JDBC Tutorials - Herong's Tutorial Examples - v3.12, by Dr. Herong Yang
"INSERT INTO" Statements with INDENTITY Columns
This section describes what will happen if you try to insert rows with values for GENERATED ALWAYS AS IDENTITY columns.
An INDENTITY column is a special column in a table that is defined to have its values automatically added with a sequence number generator. An INDENTITY column is normally used for the primary key column in a table. For example, the ID column in the Profile table created in a previous tutorial is an INDENTITY column.
If an IDENTITY column is defined with "GENERATED ALWAYS AS IDENTITY" and you try to add values to this column in INSERT statements, you will get an error as shown in the sample program below:
/* DerbyInsertIdentity.java * Copyright (c) HerongYang.com. All Rights Reserved. */ import java.sql.*; public class DerbyInsertIdentity { public static void main(String [] args) { Connection con = null; try { con = DriverManager.getConnection("jdbc:derby://localhost/TestDB"); Statement sta = con.createStatement(); // insert a single row int count = sta.executeUpdate( "INSERT INTO Profile" + " (ID, FirstName, LastName, ModTime)" + " VALUES (1001, 'Herong', 'Yang', '2017-04-01')"); System.out.println("Number of rows inserted: "+count); sta.close(); con.close(); } catch (Exception e) { System.err.println("Exception: "+e.getMessage()); } } }
Here is the error message from this program:
Exception: Attempt to modify an identity column 'ID'.
Table of Contents
JDBC (Java Database Connectivity) Introduction
Installing and Running Java DB - Derby
Derby (Java DB) JDBC DataSource Objects
►Java DB (Derby) - DML Statements
Tables with Primary Key Column "GENERATED ... AS IDENTITY"
►"INSERT INTO" Statements with INDENTITY Columns
Handling Date and Timestamp Values
Java DB (Derby) - ResultSet Objects of Queries
Java DB (Derby) - PreparedStatement
MySQL JDBC Driver (MySQL Connector/J)
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 - Reference Implementation of JdbcRowSet
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