ResultSet Cursor Initial Position: Before First Row

JDBC Tutorials - Herong's Tutorial Examples

∟Java DB (Derby) - ResultSet Objects of Queries

∟ResultSet Cursor Initial Position: Before First Row

This section describes the ResultSet cursor initial position: before first row. next() should be called to move the cursor to the first row.

Right after the ResultSet object is returned from the executeQuery() call, the ResultSet cursor is positioned before the first row. You need to call next() once to move the cursor to the first row. If you missed this call, you will get an error message as shown by this sample program:

/* DerbyResultSetNoNext.java
 * Copyright (c) HerongYang.com. All Rights Reserved.
 */
import java.sql.*;
public class DerbyResultSetNoNext {
  public static void main(String [] args) {
    Connection con = null;
    try {
      con = DriverManager.getConnection("jdbc:derby://localhost/TestDB");
      Statement sta = con.createStatement();

// Catch the ResultSet object
      ResultSet res = sta.executeQuery("SELECT * FROM Profile");

// Skip calling next()
//    res.next();

// Try to get column values
      String firstName = res.getString("FirstName");
      String lastName = res.getString("LastName");

// Close ResultSet
      res.close();

      sta.close();
      con.close();
    } catch (Exception e) {
      System.err.println("Exception: "+e.getMessage());
    }
  }
}

Run this program to see the error if res.next() is not called after executeQuery():

Exception: Invalid operation at current cursor position.

Table of Contents

About This Book

JDBC (Java Database Connectivity) Introduction

JDK (Java SE) Installation

Installing and Running Java DB - Derby

Derby (Java DB) JDBC Driver

Derby (Java DB) JDBC DataSource Objects

Java DB (Derby) - DML Statements

►Java DB (Derby) - ResultSet Objects of Queries

What Is ResultSet?

ResultSet Cursor and Scrollability

►ResultSet Cursor Initial Position: Before First Row

Retrieving Column Values with getXXX() Methods

ResultSet Default Type: Forward-only

Scrollable ResultSet and Moving Cursor Backward

ResultSet Objects with Update Capability

insertRow() - Inserting New Rows through ResultSet Objects

updateXXX() - Updating Column Values for Row Update or Insert

deleteRow() - Deleting Rows through ResultSet Objects

Java DB (Derby) - PreparedStatement

MySQL Installation on Windows

MySQL JDBC Driver (MySQL Connector/J)

MySQL - PreparedStatement

MySQL - Reference Implementation of JdbcRowSet

MySQL - JBDC CallableStatement

MySQL CLOB (Character Large Object) - TEXT

MySQL BLOB (Binary Large Object) - BLOB

Oracle Express Edition Installation on Windows

Oracle JDBC Drivers

Oracle - Reference Implementation of JdbcRowSet

Oracle - PreparedStatement

Oracle - JBDC CallableStatement

Oracle CLOB (Character Large Object) - TEXT

Oracle BLOB (Binary Large Object) - BLOB

Microsoft SQL Server Express Edition

Microsoft JDBC Driver for SQL Server

Microsoft JDBC Driver - Query Statements and Result Sets

Microsoft JDBC Driver - DatabaseMetaData Object

Microsoft JDBC Driver - DDL Statements

Microsoft JDBC Driver - DML Statements

SQL Server - PreparedStatement

SQL Server CLOB (Character Large Object) - TEXT

SQL Server BLOB (Binary Large Object) - BLOB

JDBC-ODBC Bridge Driver - sun.jdbc.odbc.JdbcOdbcDriver

JDBC-ODBC Bridge Driver - Flat Text Files

JDBC-ODBC Bridge Driver - MS Access

JDBC-ODBC Bridge Driver - MS SQL Server

Summary of JDBC Drivers and Database Servers

Using Connection Pool with JDBC

Archived Tutorials

Full Version in PDF/EPUB