null bindings and RecordSet::isNull (SQLite done and tested, ODBC todo)

Data/ODBC/include/Poco/Data/ODBC/Binder.h

@@ -125,12 +125,15 @@ public:
 	void bind(std::size_t pos, const std::string& val, Direction dir = PD_IN);
 		/// Binds a string.
 
-	void bind(std::size_t pos, const Poco::Data::BLOB& val, Direction dir = PD_IN);
-		/// Binds a BLOB.
+	void bind(std::size_t pos, const BLOB& val, Direction dir = PD_IN);
+		/// Binds a BLOB. In-bound only.
 
-	void bind(std::size_t pos, const Poco::DateTime& val, Direction dir = PD_IN);
+	void bind(std::size_t pos, const DateTime& val, Direction dir = PD_IN);
 		/// Binds a DateTime.
 
+	void bind(std::size_t pos, const NullData& val, Direction dir = PD_IN);
+		/// Binds a null. In-bound only.
+
 	void setDataBinding(ParameterBinding binding);
 		/// Set data binding type.
 
@@ -212,6 +215,10 @@ private:
 		}
 	}
 
+	void bindNull(std::size_t pos, SQLSMALLINT cDataType);
+		/// Utility function for binding null values.
+		/// For in-bound purposes only.
+
 	const StatementHandle& _rStmt;
 	LengthVec _lengthIndicator;
 	ParamMap _inParams;
@@ -298,6 +305,15 @@ inline void Binder::bind(std::size_t pos, const char& val, Direction dir)
 }
 
 
+inline void Binder::bind(std::size_t pos, const NullData& val, Direction dir)
+{
+	if (isOutBound(dir) || !isInBound(dir))
+		throw NotImplementedException("NULL parameter type can only be inbound.");
+
+	throw NotImplementedException("TODO");
+}
+
+
 inline void Binder::setDataBinding(Binder::ParameterBinding binding)
 {
 	_paramBinding = binding;

Data/ODBC/include/Poco/Data/ODBC/Extractor.h

@@ -127,6 +127,9 @@ public:
 	Preparation::DataExtraction getDataExtraction() const;
 		/// Returns data extraction mode.
 
+	bool isNull(std::size_t pos);
+		/// Returns true if the current row value at pos column is null.
+
 private:
 	static const int CHUNK_SIZE = 1024;
 		/// Amount of data retrieved in one SQLGetData() request when doing manual extract.
@@ -200,6 +203,12 @@ inline Preparation::DataExtraction Extractor::getDataExtraction() const
 }
 
 
+inline bool Extractor::isNull(std::size_t pos)
+{
+	throw NotImplementedException("TODO");
+}
+
+
 } } } // namespace Poco::Data::ODBC
 
 

Data/ODBC/src/Binder.cpp

@@ -216,6 +216,52 @@ void Binder::bind(std::size_t pos, const Poco::DateTime& val, Direction dir)
 }
 
 
+void Binder::bindNull(std::size_t pos, SQLSMALLINT cDataType)
+{
+	_inParams.insert(ParamMap::value_type(0, 0));
+
+	SQLLEN* pLenIn = new SQLLEN;
+	*pLenIn  = SQL_NULL_DATA;
+
+	if (PB_AT_EXEC == _paramBinding)
+		*pLenIn  = SQL_LEN_DATA_AT_EXEC(SQL_NULL_DATA);
+
+	_lengthIndicator.push_back(pLenIn);
+
+	SQLINTEGER colSize = 0;
+	SQLSMALLINT decDigits = 0;
+	
+	try
+	{
+		Parameter p(_rStmt, pos);
+		colSize = (SQLINTEGER) p.columnSize();
+		decDigits = (SQLSMALLINT) p.decimalDigits();
+	}catch (StatementException&)
+	{
+		try
+		{
+			ODBCColumn c(_rStmt, pos);
+			colSize = (SQLINTEGER) c.length();
+			decDigits = (SQLSMALLINT) c.precision();
+		}catch (StatementException&) { }
+	}
+
+	if (Utility::isError(SQLBindParameter(_rStmt, 
+		(SQLUSMALLINT) pos + 1, 
+		SQL_PARAM_INPUT, 
+		cDataType, 
+		Utility::sqlDataType(cDataType), 
+		colSize,
+		decDigits,
+		0, 
+		0, 
+		_lengthIndicator.back())))
+	{
+		throw StatementException(_rStmt, "SQLBindParameter()");
+	}
+}
+
+
 std::size_t Binder::parameterSize(SQLPOINTER pAddr) const
 {
 	ParamMap::const_iterator it = _inParams.find(pAddr);

Data/SQLite/include/Poco/Data/SQLite/Binder.h

@@ -63,57 +63,61 @@ public:
 	~Binder();
 		/// Destroys the Binder.
 
-	void bind(std::size_t pos, const Poco::Int8 &val, Direction dir);
+	void bind(std::size_t pos, const Poco::Int8 &val, Direction dir = PD_IN);
 		/// Binds an Int8.
 
-	void bind(std::size_t pos, const Poco::UInt8 &val, Direction dir);
+	void bind(std::size_t pos, const Poco::UInt8 &val, Direction dir = PD_IN);
 		/// Binds an UInt8.
 
-	void bind(std::size_t pos, const Poco::Int16 &val, Direction dir);
+	void bind(std::size_t pos, const Poco::Int16 &val, Direction dir = PD_IN);
 		/// Binds an Int16.
 
-	void bind(std::size_t pos, const Poco::UInt16 &val, Direction dir);
+	void bind(std::size_t pos, const Poco::UInt16 &val, Direction dir = PD_IN);
 		/// Binds an UInt16.
 
-	void bind(std::size_t pos, const Poco::Int32 &val, Direction dir);
+	void bind(std::size_t pos, const Poco::Int32 &val, Direction dir = PD_IN);
 		/// Binds an Int32.
 
-	void bind(std::size_t pos, const Poco::UInt32 &val, Direction dir);
+	void bind(std::size_t pos, const Poco::UInt32 &val, Direction dir = PD_IN);
 		/// Binds an UInt32.
 
-	void bind(std::size_t pos, const Poco::Int64 &val, Direction dir);
+	void bind(std::size_t pos, const Poco::Int64 &val, Direction dir = PD_IN);
 		/// Binds an Int64.
 
-	void bind(std::size_t pos, const Poco::UInt64 &val, Direction dir);
+	void bind(std::size_t pos, const Poco::UInt64 &val, Direction dir = PD_IN);
 		/// Binds an UInt64.
 
-	void bind(std::size_t pos, const bool &val, Direction dir);
+	void bind(std::size_t pos, const bool &val, Direction dir = PD_IN);
 		/// Binds a boolean.
 
-	void bind(std::size_t pos, const float &val, Direction dir);
+	void bind(std::size_t pos, const float &val, Direction dir = PD_IN);
 		/// Binds a float.
 
-	void bind(std::size_t pos, const double &val, Direction dir);
+	void bind(std::size_t pos, const double &val, Direction dir = PD_IN);
 		/// Binds a double.
 
-	void bind(std::size_t pos, const char &val, Direction dir);
+	void bind(std::size_t pos, const char &val, Direction dir = PD_IN);
 		/// Binds a single character.
 
-	void bind(std::size_t pos, const char* const &pVal, Direction dir);
+	void bind(std::size_t pos, const char* const &pVal, Direction dir = PD_IN);
 		/// Binds a const char ptr.
 
-	void bind(std::size_t pos, const std::string& val, Direction dir);
+	void bind(std::size_t pos, const std::string& val, Direction dir = PD_IN);
 		/// Binds a string.
 
-	void bind(std::size_t pos, const Poco::Data::BLOB& val, Direction dir);
+	void bind(std::size_t pos, const Poco::Data::BLOB& val, Direction dir = PD_IN);
 		/// Binds a BLOB.
 
-	void bind(std::size_t pos, const DateTime& val, Direction dir);
+	void bind(std::size_t pos, const DateTime& val, Direction dir = PD_IN);
 		/// Binds a DateTime.
 
+	void bind(std::size_t pos, const NullData& val, Direction dir = PD_IN);
+		/// Binds a null.
+
 private:
 	void checkReturn(int rc);
-		/// Checks the SQLite return code and throws an appropriate exception.
+		/// Checks the SQLite return code and throws an appropriate exception
+		/// if error has occurred.
 
 	sqlite3_stmt* _pStmt;
 };

Data/SQLite/include/Poco/Data/SQLite/Extractor.h

@@ -43,6 +43,8 @@
 #include "Poco/Data/SQLite/SQLite.h"
 #include "Poco/Data/AbstractExtractor.h"
 #include "Poco/Any.h"
+#include <vector>
+#include <utility>
 
 
 struct sqlite3_stmt;
@@ -58,6 +60,9 @@ class SQLite_API Extractor: public Poco::Data::AbstractExtractor
 	/// If NULL is received, the incoming val value is not changed and false is returned
 {
 public:
+	typedef std::vector<std::pair<bool, bool> > NullIndVec;
+		/// Type for null indicators container.
+
 	Extractor(sqlite3_stmt* pStmt);
 		/// Creates the Extractor.
 
@@ -112,14 +117,38 @@ public:
 	bool extract(std::size_t pos, Poco::Any& val);
 		/// Extracts an Any.
 
-private:
 	bool isNull(std::size_t pos);
-		/// Returns true if a non null value can be extracted
+		/// Returns true if the current row value at pos column is null.
+		/// Because of the loss of information about null-ness of the 
+		/// underlying database values due to the nature of SQLite engine, 
+		/// (once null value is converted to default value, SQLite API 
+		/// treats it  as non-null), a null indicator container member
+		/// variable is used to cache the indicators of the underlying nulls 
+		/// thus rendering this function idempotent. 
+		/// The container is a vector of [bool, bool] pairs.
+		/// The vector index corresponds to the column position, the first
+		/// bool value in the pair is true if the null indicator has 
+		/// been set and the second bool value in the pair is true if
+		/// the column is actually null.
 
+	void reset();
+		/// Clears the cached nulls indicator vector.
+
+private:
 	sqlite3_stmt* _pStmt;
+	NullIndVec _nulls;
 };
 
 
+///
+/// inlines
+///
+inline void Extractor::reset()
+{
+	_nulls.clear();
+}
+
+
 } } } // namespace Poco::Data::SQLite
 
 

Data/SQLite/src/Binder.cpp

@@ -110,6 +110,12 @@ void Binder::bind(std::size_t pos, const DateTime& val, Direction dir)
 }
 
 
+void Binder::bind(std::size_t pos, const NullData&, Direction)
+{
+	sqlite3_bind_null(_pStmt, pos);
+}
+
+
 void Binder::checkReturn(int rc)
 {
 	if (rc != SQLITE_OK)

Data/SQLite/src/Extractor.cpp

@@ -313,7 +313,16 @@ bool Extractor::extract(std::size_t pos, Poco::Any& val)
 
 bool Extractor::isNull(std::size_t pos)
 {
-	return sqlite3_column_type(_pStmt, (int) pos) == SQLITE_NULL;
+	if (pos >= _nulls.size())
+		_nulls.resize(pos + 1);
+
+	if (!_nulls[pos].first)
+	{
+		_nulls[pos].first = true;
+		_nulls[pos].second = (SQLITE_NULL == sqlite3_column_type(_pStmt, pos));
+	}
+	
+	return _nulls[pos].second;
 }
 
 

Data/SQLite/src/SQLiteStatementImpl.cpp

@@ -185,6 +185,8 @@ bool SQLiteStatementImpl::hasNext()
 
 	_stepCalled   = true;
 	_nextResponse = sqlite3_step(_pStmt);
+	_pExtractor->reset();//to clear the cached null indicators
+
 	if (_nextResponse != SQLITE_ROW && _nextResponse != SQLITE_OK && _nextResponse != SQLITE_DONE)
 	{
 		Utility::throwException(_nextResponse);

Data/SQLite/testsuite/src/SQLiteTest.cpp

@@ -38,13 +38,12 @@
 #include "Poco/Data/Statement.h"
 #include "Poco/Data/RecordSet.h"
 #include "Poco/Data/SQLite/Connector.h"
+#include "Poco/Data/SQLite/SQLiteException.h"
 #include "Poco/Data/TypeHandler.h"
 #include "Poco/Tuple.h"
 #include "Poco/Any.h"
 #include "Poco/Exception.h"
 #include <iostream>
-#include "Poco/File.h"
-#include "Poco/Stopwatch.h"
 
 
 using namespace Poco::Data;
@@ -54,7 +53,7 @@ using Poco::AnyCast;
 using Poco::InvalidAccessException;
 using Poco::RangeException;
 using Poco::BadCastException;
-
+using Poco::Data::SQLite::InvalidSQLStatementException;
 
 struct Person
 {
@@ -187,6 +186,9 @@ void SQLiteTest::testSimpleAccess()
 	assert (lastName == result);
 	tmp << "SELECT Age FROM PERSON", into(count), now;
 	assert (count == age);
+	tmp << "UPDATE PERSON SET Age = -1", now;
+	tmp << "SELECT Age FROM PERSON", into(age), now;
+	assert (-1 == age);
 	tmp.close();
 	assert (!tmp.isConnected());
 }
@@ -1610,6 +1612,68 @@ void SQLiteTest::testPrimaryKeyConstraint()
 }
 
 
+void SQLiteTest::testNull()
+{
+	Session ses (SessionFactory::instance().create(SQLite::Connector::KEY, "dummy.db"));
+	ses << "DROP TABLE IF EXISTS NullTest", now;
+
+	ses << "CREATE TABLE NullTest (i INTEGER NOT NULL)", now;
+
+	try
+	{
+		ses << "INSERT INTO NullTest VALUES(:i)", use(null), now;
+		fail ("must fail");
+	}catch (InvalidSQLStatementException&) { }
+
+	ses << "DROP TABLE IF EXISTS NullTest", now;
+	ses << "CREATE TABLE NullTest (i INTEGER, r REAL, v VARCHAR)", now;
+
+	ses << "INSERT INTO NullTest VALUES(:i, :r, :v)", use(null), use(null), use(null), now;
+	
+	RecordSet rs(ses, "SELECT * FROM NullTest");
+	rs.moveFirst();
+	assert (rs.isNull("i"));
+	assert (rs["i"] == 0);
+	assert (rs.isNull("r"));
+	assert (rs.isNull("v"));
+	assert (rs["v"] == "");
+
+	ses << "DROP TABLE IF EXISTS NullTest", now;
+	ses << "CREATE TABLE NullTest (i INTEGER, r REAL, v VARCHAR)", now;
+	int i = 1;
+	double f = 1.2;
+	std::string s = "123";
+
+	ses << "INSERT INTO NullTest (i, r, v) VALUES (:i, :r, :v)", use(i), use(f), use(s), now;
+	rs = (ses << "SELECT * FROM NullTest", now);
+	rs.moveFirst();
+	assert (!rs.isNull("i"));
+	assert (rs["i"] == 1);
+	assert (!rs.isNull("v"));
+	assert (!rs.isNull("r"));
+	assert (rs["v"] == "123");
+	
+	ses << "UPDATE NullTest SET v = :n WHERE i == :i", use(null), use(i), now;
+	i = 2;
+	f = 3.4;
+	ses << "INSERT INTO NullTest (i, r, v) VALUES (:i, :r, :v)", use(i), use(null), use(null), now;
+	rs = (ses << "SELECT i, r, v FROM NullTest ORDER BY i ASC", now);
+	rs.moveFirst();
+	assert (!rs.isNull("i"));
+	assert (rs["i"] == 1);
+	assert (!rs.isNull("r"));
+	assert (rs.isNull("v"));
+	assert (rs["v"] == "");
+
+	assert (rs.moveNext());
+	assert (!rs.isNull("i"));
+	assert (rs["i"] == 2);
+	assert (rs.isNull("r"));
+	assert (rs.isNull("v"));
+	assert (rs["v"] == "");
+}
+
+
 void SQLiteTest::setUp()
 {
 }
@@ -1682,6 +1746,7 @@ CppUnit::Test* SQLiteTest::suite()
 	CppUnit_addTest(pSuite, SQLiteTest, testTupleVector1);
 	CppUnit_addTest(pSuite, SQLiteTest, testInternalExtraction);
 	CppUnit_addTest(pSuite, SQLiteTest, testPrimaryKeyConstraint);
+	CppUnit_addTest(pSuite, SQLiteTest, testNull);
 
 	return pSuite;
 }

Data/SQLite/testsuite/src/SQLiteTest.h

@@ -110,6 +110,7 @@ public:
 
 	void testInternalExtraction();
 	void testPrimaryKeyConstraint();
+	void testNull();
 
 	void setUp();
 	void tearDown();

Data/include/Poco/Data/AbstractBinder.h

@@ -46,15 +46,32 @@
 
 namespace Poco {
 
-
 class DateTime;
 
-
 namespace Data {
 
-
 class BLOB;
 
+enum NullData
+{
+	NULL_GENERIC = 0,
+	NULL_INT8,
+	NULL_UINT8,
+	NULL_INT16,
+	NULL_UINT16,
+	NULL_INT32,
+	NULL_UINT32,
+	NULL_INT64,
+	NULL_UINT64,
+	NULL_FLOAT,
+	NULL_DOUBLE,
+	NULL_STRING,
+	NULL_BLOB
+};
+
+
+static const NullData null = NULL_GENERIC;
+
 
 class Data_API AbstractBinder
 	/// Interface for Binding data types to placeholders. The default placeholder format 
@@ -123,6 +140,9 @@ public:
 	virtual void bind(std::size_t pos, const DateTime& val, Direction dir) = 0;
 		/// Binds a DateTime.
 
+	virtual void bind(std::size_t pos, const NullData& val, Direction dir) = 0;
+		/// Binds a null.
+
 	static bool isOutBound(Direction dir);
 		/// Returns true if direction is out bound;
 

Data/include/Poco/Data/AbstractExtraction.h

@@ -106,6 +106,14 @@ public:
 	Poco::UInt32 getLimit() const;
 		/// Gets the limit.
 
+	virtual bool isNull(std::size_t row) const;
+		/// In implementations, this function returns true if value at row is null, 
+		/// false otherwise. 
+		/// Normal behavior is to replace nulls with default values.
+		/// However, extraction implementations may remember the underlying database
+		/// null values and be able to later provide information about them.
+		/// Here, this function throws NotImplementedException.
+
 private:
 	AbstractExtractor* _pExtractor;
 	Poco::UInt32       _limit;
@@ -143,6 +151,12 @@ inline Poco::UInt32 AbstractExtraction::getLimit() const
 }
 
 
+inline bool AbstractExtraction::isNull(std::size_t row) const
+{
+	throw NotImplementedException("Check for null values not implemented.");
+}
+
+
 } } // namespace Poco::Data
 
 

Data/include/Poco/Data/AbstractExtractor.h

@@ -111,9 +111,25 @@ public:
 
 	virtual bool extract(std::size_t pos, DateTime& val) = 0;
 		/// Extracts a DateTime. Returns false if null was received.
+
+	virtual bool isNull(std::size_t pos) = 0;
+		/// Returns true if the current row value at pos column is null.
+
+	virtual void reset();
+		/// Resets any information internally cached by the extractor.
+		/// (e.g. info about underlying DB null values)
 };
 
 
+///
+/// inlines
+///
+inline void AbstractExtractor::reset()
+{
+	//default no-op
+}
+
+
 } } // namespace Poco::Data
 
 

Data/include/Poco/Data/Extraction.h

@@ -93,11 +93,18 @@ public:
 		return 1u;
 	}
 
+	bool isNull(std::size_t row = 0) const
+	{
+		return _null;
+	}
+
 	void extract(std::size_t pos)
 	{
 		if (_extracted) throw ExtractException("value already extracted");
 		_extracted = true;
-		TypeHandler<T>::extract(pos, _rResult, _default, getExtractor());
+		AbstractExtractor* pExt = getExtractor();
+		TypeHandler<T>::extract(pos, _rResult, _default, pExt);
+		_null = pExt->isNull(pos);
 	}
 
 	void reset()
@@ -114,6 +121,7 @@ private:
 	T&   _rResult;
 	T    _default;   // copy the default
 	bool _extracted;
+	bool _null;
 };
 
 
@@ -149,10 +157,23 @@ public:
 		return getLimit();
 	}
 
+	bool isNull(std::size_t row) const
+	{
+		try
+		{
+			return _nulls.at(row);
+		}catch (std::out_of_range& ex)
+		{ 
+			throw RangeException(ex.what()); 
+		}
+	}
+
 	void extract(std::size_t pos)
 	{
+		AbstractExtractor* pExt = getExtractor();
 		_rResult.push_back(_default);
-		TypeHandler<T>::extract(pos, _rResult.back(), _default, getExtractor());
+		TypeHandler<T>::extract(pos, _rResult.back(), _default, pExt);
+		_nulls.push_back(pExt->isNull(pos));
 	}
 
 	virtual void reset()
@@ -174,6 +195,7 @@ protected:
 private:
 	std::vector<T>&  _rResult;
 	T                _default; // copy the default
+	std::deque<bool> _nulls;
 };
 
 
@@ -209,10 +231,23 @@ public:
 		return getLimit();
 	}
 
+	bool isNull(std::size_t row) const
+	{
+		try
+		{
+			return _nulls.at(row);
+		}catch (std::out_of_range& ex)
+		{ 
+			throw RangeException(ex.what()); 
+		}
+	}
+
 	void extract(std::size_t pos)
 	{
+		AbstractExtractor* pExt = getExtractor();
 		_rResult.push_back(_default);
-		TypeHandler<T>::extract(pos, _rResult.back(), _default, getExtractor());
+		TypeHandler<T>::extract(pos, _rResult.back(), _default, pExt);
+		_nulls.push_back(pExt->isNull(pos));
 	}
 
 	virtual void reset()
@@ -234,6 +269,7 @@ protected:
 private:
 	std::list<T>&    _rResult;
 	T                _default; // copy the default
+	std::deque<bool> _nulls;
 };
 
 
@@ -269,10 +305,23 @@ public:
 		return getLimit();
 	}
 
+	bool isNull(std::size_t row) const
+	{
+		try
+		{
+			return _nulls.at(row);
+		}catch (std::out_of_range& ex)
+		{ 
+			throw RangeException(ex.what()); 
+		}
+	}
+
 	void extract(std::size_t pos)
 	{
+		AbstractExtractor* pExt = getExtractor();
 		_rResult.push_back(_default);
-		TypeHandler<T>::extract(pos, _rResult.back(), _default, getExtractor());
+		TypeHandler<T>::extract(pos, _rResult.back(), _default, pExt);
+		_nulls.push_back(pExt->isNull(pos));
 	}
 
 	virtual void reset()
@@ -294,6 +343,7 @@ protected:
 private:
 	std::deque<T>&   _rResult;
 	T                _default; // copy the default
+	std::deque<bool> _nulls;
 };
 
 
@@ -341,6 +391,11 @@ public:
 		}
 	}
 
+	bool isNull(std::size_t row) const
+	{
+		return Extraction<C>::isNull(row);
+	}
+
 	const Column<T,C>& column() const
 	{
 		return *_pColumn;

Data/include/Poco/Data/RecordSet.h

@@ -53,6 +53,9 @@ namespace Poco {
 namespace Data {
 
 
+class Session;
+
+
 class Data_API RecordSet: private Statement
 	/// RecordSet provides access to data returned from a query.
 	/// Data access indexes (row and column) are 0-based, as usual in C++.
@@ -73,9 +76,14 @@ class Data_API RecordSet: private Statement
 	/// a limit for the Statement.
 {
 public:
+	using Statement::isNull;
+
 	explicit RecordSet(const Statement& rStatement);
 		/// Creates the RecordSet.
 
+	explicit RecordSet(Session& rSession, const std::string& query);
+		/// Creates the RecordSet.
+
 	~RecordSet();
 		/// Destroys the RecordSet.
 
@@ -223,6 +231,9 @@ public:
 		/// Returns column precision for the column with specified name.
 		/// Valid for floating point fields only (zero for other data types).
 
+	bool isNull(const std::string& name);
+		/// Returns true if column value of the current row is null.
+
 private:
 	RecordSet();
 
@@ -273,7 +284,7 @@ inline std::size_t RecordSet::columnCount() const
 
 inline Statement& RecordSet::operator = (const Statement& stmt)
 {
-	_currentRow = 1;
+	_currentRow = 0;
 	return Statement::operator = (stmt);
 }
 
@@ -344,6 +355,12 @@ inline std::size_t RecordSet::columnPrecision(const std::string& name)const
 }
 
 
+inline bool RecordSet::isNull(const std::string& name)
+{
+	return isNull(metaColumn(name).position(), _currentRow);
+}
+
+
 } } // namespace Poco::Data
 
 

Data/include/Poco/Data/Statement.h

@@ -168,6 +168,9 @@ protected:
 	const MetaColumn& metaColumn(const std::string& name) const;
 		/// Returns the type for the column with specified name.
 
+	 bool isNull(std::size_t col, std::size_t row);
+		/// Returns true if the current row value at column pos is null.
+
 private:
 	typedef Poco::SharedPtr<StatementImpl> StatementImplPtr;
 
@@ -269,6 +272,12 @@ inline Statement::Storage Statement::storage() const
 }
 
 
+inline bool Statement::isNull(std::size_t col, std::size_t row)
+{
+	return _ptr->isNull(col, row);
+}
+
+
 } } // namespace Poco::Data
 
 

Data/include/Poco/Data/StatementImpl.h

@@ -299,6 +299,9 @@ private:
 			addExtract(createExtract<T, std::deque<T> >(mc));
 	}
 
+	bool isNull(std::size_t col, std::size_t row);
+		/// Returns true if the value in [col, row] is null.
+		
 	StatementImpl(const StatementImpl& stmt);
 	StatementImpl& operator = (const StatementImpl& stmt);
 
@@ -403,6 +406,18 @@ inline bool StatementImpl::isStoredProcedure() const
 }
 
 
+inline bool StatementImpl::isNull(std::size_t col, std::size_t row)
+{
+	try 
+	{
+		return extractions().at(col)->isNull(row);
+	}catch (std::out_of_range& ex)
+	{ 
+		throw RangeException(ex.what()); 
+	}
+}
+
+
 } } // namespace Poco::Data
 
 

Data/src/RecordSet.cpp

@@ -35,6 +35,7 @@
 
 
 #include "Poco/Data/RecordSet.h"
+#include "Poco/Data/Session.h"
 
 
 namespace Poco {
@@ -48,6 +49,13 @@ RecordSet::RecordSet(const Statement& rStatement):
 }
 
 
+RecordSet::RecordSet(Session& rSession, const std::string& query): 
+	Statement((rSession << query, now)),
+	_currentRow(0)
+{
+}
+
+
 RecordSet::~RecordSet()
 {
 }

Data/testsuite/src/Binder.cpp

@@ -120,12 +120,17 @@ void Binder::bind(std::size_t pos, const std::string& val, Direction dir)
 }
 
 
-void Binder::bind(std::size_t pos, const Poco::Data::BLOB& val, Direction dir)
+void Binder::bind(std::size_t pos, const BLOB& val, Direction dir)
 {
 }
 
 
-void Binder::bind(std::size_t pos, const Poco::DateTime& val, Direction dir)
+void Binder::bind(std::size_t pos, const DateTime& val, Direction dir)
+{
+}
+
+
+void Binder::bind(std::size_t pos, const NullData& val, Direction dir)
 {
 }
 

Data/testsuite/src/Binder.h

@@ -96,10 +96,13 @@ public:
 	void bind(std::size_t pos, const std::string& val, Direction dir = PD_IN);
 		/// Binds a string.
 
-	void bind(std::size_t pos, const Poco::Data::BLOB& val, Direction dir = PD_IN);
+	void bind(std::size_t pos, const BLOB& val, Direction dir = PD_IN);
 		/// Binds a BLOB.
 
-	void bind(std::size_t pos, const Poco::DateTime& val, Direction dir = PD_IN);
+	void bind(std::size_t pos, const DateTime& val, Direction dir = PD_IN);
+		/// Binds a DateTime.
+
+	void bind(std::size_t pos, const NullData& val, Direction dir = PD_IN);
 		/// Binds a DateTime.
 
 	void reset();

Data/testsuite/src/Extractor.h

@@ -99,6 +99,9 @@ public:
 	bool extract(std::size_t pos, Poco::DateTime& val);
 		/// Extracts a DateTime.
 
+	bool isNull(std::size_t pos);
+		/// Returns true if the current row value at pos column is null.
+
 	void reset();
 };
 
@@ -108,6 +111,12 @@ inline void Extractor::reset()
 }
 
 
+inline bool Extractor::isNull(std::size_t pos)
+{
+	return false;
+}
+
+
 } } } // namespace Poco::Data::Test