Function iscArrayLookupDescImpl

src/yvalve/array.cpp:193–263

void iscArrayLookupDescImpl(Why::YAttachment* attachment,
	Why::YTransaction* transaction, const SCHAR* relationName, const SCHAR* fieldName, ISC_ARRAY_DESC* desc,
	MetaString* globalField)
{
	LocalStatus status;
	CheckStatusWrapper statusWrapper(&status);

	copy_exact_name(fieldName, desc->array_desc_field_name, sizeof(desc->array_desc_field_name));
	copy_exact_name(relationName, desc->array_desc_relation_name, sizeof(desc->array_desc_relation_name));

	desc->array_desc_flags = 0;

	constexpr auto sql = R"""(
		select f.rdb$field_name,
		       f.rdb$field_type,
		       f.rdb$field_scale,
		       f.rdb$field_length,
		       f.rdb$dimensions
		    from rdb$relation_fields rf
		    join rdb$fields f
		      on f.rdb$field_name = rf.rdb$field_source
		    where rf.rdb$relation_name = ? and
		          rf.rdb$field_name = ?
	)""";

	FB_MESSAGE(InputMessage, CheckStatusWrapper,
		(FB_VARCHAR(MAX_SQL_IDENTIFIER_LEN), relationName)
		(FB_VARCHAR(MAX_SQL_IDENTIFIER_LEN), fieldName)
	) inputMessage(&statusWrapper, MasterInterfacePtr());
	inputMessage.clear();

	FB_MESSAGE(OutputMessage, CheckStatusWrapper,
		(FB_VARCHAR(MAX_SQL_IDENTIFIER_LEN), fieldName)
		(FB_INTEGER, fieldType)
		(FB_INTEGER, fieldScale)
		(FB_INTEGER, fieldLength)
		(FB_INTEGER, dimensions)
	) outputMessage(&statusWrapper, MasterInterfacePtr());

	inputMessage->relationNameNull = FB_FALSE;
	inputMessage->relationName.set((const char*) relationName);

	inputMessage->fieldNameNull = FB_FALSE;
	inputMessage->fieldName.set((const char*) fieldName);

	auto resultSet = makeNoIncRef(attachment->openCursor(&statusWrapper, transaction, 0, sql,
		SQL_DIALECT_CURRENT, inputMessage.getMetadata(), inputMessage.getData(),
		outputMessage.getMetadata(), nullptr, 0));
	status.check();

	if (resultSet->fetchNext(&statusWrapper, outputMessage.getData()) == IStatus::RESULT_OK)
	{
		if (globalField)
			globalField->assign(outputMessage->fieldName.str, outputMessage->fieldName.length);

		desc->array_desc_dtype = outputMessage->fieldTypeNull ? 0 : outputMessage->fieldType;
		desc->array_desc_scale = outputMessage->fieldScaleNull ? 0 : outputMessage->fieldScale;
		desc->array_desc_length = outputMessage->fieldLengthNull ? 0 : outputMessage->fieldLength;