTO Students (correct)

SELECT * FROM Students

UPDATE Students

DELETE FROM Students

Which column from the Enrollments table indicates when a student enrolled in a course?

course_name

enrollment_date (correct)

student_id

course_id

What will the following query return? 'SELECT Courses.course_name FROM Courses JOIN Enrollments ON Courses.course_id = Enrollments.course_id WHERE Enrollments.student_id = 1;'

The total number of courses available

Names of all students enrolled in all courses

Course names that student_id 1 is enrolled in (correct)

Course names along with their student IDs

How can one count the number of students enrolled in each course according to the provided SQL statement?

By using COUNT() with a GROUP BY clause Signup and view all the answers

Why is designing an ER model beneficial for creating a relational database?

It provides a visual representation of data relationships Signup and view all the answers

What is the purpose of the JOIN clause in SQL?

To combine rows from two or more tables based on related columns Signup and view all the answers

When forming the statement to show all courses taken by 'Tom Green', what name should be used in the WHERE clause?

'Tom Green' Signup and view all the answers

What type of SQL statement is used to view data from the Students table?

SELECT Signup and view all the answers

What is the purpose of the entity 'Enrollments' in the university database?

To manage student enrollments in courses Signup and view all the answers

Which SQL command is used to create the new database 'UniversityDB'?

CREATE DATABASE UniversityDB; Signup and view all the answers

How is the relationship between 'Students' and 'Courses' defined in the ER diagram?

A Student can enroll in multiple Courses Signup and view all the answers

What type of attribute is 'student_id' in the Students table?

INT AUTO_INCREMENT PRIMARY KEY Signup and view all the answers

Which command is used to change the active database to 'UniversityDB' after creation?

USE UniversityDB; Signup and view all the answers

What is the purpose of defining foreign keys in the Enrollments table?

To link enrollment records to both Students and Courses Signup and view all the answers

Which attribute in the Courses table signifies the academic load of a course?

course_credits Signup and view all the answers

In the context of the ER diagram, what does the 'AUTO_INCREMENT' feature do for the student_id?

Ensures the student_id is a unique numeric value for each student Signup and view all the answers

Study Notes

Overview of Entity-Relationship (ER) Model and Database Creation

The exercise involves designing an ER diagram for a university database and translating it into a MySQL relational schema.
Objectives include practicing database design and understanding the connection between ER models and physical databases.

ER Diagram Design

Key entities in the ER model:
- Students: Attributes include student_id, student_name, student_email.
- Courses: Attributes include course_id, course_name, course_credits.
- Enrollments: Attributes include enrollment_id, student_id, course_id, enrollment_date.
Defined relationships:
- A Student can enroll in multiple Courses.
- A Course can have multiple Students.

Creating the Database

Command to establish a new database:
- CREATE DATABASE UniversityDB;
- Use the database with USE UniversityDB;

Table Definitions

Students Table:
- Structure defined using SQL, specifying structure and primary key:
  - CREATE TABLE Students (...);
Courses Table:
- Similarly defined with attributes and primary key:
  - CREATE TABLE Courses (...);
Enrollments Table:
- Contains foreign keys linking to both Students and Courses:
  - CREATE TABLE Enrollments (...);

Inserting Sample Data

Students:
- Insertion command for multiple student records:
  - Sample names and emails provided.
Courses:
- Insertion command for course records detailing course names and credits.
Enrollments:
- Insertion command to establish student enrollments in specific courses with dates.

Query Execution

SQL queries provided to:
- List all students enrolled in a specific course.
- Show all courses taken by a particular student.
- Count the number of students enrolled in each course.

Reflection on ER Modeling

Designing an ER model enhances understanding of how entities interact, leading to a well-structured database.
Aids in identifying relationships and attributes, ensuring efficient database design and data integrity.

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Description

This quiz focuses on designing an Entity-Relationship (ER) model for a university database and converting it into a MySQL relational schema. Participants will explore key entities such as Students and Courses, and their relationships, as well as the commands used in SQL for database creation.