Creating Tables with AUTO_INCREMENT Columns

This section describes how to create a table with an AUTO_INCREMENT column.

Different database servers have different ways to support columns with automatically incremented values. MySQL uses the key word AUTO_INCREMENT to specify an auto-incrementing column.

In order to try AUTO_INCREMENT columns and provide a test table for testing DML (Data Manipulation Statements), I wrote the following program to create a table called "Profile" with the primary key column defined as an AUTO_INCREMENT column:

/**
 * MySqlAutoIncrement.java
 * Copyright (c) 2015, HerongYang.com, All Rights Reserved.
 */
import java.sql.*;
import javax.sql.*;
public class MySqlAutoIncrement {
  public static void main(String [] args) {
    Connection con = null;
    try {
    	
// Setting up the DataSource object
      com.mysql.jdbc.jdbc2.optional.MysqlDataSource ds 
        = new com.mysql.jdbc.jdbc2.optional.MysqlDataSource();
      ds.setServerName("localhost");
      ds.setPortNumber(3306);
      ds.setDatabaseName("test");
      ds.setUser("root");
      ds.setPassword("TopSecret");

// Getting a connection object
      con = ds.getConnection();

// Creating a database table
      Statement sta = con.createStatement(); 
      int count = sta.executeUpdate(
        "CREATE TABLE Profile ("
        + " ID INTEGER PRIMARY KEY AUTO_INCREMENT,"
        + " FirstName VARCHAR(20) NOT NULL,"
        + " LastName VARCHAR(20),"
        + " Point REAL DEFAULT 0.0,"
        + " BirthDate DATE DEFAULT '1988-12-31',"
        + " ModTime TIMESTAMP DEFAULT '2006-12-31 23:59:59.999')");
      System.out.println("Table created.");
      sta.close();        

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

When you run this program, table Profile will be created. But you run it again, you will get an exception:

C:\herong>javac -cp .;\local\lib\mysql-connector-java-5.1.38-bin.jar
  DerbyIdentityColumn.java

C:\herong>java -cp .;\local\lib\mysql-connector-java-5.1.38-bin.jar
  DerbyIdentityColumn

Table created.


C:\herong>java -cp .;\local\lib\mysql-connector-java-5.1.38-bin.jar
  DerbyIdentityColumn

Exception: Table 'profile' already exists

Last update: 2015.

Table of Contents

 About This Book

 Introduction of SQL

 MySQL Introduction and Installation

 Introduction of MySQL Programs

 Perl Programs and MySQL Servers

 PHP Programs and MySQL Servers

Java Programs and MySQL Servers

 MySQL Connector/J - Download and Installation

 Loading JDBC Driver Class - com.mysql.jdbc.Driver

 JDBC Driver Connection URL

 Creating Connections with DataSource Class

 Getting Driver and Server Information

Creating Tables with AUTO_INCREMENT Columns

 "INSERT INTO" Statements

 Datatypes and Data Literals

 Operations and Expressions

 Character Strings and Bit Strings

 Commonly Used Functions

 Table Column Types for Different Types of Values

 Using DDL to Create Tables and Indexes

 Using DML to Insert, Update and Delete Records

 Using SELECT to Query Database

 Transaction Management and Isolation Levels

 Locks Used in MySQL

 Defining and Calling Stored Procedures

 Variables, Loops and Cursors Used in Stored Procedures

 Outdated Tutorials

 References

 PDF Printing Version