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JDBC - Select Records
  • 时间:2024-11-05

JDBC - Select Records Example


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This chapter provides an example on how to select/ fetch records from a table using JDBC apppcation. Before executing the following example, make sure you have the following in place −

    To execute the following example you can replace the username and password with your actual user name and password.

    Your MySQL or whatever database you are using is up and running.

Required Steps

The following steps are required to create a new Database using JDBC apppcation −

    Import the packages − Requires that you include the packages containing the JDBC classes needed for database programming. Most often, using import java.sql.* will suffice.

    Open a connection − Requires using the DriverManager.getConnection() method to create a Connection object, which represents a physical connection with a database server.

    Execute a query − Requires using an object of type Statement for building and submitting an SQL statement to select (i.e. fetch ) records from a table.

    Extract Data − Once SQL query is executed, you can fetch records from the table.

    Clean up the environment − try with resources automatically closes the resources.

Sample Code

Copy and paste the following example in JDBCExample.java, compile and run as follows −


import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

pubpc class JDBCExample {
   static final String DB_URL = "jdbc:mysql://localhost/TUTORIALSPOINT";
   static final String USER = "guest";
   static final String PASS = "guest123";
   static final String QUERY = "SELECT id, first, last, age FROM Registration";

   pubpc static void main(String[] args) {
      // Open a connection
      try(Connection conn = DriverManager.getConnection(DB_URL, USER, PASS);
         Statement stmt = conn.createStatement();
         ResultSet rs = stmt.executeQuery(QUERY);
      ) {		      
         while(rs.next()){
            //Display values
            System.out.print("ID: " + rs.getInt("id"));
            System.out.print(", Age: " + rs.getInt("age"));
            System.out.print(", First: " + rs.getString("first"));
            System.out.println(", Last: " + rs.getString("last"));
         }
      } catch (SQLException e) {
         e.printStackTrace();
      } 
   }
}

Now let us compile the above example as follows −


C:>javac JDBCExample.java
C:>

When you run JDBCExample, it produces the following result −


C:>java JDBCExample
ID: 100, Age: 18, First: Zara, Last: Ap
ID: 101, Age: 25, First: Mahnaz, Last: Fatma
ID: 102, Age: 30, First: Zaid, Last: Khan
ID: 103, Age: 28, First: Sumit, Last: Mittal
C:>
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