**Course Title:** Comprehensive Java Programming: From Basics to Advanced Concepts **Section Title:** Database Connectivity with JDBC **Topic:** Introduction to JDBC (Java Database Connectivity) **Introduction** Java Database Connectivity (JDBC) is a Java-based API that enables interaction between Java applications and relational databases. It allows developers to write platform-independent Java code to access, manipulate, and manage data stored in various relational databases. In this topic, we will delve into the basics of JDBC, its architecture, and the benefits it offers for database connectivity. **What is JDBC?** JDBC is a set of Java classes and interfaces that provide a standard way to connect to relational databases. It was first introduced in 1997 as part of the Java Standard Edition (Java SE) and has since become a widely-used technology for database connectivity. JDBC provides a common interface for various databases, allowing developers to write database-agnostic code that can connect to different databases. **JDBC Architecture** The JDBC architecture consists of two layers: 1. **JDBC API**: This is the Java API that provides a set of classes and interfaces for interacting with databases. The JDBC API is divided into two packages: `java.sql` and `javax.sql`. 2. **JDBC Driver**: This is a database-specific driver that converts JDBC API calls into native database calls. JDBC drivers are typically provided by the database vendor or a third-party vendor. **Key Components of JDBC** 1. **Connection**: Represents a connection to a database. You can obtain a connection using the `DriverManager.getConnection()` method. 2. **Statement**: Represents a SQL statement that can be executed on the database. There are three types of statements in JDBC: `Statement`, `PreparedStatement`, and `CallableStatement`. 3. **ResultSet**: Represents the result of a SQL query. You can use the `ResultSet` object to retrieve data from the database. 4. **SQLException**: Represents an exception that occurs during database operations. **Types of JDBC Drivers** There are four types of JDBC drivers: 1. **Type 1 Driver**: Uses the ODBC (Open Database Connectivity) API to connect to databases. Not commonly used. 2. **Type 2 Driver**: Converts JDBC calls into native database calls using a native library. Requires native libraries for each platform. 3. **Type 3 Driver**: Converts JDBC calls into a middleware-specific protocol, which is then translated into native database calls. Provides a high degree of platform independence. 4. **Type 4 Driver**: Converts JDBC calls into native database calls without using any middleware or native libraries. Pure Java driver. **Benefits of Using JDBC** 1. **Platform independence**: JDBC allows developers to write platform-independent code that can connect to different databases. 2. **Database independence**: JDBC provides a common interface for various databases, allowing developers to write database-agnostic code. 3. **Dynamic SQL execution**: JDBC allows developers to execute dynamic SQL statements that can be constructed at runtime. 4. **Support for transactions**: JDBC provides support for transactions, which allow multiple database operations to be executed as a single unit of work. **Example JDBC Code** Here's an example of using JDBC to connect to an SQLite database and execute a SQL query: ```java import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement; public class JdbcExample { public static void main(String[] args) { // Load the JDBC driver try { Class.forName("org.sqlite.JDBC"); } catch (ClassNotFoundException e) { System.out.println("Error loading JDBC driver: " + e.getMessage()); } // Connect to the database try (Connection conn = DriverManager.getConnection("jdbc:sqlite:example.db")) { // Create a statement try (Statement stmt = conn.createStatement()) { // Execute a SQL query try (ResultSet rs = stmt.executeQuery("SELECT * FROM customers")) { // Retrieve data from the result set while (rs.next()) { System.out.println("Name: " + rs.getString("name") + ", Age: " + rs.getInt("age")); } } } } catch (SQLException e) { System.out.println("Error executing SQL query: " + e.getMessage()); } } } ``` **Conclusion** In this topic, we introduced the basics of JDBC and its architecture. We also discussed the key components of JDBC and the benefits of using it for database connectivity. We provided an example of using JDBC to connect to an SQLite database and execute a SQL query. In the next topic, we will cover connecting to relational databases (MySQL, PostgreSQL) using JDBC. **What's Next** In the next topic, we will cover connecting to relational databases (MySQL, PostgreSQL) using JDBC. You will learn how to: * Connect to MySQL and PostgreSQL databases using JDBC * Execute SQL queries and retrieve data from the databases * Use prepared statements and parameterized queries to prevent SQL injection attacks * Handle exceptions and errors that occur during database operations **External Resources** For more information on JDBC, you can refer to the following resources: * [Oracle JDBC Documentation](https://docs.oracle.com/en/database/oracle/oracle-database/21/jjdbc/index.html) * [JDBC Tutorial by Tutorials Point](https://www.tutorialspoint.com/jdbc/index.htm) **Leave a Comment or Ask for Help** If you have any questions or need help with JDBC, feel free to leave a comment below.

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

public class JdbcExample {
    public static void main(String[] args) {
        // Load the JDBC driver
        try {
            Class.forName("org.sqlite.JDBC");
        } catch (ClassNotFoundException e) {
            System.out.println("Error loading JDBC driver: " + e.getMessage());
        }

        // Connect to the database
        try (Connection conn = DriverManager.getConnection("jdbc:sqlite:example.db")) {
            // Create a statement
            try (Statement stmt = conn.createStatement()) {
                // Execute a SQL query
                try (ResultSet rs = stmt.executeQuery("SELECT * FROM customers")) {
                    // Retrieve data from the result set
                    while (rs.next()) {
                        System.out.println("Name: " + rs.getString("name") + ", Age: " + rs.getInt("age"));
                    }
                }
            }
        } catch (SQLException e) {
            System.out.println("Error executing SQL query: " + e.getMessage());
        }
    }
}