SQL with Java — Build School Applications with JDBC

A school application needs a class report based on a user-selected class without treating that input as SQL syntax.

JDBC is Java’s database access API. A suitable database driver supplies connections, statements and result sets for the selected engine.

Use PreparedStatement with a question-mark value placeholder, bind values using the appropriate setter, then execute and read ResultSet rows. JDBC parameter indexes start at one. Try-with-resources closes connections, statements and result sets that are included in its resource declaration.

Related concepts: Prevent SQL Injection and Transactions and Connect with JDBC and ODBC.

JDBC (Java Database Connectivity) is a Java API that allows you to connect and interact with SQL databases from Java code. It supports SELECT, INSERT, UPDATE, DELETE, and more — all with Java objects.

• JDK installed (Java 8+ recommended)
• MySQL Server (or SQLite for lightweight apps)
• MySQL JDBC driver (Connector/J)

SQL · portable concepts; preserved examples identify their engine

CREATE DATABASE school;
USE school;

CREATE TABLE students (
  roll_no INT PRIMARY KEY,
  name VARCHAR(50),
  class VARCHAR(10),
  city VARCHAR(30)
);

INSERT INTO students VALUES
(1, 'Aarav', '10A', 'Pune'),
(2, 'Diya', '9B', 'Hyderabad');

Java · JDBC

import java.sql.*;

public class StudentDatabase {
    public static void main(String[] args) {
        String url = "jdbc:mysql://localhost:3306/school";
        String user = "root";
        String password = "your_password";

        try {
            // Step 1: Load driver (optional in modern Java)
            Class.forName("com.mysql.cj.jdbc.Driver");

            // Step 2: Create connection
            Connection conn = DriverManager.getConnection(url, user, password);

            // Step 3: Create statement
            Statement stmt = conn.createStatement();

            // Step 4: Execute query
            ResultSet rs = stmt.executeQuery("SELECT * FROM students");

            // Step 5: Process results
            while (rs.next()) {
                int roll = rs.getInt("roll_no");
                String name = rs.getString("name");
                String studentClass = rs.getString("class");
                String city = rs.getString("city");

                System.out.println(roll + " | " + name + " | " + studentClass + " | " + city);
            }

            // Step 6: Close connection
            rs.close();
            stmt.close();
            conn.close();

        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

1 | Aarav | 10A | Pune  
2 | Diya  | 9B  | Hyderabad

Java · JDBC

String insertSQL = "INSERT INTO students (roll_no, name, class, city) VALUES (?, ?, ?, ?)";
PreparedStatement ps = conn.prepareStatement(insertSQL);
ps.setInt(1, 3);
ps.setString(2, "Sneha");
ps.setString(3, "9A");
ps.setString(4, "Mumbai");
ps.executeUpdate();

• Always close Connection, Statement, and ResultSet
• Use PreparedStatement to avoid SQL Injection
• Handle exceptions with try-with-resources (Java 7+)
• Validate user input before executing queries

• Building a Java-based student record management system
• Creating admin dashboards for principals
• Generating attendance and fee reports dynamically
• Automating admissions using Java GUIs + MySQL

A driver must be installed and compatible with the server. Closing resources is not a substitute for choosing transaction boundaries when auto-commit is disabled. Keep credentials in configuration and verify the driver’s TLS settings rather than copying insecure connection flags.

Design a JDBC statement with a bound class value, then predict the two returned names for 10A.

This practice uses a separate, fresh fixture named practice_students. It does not continue the changing table state of the earlier examples.

SQL · create only these practice tables in a disposable database:

CREATE TABLE practice_students (roll_no INTEGER PRIMARY KEY, name VARCHAR(50), class VARCHAR(10), marks INTEGER, city VARCHAR(30));
INSERT INTO practice_students VALUES
(1, 'Aarav', '10A', 85, 'Pune'),
(2, 'Diya', '9B', 70, 'Chennai'),
(3, 'Sneha', '10A', 85, 'Pune');

This practice uses a separate, fresh fixture named practice_students. It does not continue the changing table state of the earlier examples.

SQL · create only these practice tables in a disposable database:

CREATE TABLE practice_students (roll_no INTEGER PRIMARY KEY, name VARCHAR(50), class VARCHAR(10), marks INTEGER, city VARCHAR(30));
INSERT INTO practice_students VALUES
(1, 'Aarav', '10A', 85, 'Pune'),
(2, 'Diya', '9B', 70, 'Chennai'),
(3, 'Sneha', '10A', 85, 'Pune');

SQL · this practice variation runs with SQLite 3; the preserved examples retain their stated dialect

Bind the value "10A" through the driver’s parameter API. The question mark is a parameter marker, not literal SQL text to replace with string concatenation.

SELECT name FROM practice_students WHERE class = ? ORDER BY roll_no;

The SQL-level behavior is verified with the practice fixture. In Java, setString(1, "10A") binds the first parameter; the preserved JDBC examples require the specified driver and live server.

JDBC is Java’s database access API. A suitable database driver supplies connections, statements and result sets for the selected engine.

The SQL-level behavior is verified with the practice fixture. In Java, setString(1, "10A") binds the first parameter; the preserved JDBC examples require the specified driver and live server.

Continue your understanding with Prevent SQL Injection and Transactions and Connect with JDBC and ODBC.

Source for the engine-specific behavior: MySQL Connector/J documentation.