Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class Main {
    // JDBC driver name and database URL
    static final String JDBC_DRIVER = "org.hsqldb.jdbcDriver";
    static final String DB_URL = "jdbc:hsqldb:mem:db_file";

    // Database credentials
    static final String USER = "sa";
    static final String PASS = "";

    public static void main(String[] args) {
        Connection conn = null;
        Statement stmt = null;
        try {
            // STEP 2: Register JDBC driver
            Class.forName(JDBC_DRIVER);

            // STEP 3: Open a connection
            System.out.println("Connecting to database...");
            conn = DriverManager.getConnection(DB_URL, USER, PASS);

            // STEP 4: Execute a query
            System.out.println("Creating statement...");
            stmt = conn.createStatement();
            String sql;
            sql = "SELECT id, first, last, age FROM Employees";
            stmt.executeUpdate(
                    "CREATE TABLE Employees ( id INTEGER IDENTITY, first VARCHAR(256),  last VARCHAR(256),age INTEGER)");
            stmt.executeUpdate("INSERT INTO Employees VALUES(1,'Jack','Smith', 100)");

            ResultSet rs = stmt.executeQuery(sql);

            // STEP 5: Extract data from result set
            while (rs.next()) {
                // Retrieve by column name
                int id = rs.getInt("id");
                int age = rs.getInt("age");
                String first = rs.getString("first");
                String last = rs.getString("last");

                System.out.print("ID: " + id);
                System.out.print(", Age: " + age);
                System.out.print(", First: " + first);
                System.out.println(", Last: " + last);
            }
            // STEP 6: Clean-up environment
            rs.close();
            stmt.close();
            conn.close();
        } catch (SQLException se) {
            se.printStackTrace();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            // finally block used to close resources
            try {
                if (stmt != null)
                    stmt.close();
            } catch (SQLException se2) {
            }
            try {
                if (conn != null)
                    conn.close();
            } catch (SQLException se) {
                se.printStackTrace();
            }
        }
        System.out.println("Goodbye!");
    }
}