How to do Database Connection Using JDBC thin Driver

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This is one of the most commonly asked questions from JDBC fundamentals, and knowing all the steps of JDBC connection is important.

import java.sql.*;

class JDBCTest {

public static void main (String args []) throws Exception

{

//Load driver class

Class.forName (“oracle.jdbc.driver.OracleDriver”);

//Create connection

Connection conn = DriverManager.getConnection

(“jdbc:oracle:thin:@hostname:1526:testdb”, “scott”, “tiger”);

// @machineName:port:SID,   userid,  password

 

Statement stmt = conn.createStatement();

ResultSet rs = stmt.executeQuery(“select ‘Hi’ from dual”);

while (rs.next())

System.out.println (rs.getString(1));   // Print col 1 => Hi

stmt.close();

}

}

To establish a database connection using JDBC thin driver in Core Java, you typically follow these steps:

  1. Load the JDBC driver: Use Class.forName() to dynamically load the JDBC driver for your database. For a thin driver, this is usually provided by the database vendor.
    java
    Class.forName("oracle.jdbc.driver.OracleDriver"); // Example for Oracle database
  2. Create a Connection: Use the DriverManager.getConnection() method to establish a connection to the database. You need to provide the URL of your database, username, and password.
    java
    String url = "jdbc:oracle:thin:@localhost:1521:orcl"; // Example for Oracle database
    String username = "yourUsername";
    String password = "yourPassword";    Connection connection = DriverManager.getConnection(url, username, password);

    Replace the URL, username, and password with your specific database details.

  3. Execute SQL Queries: Once the connection is established, you can create a Statement or PreparedStatement to execute SQL queries.
    java
    Statement statement = connection.createStatement();
    ResultSet resultSet = statement.executeQuery("SELECT * FROM your_table");

    Replace your_table with the actual table name.

  4. Process the Results: Process the results of your SQL queries, if any, using the ResultSet.
    java
    while (resultSet.next()) {
    // Process each row of the result set
    // Example: String value = resultSet.getString("column_name");
    }
  5. Close Resources: Always close the ResultSet, Statement, and Connection objects to release resources.
    java
    resultSet.close();
    statement.close();
    connection.close();

Here’s a complete example:

java

import java.sql.*;

public class JDBCExample {
public static void main(String[] args) {
try {
// Load the JDBC driver
Class.forName(“oracle.jdbc.driver.OracleDriver”);

// Create a connection
String url = “jdbc:oracle:thin:@localhost:1521:orcl”;
String username = “yourUsername”;
String password = “yourPassword”;
Connection connection = DriverManager.getConnection(url, username, password);

// Execute a SQL query
Statement statement = connection.createStatement();
ResultSet resultSet = statement.executeQuery(“SELECT * FROM your_table”);

// Process the results
while (resultSet.next()) {
// Process each row of the result set
// Example: String value = resultSet.getString(“column_name”);
}

// Close resources
resultSet.close();
statement.close();
connection.close();
} catch (Exception e) {
e.printStackTrace();
}
}
}

Replace the placeholders (yourUsername, yourPassword, jdbc:oracle:thin:@localhost:1521:orcl, your_table, etc.) with your actual database details and SQL queries.