A table in one of my applications encountered the dreaded 'can't add rows to the table problem', which, judging by the many posts I have read on the topic here, is a well known vfp problem. I am hoping to clarify some of the issues surrounding this type of corruption, and determining the best strategy for avoiding it/fixing it in the future.

Here is a summary of the problem:

1) Uon save of a transaction in the system, rows were not being added to the table 'respmatr'.

2) Initially I thought it was a failure with one or more 'append from' commands. (I posted separately on the possible issues with append from in the past few days.)

3) Debugging the application revealed the following:
Respmatr started out with 610 rows. Table buffering was 5 for respmatr. The following commands were issued:

begin transaction
(do some other stuff)

select respmatr
append from dbf('currespmatr')
**respmatr is a table
**currespmatr is a cursor created with create cursor command - currespmatr always has **29 rows
browse nomod && shows the added rows, and record count shows as 639
llretval=tableupdate(.t.,.t.'respmatr') && llretval is true
end transaction
end the application
open respmatr and browse it - record count is 610. (no buffering)
** so at this point I suspect table header corruption - have seen it before. So I:
append a blank from the command window - it works. Now, for the time being, I think my table header corruption theory is shot.

But just to be sure I did the following:

copy the table data to a temp table
drop table respmatr
rebuild the table structure from scratch
append the rows back in.
repeat the debug process

After this the rows were added properly



More on environment:
VFP6, Win2k Professional – svc pack 1

Further discussion with the client revealed that prior to this there was a system crash – blue screen of death upon ejecting CD from CD drive

My questions are as follows:

1) I have seen other posts on here regarding this PARTICULAR type of corruption, ie. that rows can’t be added to the table. Will foxfix or sdt or recover find/fix THIS PARTICULAR TYPE OF corruption? Which is better?
(I seem to recall that in the past, when I had this type of corruption that the tools I had at the time did NOT detect it)
2) Why does the problem only show up when buffering is on and/or when in a transaction (I have seen other posts describing similar circumstance). What is the specific nature of the header problem?

3) Are any of these issues addressed/resolved with service packs?

4) Are there any win2k (only) settings that minimize the likelihood of the occurrence – e.g caching.

5) Can any of these problems be avoided by avoiding buffering and/or transactions? Can this happen WITHOUT a system crash?, e.g. is it related to buffering technique, or particular commands – e.g. insert into vs append blank vs append from?

Any ideas, experiences etc. would be greatly appreciated

TIA