Function print_key

src/jrd/btr.cpp:6460–6521

string print_key(thread_db* tdbb, jrd_rel* relation, index_desc* idx, Record* record)
{
/**************************************
 *
 *	p r i n t _ k e y
 *
 **************************************
 *
 * Functional description
 *	Convert index key into textual representation.
 *
 **************************************/
	fb_assert(relation && idx && record);

	if (!(relation->rel_flags & REL_scanned) ||
		(relation->rel_flags & REL_being_scanned))
	{
		MET_scan_relation(tdbb, relation);
	}

	const FB_SIZE_T MAX_KEY_STRING_LEN = 250;
	string key, value;

	try
	{
		if (idx->idx_flags & idx_expression)
		{
			const auto desc = BTR_eval_expression(tdbb, idx, record);
			value = DescPrinter(tdbb, desc, MAX_KEY_STRING_LEN, CS_METADATA).get();
			key += "<expression> = " + value;
		}
		else
		{
			for (USHORT i = 0; i < idx->idx_count; i++)
			{
				const USHORT field_id = idx->idx_rpt[i].idx_field;
				const jrd_fld* const field = MET_get_field(relation, field_id);

				if (field)
					value.printf("\"%s\"", field->fld_name.c_str());
				else
					value.printf("<field #%d>", field_id);

				key += value;

				dsc desc;
				const bool notNull = EVL_field(relation, record, field_id, &desc);
				value = DescPrinter(tdbb, notNull ? &desc : NULL, MAX_KEY_STRING_LEN, CS_METADATA).get();
				key += " = " + value;

				if (i < idx->idx_count - 1)
					key += ", ";
			}
		}
	}
	catch (const Exception&)
	{
		return "";