Check if DB is empty

Hi,

Is there any function to check if a DBF file has no records?

Thanks

Nevermind, I did it like this:

use ....
if bof()==eof()
...
return
endif

It's working (at least for now)


"Pablo García" <pgarcia@chasque.net> escribió en el mensaje
news:1148u2oaqlpv536@news.supernews.com...
> Hi,
>
> Is there any function to check if a DBF file has no records?
>
> Thanks
>

Pablo,

If you are using DbServer classes, DbServer:RecCount

If you are using workareas and functional form of database manipulation
Alias->( RecCount() ).

HTH,
--
Johan Nel
Pretoria, South Africa.

"Pablo García" <pgarcia@chasque.net> wrote in message
news:1148u2oaqlpv536@news.supernews.com...
> Hi,
>
> Is there any function to check if a DBF file has no records?
>
> Thanks
>
>

"Pablo García" <pgarcia@chasque.net> wrote in message
news:1148uuqftks0422@news.supernews.com...
[...] 
[...]
> Nevermind, I did it like this:
>
> use ....
> if bof()==eof()
>         ....
>         return
> endif
>
> It's working (at least for now)

It's only working because you have most likely only tested against an empty
database.  If you're anywhere other than bof or eof in a database with one
or more records, both will return False, yet still be equal and your code
will incorrectly indicate an empty database.  A database is empty if the
record count is zero - don't try to be clever about it, just use lastrec().

--
Ray Marron

Thanks, you were right.

Finally I used:

If reccount()==0
..
return
endif


"Ray Marron" <me@privacy.net> escribió en el mensaje
news:3ajfciF6c1geqU1@individual.net...
> "Pablo García" <pgarcia@chasque.net> wrote in message
> news:1148uuqftks0422@news.supernews.com...
> [...] 
> [...] 
>
> It's only working because you have most likely only tested against an
> empty
> database.  If you're anywhere other than bof or eof in a database with one
> or more records, both will return False, yet still be equal and your code
> will incorrectly indicate an empty database.  A database is empty if the
> record count is zero - don't try to be clever about it, just use
> lastrec().
>
> --
> Ray Marron
>
>

What about lastrec()?  According to something I read, lastrec() supercedes
reccount()...

--
Rob Grattan
R&D Software Pty. Ltd.

On Fri, 25 Mar 2005 21:07:54 -0300, "Pablo García"
<pgarcia@chasque.net> wrote:

>Thanks, you were right.
>
>Finally I used:
>
>If reccount()==0
>        ...
>        return
>endif
>

... and what happened if the dbf does have some records but all
deleted?

--
Bambang P
http://bpranoto.tripod.com

In article <4h3a41ds5gspau9gmdmaihbdd3d0phq6kq@4ax.com>
bpranoto_nospam@hotpop.com "Bambang P" writes:

> On Fri, 25 Mar 2005 21:07:54 -0300, "Pablo García"
> <pgarcia@chasque.net> wrote:
> 
>
> ... and what happened if the dbf does have some records but all
> deleted?

Hi Bambang,
It rather depends on whether one wants to account for them, such
records can after all be undeleted.  I can't think of a quick way
of checking for the condition you say, but something like this
should work (apologies for the S87 syntax):

FUNCTION is_emptyDBF
PARAMETER dbfname
PRIVATE savearea, numrecs, numdel

savearea = SELECT()
SELECT 0
USE (dbfname) EXCLUSIVE 
numrecs = LASTREC()
numdel = 0
IF numrecs > 0
*-- this is likely to be S-L-O-W --*
COUNT TO numdel FOR deleted()
ENDIF
CLOSE
SELECT (savearea)
RETURN (numrecs - numdel == 0)

Even that is incomplete as it doesn't take into account any
conditional index; I think the OP will have to write the function
themself, perhaps using the workarea/alias as a parameter...

Pete
--
"We have not inherited the earth from our ancestors,
we have borrowed it from our descendants."

Slowly knock the file with your finger tips.
If it sounds hollow, then it's empty.

Andi
PS: Sorry.. I just quoted someone's answer years ago ;-)

<<
"Pablo García" <pgarcia@chasque.net> wrote:

Hi,
Is there any function to check if a DBF file has no records?
Thanks 

On Sat, 26 Mar 2005 08:58:42 +0000 (UTC), pete@nospam.demon.co.uk
wrote:
 
>
>Hi Bambang,
>It rather depends on whether one wants to account for them, such
>records can after all be undeleted.  I can't think of a quick way
>of checking for the condition you say, but something like this
>should work (apologies for the S87 syntax):
>

Hi Pete,

If the OP doesn't want take into account deleted records he can
simply:

use HISDATA
if Eof()
........

to check if his data contains deleted record:

use HISDATA
if Eof() and Reccount() <> 0
? "There are some records but all are deleted"
--
Bambang P
http://bpranoto.tripod.com