What is JDBC?

JDBC (Java Database Connectivity) is an API for connecting and interacting with databases from Java applications. It provides a standard way to access various types of DBMS, abstracting from their specifics.

Key components of JDBC:

• DriverManager: A class that manages database drivers. It finds the appropriate driver for a given database URL.
• Connection: An object representing an established connection to a database. Used to create Statement objects.
• Statement: An object used to execute static SQL queries.
• PreparedStatement: An extension of Statement designed for executing parameterized SQL queries. It improves performance and security by preventing SQL injection.
• CallableStatement: An extension of PreparedStatement for calling stored procedures.
• ResultSet: An object representing a set of data obtained as a result of executing an SQL query. It allows iteration over the result rows.

Example of using JDBC:

// 1. Registering the driver (often automatic with modern JDBC drivers)
// Class.forName("com.mysql.cj.jdbc.Driver");

// 2. Establishing a connection
String url = "jdbc:mysql://localhost:3306/mydatabase";
String user = "username";
String password = "password";

try (Connection connection = DriverManager.getConnection(url, user, password)) {
    // 3. Creating Statement or PreparedStatement
    String sql = "SELECT * FROM users WHERE id = ?";
    try (PreparedStatement preparedStatement = connection.prepareStatement(sql)) {
        // 4. Setting parameters (for PreparedStatement)
        preparedStatement.setInt(1, 123);

        // 5. Executing the query and obtaining ResultSet
        try (ResultSet resultSet = preparedStatement.executeQuery()) {
            // 6. Processing results
            while (resultSet.next()) {
                int id = resultSet.getInt("id");
                String name = resultSet.getString("name");
                System.out.println("ID: " + id + ", Name: " + name);
            }
        }
    }
} catch (SQLException e) {
    e.printStackTrace();
}

JDBC is a low-level API that allows detailed control over database interaction. Above JDBC are abstractions such as JPA (Java Persistence API) and ORM frameworks like Hibernate, which simplify working with databases by providing an object-oriented approach.