OpenEuphoria

Re: EDS Autonumber

• Posted by Ryan W. Johnson <ryanj at fluidae.com> Dec 03, 2005
• 527 views

cklester wrote:
> 
> Greg Haberek wrote:
> > 
> > > Has anyone got a way of generating an autonumber under the native eds sys=
> > tem?
> > 
> > I use something similar to this. Keys start at one. When generating a
> > new key, it grabs the last (and highest) then returns the next number.
> > If the table is empty, it returns 1, the first key.
> > 
> > }}}
<eucode>
> > global function db_next_key()
> > 
> >     integer count
> > 
> >     count = db_table_size()
> >     if count = 0 then
> >         key = 0
> >     else
> >         key = db_record_key( count )
> >     end if
> > 
> >     return key+1
> > end function
> > </eucode>
{{{

> 
> You'd need something like
> 
>    while keyExists( count ) do
>         count += 1
>    end while
> 
> so as to avoid duplicate keys in cases where records get deleted.
> 
> -=ck
> "Programming in a state of Euphoria."
> <a
> href="http://www.cklester.com/euphoria/">http://www.cklester.com/euphoria/</a>



I made a good-sized database application in Visual Basic 6.0, using an ODBC
connection to an mdb (Access) file. I always made keys using the maximum key
value + 1. That way, it will still work after you delete records.

The only problem i could see is once you hit the highest value possible, you
wolud have to wrap around back to 0, and check to make sure you only use
unused values.

~Ryan W. Johnson

[cool signature here, if i ever think of one...]