autogenerated keys do not work with single column table

[Bob Jaster <bo...@yahoo.com>]

I have discovered that if I create a table with only one column, such as
   
  CREATE TABLE mo.company (
 id      BIGINT    NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
 PRIMARY KEY (id)
);
   
  then execute 
   
    String sql = "INSERT INTO mo.company VALUES (DEFAULT)";
  PreparedStatement preparedStatement = connection.prepareStatement(sql, Statement.RETURN_GENERATED_KEYS);
    preparedStatement.executeUpdate();
    ResultSet resultSet = preparedStatement.getGeneratedKeys();
    System.out.println("resultSet.next()==" + resultSet.next());
  Object object = resultSet.getObject(1);
  if (object == null) {
   System.out.println("object is null");
  } else {
   long id = resultSet.getLong(1);
   System.out.println("id==" + id);
  }

  I always get null returned from resultSet.getObject(1), whereas if I add a second column to the table (a VARCHAR(100)) then I get the generated key value.
  
Is this a bug?
   
  Bob Jaster
   
   

 		
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Re: autogenerated keys do not work with single column table

[Deepa Remesh <dr...@gmail.com>]

On 9/25/06, Bob Jaster <bo...@yahoo.com> wrote:
> I have discovered that if I create a table with only one column, such as
>
> CREATE TABLE mo.company (
>  id      BIGINT    NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH 1,
> INCREMENT BY 1),
>  PRIMARY KEY (id)
> );
>
> then execute
>
>   String sql = "INSERT INTO mo.company VALUES (DEFAULT)";
>   PreparedStatement preparedStatement = connection.prepareStatement(sql,
> Statement.RETURN_GENERATED_KEYS);
>     preparedStatement.executeUpdate();
>     ResultSet resultSet =
> preparedStatement.getGeneratedKeys();
>     System.out.println("resultSet.next()==" + resultSet.next());
>   Object object = resultSet.getObject(1);
>   if (object == null) {
>    System.out.println("object is null");
>   } else {
>    long id = resultSet.getLong(1);
>    System.out.println("id==" + id);
>   }
>
> I always get null returned from resultSet.getObject(1), whereas if I add a
> second column to the table (a VARCHAR(100)) then I get the generated key
> value.
>
> Is this a bug?

I tried your repro and I get the same problem with latest official
release (10.1.3.1). However, when I tried with the latest 10.1
codeline and with 10.2 release candidate, I get correct results. So I
think there was a bug which has been fixed in the latest codelines.

It would be nice if you can try your application with the 10.2 release
candidate and confirm this is not a problem. Details of 10.2 release
candidate is available at
http://wiki.apache.org/db-derby/TenTwoRelease

Thanks,
Deepa