Describe various steps of JDBC with code snippets.

9.B] Describe various steps of JDBC with code snippets.

Answer:-

5 Steps to connect to the database in java

There are 5 steps to connect any java application with the database in java using JDBC. They are as follows:

1. Register the driver class
2. Creating connection
3. Creating statement
4. Executing queries
5. Closing connection

1. Register the Driver Class

• Purpose: Load the JDBC driver to connect to the database.
• Method: Class.forName("driverClassName")

Class.forName("com.mysql.cj.jdbc.Driver"); // Example for MySQL

2. Create the Connection Object

• Purpose: Establish a connection to the database.
• Method: DriverManager.getConnection(url, user, password)

String url = "jdbc:mysql://localhost:3306/mydatabase";
String user = "username";
String password = "password";
Connection con = DriverManager.getConnection(url, user, password);

3. Create & Execute Query

• Purpose: Create a statement and execute SQL queries.
• Methods: createStatement() and executeQuery()

Statement st = con.createStatement();
String sql = "SELECT id, name FROM users";
ResultSet rs = st.executeQuery(sql);

4. Process Data Returned from DBMS

• Purpose: Iterate through the ResultSet to process the retrieved data.
• Method: rs.next()

while (rs.next()) {
    int id = rs.getInt(1); // Retrieve the first column
    String name = rs.getString(2); // Retrieve the second column
    System.out.println(id + " " + name);
}

5. Close the Connection Object

• Purpose: Close the ResultSet, Statement, and Connection to release resources.
• Methods: rs.close(), st.close(), con.close()

rs.close();
st.close();
con.close();

Summary

1. Register the Driver:

   Class.forName("com.mysql.cj.jdbc.Driver");

2. Create Connection:

   Connection con = DriverManager.getConnection(url, user, password);

3. Create and Execute Query:

   Statement st = con.createStatement();
   ResultSet rs = st.executeQuery("SELECT id, name FROM users");

4. Process Data:

   while (rs.next()) {
       int id = rs.getInt(1);
       String name = rs.getString(2);
       System.out.println(id + " " + name);
   }

5. Close Resources:

   rs.close();
   st.close();
   con.close();

This process covers the essential steps to connect to a database, execute queries, and handle the results in a Java application using JDBC.