[quote]i tested it again.
the error occurs if a blob field is not empty.[/quote]
I can't reproduce this, but we'll investigate further.

[quote]furthermore i've seen ,that you can write data in the blob column (if empty) by writing in a blob-dbgrid-cell. you can see before "(HugeBlob)" and after "(HUGEBLOB)". Is this an error or a feature.[/quote]
This is a Delphi TDBGrid feature. Null fields are displayed as <Fieldname> and non-null fields are displayed as <FIELDNAME>.