diff -r 9172bd97ae99 -r 6f15f18d2abf src/FileAttributeFinder.h
--- a/src/FileAttributeFinder.h	Mon Nov 11 14:42:13 2019 +0100
+++ b/src/FileAttributeFinder.h	Sat Jan 11 00:56:51 2020 +0100
@@ -145,7 +145,7 @@
 	static const string_t FIELD_GROUP;
 	static const string_t FIELD_CONTENT;
 
-	virtual vector<AttributeMetadata> toMetadata(const RequestedField& field) override {
+	virtual vector<AttributeMetadata> toMetadata(RelationalWriter* writer, const RequestedField& field) override {
 		if (field.group == RequestedField::GROUP_FILE) {
 			vector<AttributeMetadata> metadata;
 			for (string_t alias : field.getAliases()) {