JDBC Tutorials - Herong's Tutorial Examples - v3.14, by Herong Yang
"UPDATE" Statements
This section describes how to update existing data rows with UPDATE statements.
UPDATE statements are also commonly used by database applications when users making changes to field values on the UI. An UPDATE statement should have a SET clause to provide a list of columns with new values and a WHERE clause to identify the rows to be updated.
UPDATE statements should be executed with the executeUpdate() method. The Java tutorial program below shows you how to update rows.
/* DerbyUpdateRows.java * Copyright (c) HerongYang.com. All Rights Reserved. */ import java.sql.*; public class DerbyUpdateRows { public static void main(String [] args) { Connection con = null; try { con = DriverManager.getConnection("jdbc:derby://localhost/TestDB"); Statement sta = con.createStatement(); // updating multiple rows int count = sta.executeUpdate( "UPDATE Profile SET ModTime = '2017-04-01 23:59:59.999'" + " WHERE ID > 6"); System.out.println("Number of rows updated: "+count); // Checking updated rows ResultSet res = sta.executeQuery( "SELECT * FROM Profile"); System.out.println("List of Profiles: "); while (res.next()) { System.out.println( " "+res.getInt("ID") + ", "+res.getString("FirstName") + ", "+res.getString("LastName") + ", "+res.getFloat("Point") + ", "+res.getDate("BirthDate") + ", "+res.getTimestamp("ModTime")); } res.close(); sta.close(); con.close(); } catch (Exception e) { System.err.println("Exception: "+e.getMessage()); } } }
The output confirms that 7 rows were updated with a new timestamp in the ModTime column:
Number of rows updated: 7 List of Profiles: 1, Herong, null, 0.0, 1999-12-31, 2016-12-31 23:59:59.999 2, Janet, Gates, 999.99, 2004-10-13, 2016-12-31 23:59:59.999 3, 1403, 896f7, 62.594772, 1999-12-31, 2016-12-31 23:59:59.999 4, 256d, aa3f5, 203.51392, 1999-12-31, 2016-12-31 23:59:59.999 5, d7a, 3a06f, 604.9995, 1999-12-31, 2016-12-31 23:59:59.999 6, 8ef, 466ca, 31.71128, 1999-12-31, 2016-12-31 23:59:59.999 7, 1a34, 59e87, 674.8019, 1999-12-31, 2017-04-01 23:59:59.999 8, 10cc, ab361, 325.30505, 1999-12-31, 2017-04-01 23:59:59.999 9, 11bd, 99552, 315.1111, 1999-12-31, 2017-04-01 23:59:59.999 10, 8c4, 68909, 23.095905, 1999-12-31, 2017-04-01 23:59:59.999 11, 17e1, 99a5d, 186.09494, 1999-12-31, 2017-04-01 23:59:59.999 12, 1ea2, 480c7, 131.6408, 1999-12-31, 2017-04-01 23:59:59.999 13, Keith, Harris, 0.0, 2010-03-01, 2017-04-01 23:59:59.999
Table of Contents
JDBC (Java Database Connectivity) Introduction
Installing and Running Derby (Java DB)
Derby (Java DB) JDBC DataSource Objects
►Derby (Java DB) - DML Statements
Tables with Primary Key Column "GENERATED ... AS IDENTITY"
"INSERT INTO" Statements with INDENTITY Columns
Handling Date and Timestamp Values
Derby (Java DB) - ResultSet Objects of Queries
Derby (Java DB) - PreparedStatement
Summary of JDBC Drivers and Database Servers