Java - JDBC Connectivity in Java

1. What is JDBC?

JDBC (Java Database Connectivity) is an API in Java that allows a Java program to connect to a database and interact with it. Using JDBC, you can send SQL queries to a database and receive results.

It enables programs to:

Insert data
Retrieve data
Update records
Delete records

JDBC works with many database systems such as MySQL, Oracle, PostgreSQL, and others through specific drivers.

2. Why is JDBC Important?

Allows applications to store persistent data
Connects Java applications with databases
Essential for enterprise and web applications
Enables real-world data processing

Without database connectivity, programs cannot efficiently manage large structured data.

3. JDBC Architecture Components

JDBC includes several key parts:

Driver Manager
Manages database drivers and establishes connections.

Driver
Software that enables communication between Java and a specific database.

Connection
Represents a session between the Java application and database.

Statement
Used to send SQL queries to the database.

ResultSet
Stores data returned from queries.

4. Steps to Connect to a Database

Import JDBC packages
Load the driver
Establish connection
Create statement
Execute SQL query
Process results
Close connection

5. Simple Example

import java.sql.*;

public class Demo {
    public static void main(String[] args) {
        try {
            Connection con = DriverManager.getConnection(
                "jdbc:mysql://localhost:3306/testdb",
                "username",
                "password"
            );

            Statement stmt = con.createStatement();
            ResultSet rs = stmt.executeQuery("SELECT * FROM students");

            while(rs.next()){
                System.out.println(rs.getString(1));
            }

            con.close();
        } catch(Exception e){
            System.out.println(e);
        }
    }
}

This program connects to a database, retrieves records, and prints them.

6. Types of JDBC Statements

Statement
Used for simple SQL queries.

PreparedStatement
Used for dynamic queries and prevents SQL injection.

CallableStatement
Used to execute stored procedures.

7. Advantages of JDBC

Standard API for database interaction
Supports multiple databases
Enables dynamic data handling
Widely used in enterprise applications

Summary

JDBC connectivity allows Java applications to communicate with databases by sending SQL commands and receiving results. It plays a crucial role in building applications that manage and process persistent data.