Gets a field name by index.
[in] Request handle received in DatabasePrepare().
[in] Field index in the request. Field numbering starts from zero and cannot exceed DatabaseColumnsCount() - 1.
[out] Variable for writing the field name.
Return true if successful, otherwise false. 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'.