Gets a field size in bytes.
[in] Request handle received in DatabasePrepare().
[in] Field index in the request. Field numbering starts from zero and cannot exceed DatabaseColumnsCount() - 1.
If successful, the field size in bytes is returned, otherwise -1. To get the error code, use GetLastError(), the possible responses are:
The value can be obtained only if at least one DatabaseRead() call has been preliminarily made for 'request'.