Incrementing primary key

[Pradeep Adibatla]

i have a primary key pid in a class called project...

I have a struts action class called createproject action where i set the pid for the project...

so I wrote a query

   String query = "select max(ProjectId)from projecttable";    

and i want to go through result set and increment it likewise as:

 

rs=stmt.executeQuery(query);
                    
                    
                    if(rs.next())
                    {
                       System.out.println("in if");
                       while(rs.next())
                       {
                           System.out.println("in while ");
                           project.setPId(project.getPId()+1);
                       }
                    }
                    else
                    {
                        System.out.println("In else !");
                        project.setPId(1);
                    }

   

it's not going into while loop...

When i run the query it works fine

what should be the change??

[Lorand Komaromi]

Pradeep Adibatla wrote: while(rs.next())

This doesn't make any sense as your SQL query will yield a single result row...

[Edwin Dalorzo]

As Lorand said, there is only one record returned every time you run your query. When the if statement is executed, you visit the first row, then the while statement is executed, but since there are no more rows to visit, it will always yield false.

[Scott Selikoff]

Are you aware rs.next() isn't a read-only call? Anytime you use it, you move the pointer in the result set. In order to hit the while loop in your code, you'd have to have at least 2 records from the result.