diff --git a/Data/include/Poco/Data/Extraction.h b/Data/include/Poco/Data/Extraction.h
index 476e8d7d4..985d3bd47 100644
--- a/Data/include/Poco/Data/Extraction.h
+++ b/Data/include/Poco/Data/Extraction.h
@@ -220,6 +220,11 @@ public:
 		return new Preparation<T>(pPrep, pos, _default);
 	}
 
+	void reset()
+	{
+		_nulls.clear();
+	}
+
 protected:
 
 	const std::vector<T>& result() const
@@ -306,6 +311,11 @@ public:
 		return new Preparation<bool>(pPrep, pos, _default);
 	}
 
+	void reset()
+	{
+		_nulls.clear();
+	}
+
 protected:
 
 	const std::vector<bool>& result() const
@@ -390,6 +400,11 @@ public:
 		return new Preparation<T>(pPrep, pos, _default);
 	}
 
+	void reset()
+	{
+		_nulls.clear();
+	}
+
 protected:
 
 	const std::list<T>& result() const
@@ -474,6 +489,11 @@ public:
 		return new Preparation<T>(pPrep, pos, _default);
 	}
 
+	void reset()
+	{
+		_nulls.clear();
+	}
+
 protected:
 
 	const std::deque<T>& result() const
@@ -522,6 +542,7 @@ public:
 
 	void reset()
 	{
+		Extraction<C>::reset();
 		_pColumn->reset();
 	}