[comp.databases] dBASE IV Problem - .DBT files

pelakh@cerc.wvu.wvnet.edu (Boris Pelakh) (07/08/89)

I am running dBASE IV Ver. 1.0 on an IBM PS/2 System 50.
Since we have several people using the system, we have
used the PROTECT facility to create a user identification
system and restrict data access/modification proveleges.

Since then we've had problems with .DBT files (the ones
containing MEMO fields). Whenever an error occurs in the
system, (in the middle of a report, for example) the system
tends to llos the pointers from ther DBF file to the DBT file,
resulting in a very confusing mess in the memo fields and 
a large lost time for recoivering data. 

Any Ideas ?! Suggestions ?! Anything ? 

Some other stuff :

	We have 1 Meg of memory and DOS sees only 640K. Any
	programs recommended to use with dBASE 4 for such
	purposes (anyone ever hear of HICARD 286 ?) ?

	We are about to install our database on a network,
	using the IBM baseband network cards and PC Lan Server
	Version 1.3 Any experience out there with this network
	and/or configuration ?


Boris Pelakh

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awd@dbase.UUCP (Alastair Dallas) (07/12/89)

I'm sorry I can't offer much help as to your DBT file problems.  Since the
DBF and DBT are separate files linked by pointers, system errors which
corrupt the pointers are naturally going to cause "a big mess."  From
your comments the exact nature of the fault was not clear, but it sounds
like you are able to recover your data.

We have used HiCards here at A-T with some success--at least, I don't 
remember any serious problems--but that was with Compaq 386s and ATs,
not PS/2s.  I think several people here use 386-to-the-Max.

/alastair/

pelakh@babcock.cerc.wvu.wvnet.edu (Boris Pelakh) (07/13/89)

From article <150@dbase.UUCP>, by awd@dbase.UUCP (Alastair Dallas):
> 
> I'm sorry I can't offer much help as to your DBT file problems.  Since the
> DBF and DBT are separate files linked by pointers, system errors which
> corrupt the pointers are naturally going to cause "a big mess."  From
> your comments the exact nature of the fault was not clear, but it sounds
> like you are able to recover your data.
>

The problem turned out to be not dBASE - we did a chkdsk and found some
trouble sectors ... Once that was corrected everything went smooth

> We have used HiCards here at A-T with some success--at least, I don't 
> remember any serious problems--but that was with Compaq 386s and ATs,
> not PS/2s.  I think several people here use 386-to-the-Max.
> 

I talked to the people at Rybs Electronics (mfg's of HiCard) and we were
told that they do not work on micro-channel machines. We cannot use 386 Max
on our System 50's and System 30/286's. We were recommended to use a piece
of software called Above Disc that (hopefully) allows use of extended memory
on Micro-Channel machines. Any experience with it ?

------------------------------------------------------------------------------
Boris Pelakh			  | "I swear by my life and my love of it
pelakh@cerc.wvu.wvnet.edu	  |  that I will never live for the sake of
un027707@wvnvaxa.wvnvms.wvnet.edu |  another man, nor ask another to live for
--------------------------------- |  mine ..."      
"Violence is the last resort of   |                 John Galt, "Atlas Shrugged"
 the incompetent"	S. Hardin |
	             "Foundation" |
------------------------------------------------------------------------------

aiko@cs.odu.edu (John K Hayes) (07/17/89)

In article <171@cerc.wvu.wvnet.edu.edu> pelakh@babcock.cerc.wvu.wvnet.edu (Boris Pelakh) writes:
>From article <150@dbase.UUCP>, by awd@dbase.UUCP (Alastair Dallas):
>> 
>> I'm sorry I can't offer much help as to your DBT file problems.  Since the
>> DBF and DBT are separate files linked by pointers, system errors which
>> corrupt the pointers are naturally going to cause "a big mess."  From
>> your comments the exact nature of the fault was not clear, but it sounds
>> like you are able to recover your data.
>>


I have had a bit of trouble with DBT files too.  I modified a database
already in use by a Clipper program by changing a few Character fields
to Memo fields using Clipper's DBU, then tried to reload the data into the new 
structure with the new type.  The documentation says that this should work just 
fine; i.e. it should load the old data stored as Character type into the new 
field and store it as Memo type.  This did not work.  I continually got empty 
Memo fields where before there was Character data.  I was using dBASE IV to 
reload the data since I was doing it on a machine that does not have DBU
(I was converting the database on this machine to the new structure which
was developed on another machine).

Also - using dBASE IV to convert the structure resulted in a new database that
Clipper would not recognize - Memo fields empty or not.  I had to use Clipper's
DBU to convert the database (which, I think, still resulted in lost Character
data - I forget).

Of course -------- this particular database has more fields than dBASE allows.
But this did not present a problem before - I could still APPEND FROM, BROWSE,
etc. before when I had more fields than dBASE allowed but was not introducing
Memo fields.  The only thing it wouldn't let me do that I could see was
actually modify the structure - it would consider it an invalid structure.

A slight incompatibility here????

-- 
    ---{john hayes}  Old Dominion University; Norfolk, Virginia USA
                     internet: aiko@cs.odu.edu
                     Home: (804) 622-8348     Work: (804) 460-2241 ext 134  

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