HELP ! .DBF File Problems 
Author Message
 HELP ! .DBF File Problems

Hi, every one in here

I have a question about the *.dbf file for clipper.  Hope you guys can help
me.

Every one in here know that Clipper .dbf file can be view by DBU.EXE at Dos
prompt when not using, so this will cause other people use DBU.exe to view
data and changed data easily.  So is it have a way to protect the .DBF file
when not using or avoid people to change the date ?

Thanks



Fri, 08 Sep 2000 03:00:00 GMT  
 HELP ! .DBF File Problems

Quote:

>Every one in here know that Clipper .dbf file can be view by DBU.EXE at Dos
>prompt when not using, so this will cause other people use DBU.exe to view
>data and changed data easily.  So is it have a way to protect the .DBF file

You could protect the DBF by changing its first byte. The
first byte should be 83 Hex (the file has a memo field) or
03 Hex (no memo). You could easily change/restore this byte
with a Clipper low level file functions like fwrite()...

Or just give DBU.EXE the ax  :)

Quote:
>Thanks

I hope this helps,

Armando



Fri, 08 Sep 2000 03:00:00 GMT  
 HELP ! .DBF File Problems

Chong,

There is no good way to protect the DBF file from outside use by other .DBF
capable programs. That is both the good news AND the bad news. It's good
news, because it means that your Clipper program can coexist with your
clients FoxPro programs, or dBase programs. It's bad news, because it
allows your client to completely shoot themselves in the foot.

I take a stand with my clients that if I can find any evidence of tampering
of the .DBF file by outside means such as DBU or FoxPro or dBase, etc. and
they claim it's my program at fault, I will charge a hefty price for my
tech support on that call.

George



Quote:
> Hi, every one in here

> I have a question about the *.dbf file for clipper.  Hope you guys can
help
> me.

> Every one in here know that Clipper .dbf file can be view by DBU.EXE at
Dos
> prompt when not using, so this will cause other people use DBU.exe to
view
> data and changed data easily.  So is it have a way to protect the .DBF
file
> when not using or avoid people to change the date ?

> Thanks



Fri, 08 Sep 2000 03:00:00 GMT  
 HELP ! .DBF File Problems

You have the source code to DBU.EXE.  Why don't you  rewrite it to not allow
adds.  For example on the browse screen you can tell it to stop on EOF
marker.  Or something simple like open all database as READONLY.

Quote:

>Hi, every one in here

>I have a question about the *.dbf file for clipper.  Hope you guys can help
>me.

>Every one in here know that Clipper .dbf file can be view by DBU.EXE at Dos
>prompt when not using, so this will cause other people use DBU.exe to view
>data and changed data easily.  So is it have a way to protect the .DBF file
>when not using or avoid people to change the date ?

>Thanks



Sat, 09 Sep 2000 03:00:00 GMT  
 HELP ! .DBF File Problems

You have a few options:

1) Limit the availability of DBU or alter it to not allow editing or
appending.
2) Encrypt your file.
3) Fire anybody that directly accesses your tables.
4) Combinations of the above.
5) Abandon DBFs in favor of a database engine, possibly using an n-tier
approach.
--
Richard Mitchell
http://www.geocities.com/~bytemaster
bytemaster at ibm.net



Quote:
> Hi, every one in here

> I have a question about the *.dbf file for clipper.  Hope you guys can
help
> me.

> Every one in here know that Clipper .dbf file can be view by DBU.EXE at
Dos
> prompt when not using, so this will cause other people use DBU.exe to
view
> data and changed data easily.  So is it have a way to protect the .DBF
file
> when not using or avoid people to change the date ?

> Thanks



Sun, 10 Sep 2000 03:00:00 GMT  
 HELP ! .DBF File Problems

Hi,
has any one any experience with 'ADVANTAGE DATABASE SERVER ON NT' and
TCP/IP libraries using Causeway. My application works fine with the NLM
version, but falls over with the NT-Version using TCP/IP, BUT using the
SPX libraries and Causeway its fine, a bit slow but fine.

Regards
--
Arnold Johnson



Mon, 11 Sep 2000 03:00:00 GMT  
 
 [ 8 post ] 

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