Q4. ii)Examine the given relations of a University Database Management System: Student (Reg_no, sName, phone, email_id, D_id) Department (D_id, D_name, address) Course (C_id, C_name, D_id, credits) Result (C_id, Reg_no, Grade) Submit a SQL query to retrieve the names, email addresses, and grades of the students from the CSE department who choose Java Programming. Showcase the sequential steps involved in query optimization.?

Question

Q4. ii)Examine the given relations of a University Database Management System:  Student (Reg_no, sName, phone, email_id, D_id)  Department (D_id, D_name, address)  Course (C_id, C_name, D_id, credits)  Result (C_id, Reg_no, Grade)  Submit a SQL query to retrieve the names, email addresses, and grades of the students from the CSE department who choose Java Programming. Showcase the sequential steps involved in query optimization.?

Answer

SQL Query:
sql
SELECT sName, email_id, Grade
FROM Student s
JOIN Result r ON s.Reg_no = r.Reg_no
JOIN Course c ON r.C_id = c.C_id
WHERE c.C_name = 'Java Programming'
AND s.D_id = (SELECT D_id FROM Department WHERE D_name = 'CSE');

Query Optimization Steps:
1. Use Indexes: Ensure that the columns used in the WHERE clause, JOIN conditions, and ORDER BY clause are indexed to improve query performance.
2. Reduce Data Retrieval: Only retrieve the necessary columns in the SELECT statement to minimize data transfer between the database and application.
3. Optimize JOINs: Use INNER JOIN instead of other types of JOINs if only matching rows are needed. Also, consider the order of tables in the JOIN clause based on the size of the tables.
4. Use EXISTS instead of IN: Replace IN with EXISTS for better performance, especially when dealing with subqueries.
5. Limit Results: Use LIMIT or TOP to restrict the number of rows returned if the query is expected to return a large result set.
6. Avoid Wildcard Characters: Minimize the use of wildcard characters in the WHERE clause as they can slow down query execution.
7. Analyze Query Execution Plan: Use tools like EXPLAIN to analyze the query execution plan and identify any potential bottlenecks.
By following these query optimization steps, you can enhance the performance of your SQL query to retrieve the names, email addresses, and grades of students from the CSE department who choose Java Programming efficiently.

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