#58 Possible blob corruption

[Anonymous]

Exported from Bugzilla, issue 4190.

--- Comment added on 12/16/02 11:04:44 AM ---
Roberto Nicchi

I found a scenario that take to the corruption of a table.

Dataset connected to a table.

A Tdbcombobox connect to the dataset

in the onclick event of the Tdbcombobox the table the following happens;

table saved

another record is created in the same table (the current record is
duplicated using other Tfftable components)

locate in the table to find the new cloned record

the table is set in edit mode

a Blobmemo field value is changed

the table is saved

trying to open the table with FFexplorer gives error code 11896

the Sean FFVerify can to repare it
The log is:

Repairing file header
Repairing blocks
Block 1 (19): Index header row 0 specifies the index contains 8 keys but
there are 3 records in the table.
Block 1 (19): Index header row 1 specifies the index contains 5 keys but
there are 3 records in the table.
Block 1 (19): Index header row 2 specifies the index contains 5 keys but
there are 3 records in the table.
Block 1 (19): Index header row 3 specifies the index contains 5 keys but
there are 3 records in the table.
Block 1 (19): Index header row 4 specifies the index contains 5 keys but
there are 3 records in the table.
Block 1 (19): Index header row 5 specifies the index contains 5 keys but
there are 3 records in the table.
Block 4 (34): The BLOB is marked as deleted (BLOB field "Note", BLOB
refnum 0:12892, key fields: Anno: 2002; Numero: 7, record 6 of data block
4)
..Block 4 (34): BLOB reference set to null (field "Note", key fields:
[Anno: 2002; Numero: 7], record 6 of data block 4).
Block 4 (34): The BLOB is marked as deleted (BLOB field "Note", BLOB
refnum 0:12892, key fields: Anno: 2002; Numero: 8, record 7 of data block
4)
..Block 4 (34): BLOB reference set to null (field "Note", key fields:
[Anno: 2002; Numero: 8], record 7 of data block 4).
Block 4 (34): The BLOB is marked as deleted (BLOB field "Note", BLOB
refnum 0:12892, key fields: Anno: 2002; Numero: 9, record 8 of data block
4)
..Block 4 (34): BLOB reference set to null (field "Note", key fields:
[Anno: 2002; Numero: 9], record 8 of data block 4).
Repairing block chains
Packing
============================================================
Repair complete. Found 9 errors and repaired 3 errors. The table was
packed.
============================================================

If necessary i can work in a demo the show the error

Roberto Nicchi
MASTER INFORMATICA
ITALY
FF 2.13 beta 2

--- Comment added on 12/16/02 11:04:56 AM ---
it seems that the problem happens using a statement like this:

mytable.fieldbyname('memofield').asstring:=
'text inserted+#13+mytable.fieldbyname('memofield').asstring;

and only if the blob field already has a value

Roberto