Fetch driver function fails when segmented field (BLOB) located at beginning

Fetch driver function fails when segmented field (BLOB or CLOB field in
database) is located at beginning.

In case a segmented field is located at the beginning of an entity then the
following error shows up, after the fetch has been performed, when using Oracle:

I/O function: F, mode: 1, on file/table: <TABLE> index: 0 =
ORACLE Driver Error [-62]: Data was truncated on fetch.
ORACLE Driver Error [-35]: Fetch driver function failed.

When using Microsoft SQL Server then the following error is visible in the
message frame after the fetch:

I/O function: F, mode: 1, on file/table: <TABLE> index: 0 =
07009 [Microsoft][SQL Native Client]Invalid Descriptor Index