Connections
Description
A Connection represents a database session.
Explanation
DriverManager can create one from a database URL and credentials.
Example
java.sql.Connection con = java.sql.DriverManager.getConnection(url, user, password);← Chapter 10 — Threads, Networking & JDBC
36. JDBC Database Connectivity
mixed
Description
JDBC is Java's standard API for working with relational databases. A JDBC driver connects Java to a specific database system such as MySQL or PostgreSQL.
Use PreparedStatement for values supplied by users or variables. It separates SQL code from data and helps prevent SQL injection.
Subtopics
Prepared statements
Description
PreparedStatement safely binds values.
Explanation
Question marks mark values that are set separately.
Example
statement.setString(1, "Aditi");Explanation
Use try-with-resources for Connection, PreparedStatement, and ResultSet so they close even when an error occurs. Store credentials outside source code, for example in environment-based configuration.
Example
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
public class JdbcDemo {
public static void main(String[] args) throws Exception {
String url = "jdbc:mysql://localhost:3306/school";
try (Connection con = DriverManager.getConnection(url, "user", "password");
PreparedStatement statement = con.prepareStatement("SELECT * FROM students WHERE name = ?")) {
statement.setString(1, "Aditi");
System.out.println("Query prepared");
}
}
}Key points
- JDBC connects Java to databases.
- PreparedStatement binds values safely.
- Close database resources automatically.