* Use sqlite3_stmt_readonly to determine if sqlite3_changes should be called

* Remove sys.dual dependency, improving multi-threaded applications

Data/SQLite/src/SQLiteStatementImpl.cpp

@@ -80,26 +80,11 @@ void SQLiteStatementImpl::compileImpl()
 {
 	if (!_pLeftover)
 	{
-		// Executed to force reset of previous changes count to zero.
-		// Without this, execute() will not return accurate (zero) count if select 
-		// statement returns no results previous [insert|update|delete] affected rows.
-		if (sqlite3_changes(_pDB))
-		{
-			if (SQLITE_OK != sqlite3_exec(_pDB, "delete from sys.dual where 1 <> 1;", 0, 0, 0))
-				throw ExecutionException("Error updating system database.");
-		}
 		_bindBegin = bindings().begin();
 	}
 
 	std::string statement(toString());
 
-	if (isubstr(statement, std::string("drop")) != istring::npos &&
-		isubstr(statement, std::string("table")) != istring::npos &&
-		isubstr(statement, std::string("dual")) != istring::npos)
-	{
-		throw InvalidAccessException("Cannot drop system table!");
-	}
-
 	sqlite3_stmt* pStmt = 0;
 	const char* pSql = _pLeftover ? _pLeftover->c_str() : statement.c_str();
 
@@ -271,7 +256,8 @@ bool SQLiteStatementImpl::hasNext()
 	_nextResponse = sqlite3_step(_pStmt);
 
 	if (_affectedRowCount == POCO_SQLITE_INV_ROW_CNT) _affectedRowCount = 0;
-	_affectedRowCount += sqlite3_changes(_pDB);
+	if (!sqlite3_stmt_readonly(_pStmt))
+		_affectedRowCount += sqlite3_changes(_pDB);
 
 	if (_nextResponse != SQLITE_ROW && _nextResponse != SQLITE_OK && _nextResponse != SQLITE_DONE)
 		Utility::throwException(_nextResponse);
@@ -331,7 +317,8 @@ const MetaColumn& SQLiteStatementImpl::metaColumn(std::size_t pos) const
 
 std::size_t SQLiteStatementImpl::affectedRowCount() const
 {
-	return _affectedRowCount != POCO_SQLITE_INV_ROW_CNT ? _affectedRowCount : sqlite3_changes(_pDB);
+	if (_affectedRowCount != POCO_SQLITE_INV_ROW_CNT) return _affectedRowCount;
+	return _pStmt == 0 || sqlite3_stmt_readonly(_pStmt) ? 0 : sqlite3_changes(_pDB);
 }
 
 

Data/SQLite/src/SessionImpl.cpp

@@ -195,14 +195,6 @@ void SessionImpl::open(const std::string& connect)
 		throw ConnectionFailedException(ex.displayText());
 	}
 
-	if (SQLITE_OK != sqlite3_exec(_pDB,
-		"attach database ':memory:' as sys;"
-		"create table sys.dual (dummy);", 
-		0, 0, 0))
-	{
-		throw ExecutionException("Cannot create system database.");
-	}
-
 	_connected = true;
 }
 

Data/SQLite/testsuite/src/SQLiteTest.cpp

@@ -2557,55 +2557,6 @@ void SQLiteTest::testReconnect()
 }
 
 
-void SQLiteTest::testSystemTable()
-{
-	Session session (Poco::Data::SQLite::Connector::KEY, "dummy.db");
-	int cntFile = 0;
-	session << "DROP TABLE IF EXISTS Test", now;
-	session << "CREATE TABLE Test (Test INTEGER)", now;
-	session << "INSERT INTO Test VALUES (1)", now;
-	session << "SELECT count(*) FROM Test", into(cntFile), now;
-	assert (1 == cntFile);
-
-	int cntMem = -1;
-	session << "SELECT count(*) FROM sys.dual", into(cntMem), now;
-	assert (0 == cntMem);
-
-	session << "INSERT INTO sys.dual VALUES ('test')", now;
-	session << "SELECT count(*) FROM sys.dual", into(cntMem), now;
-	assert (1 == cntMem);
-
-	// connect another session
-	Session session2(Poco::Data::SQLite::Connector::KEY, "dummy.db");
-	// verify it has it's own sys table
-	session2 << "SELECT count(*) FROM sys.dual", into(cntMem), now;
-	assert (0 == cntMem);
-	// verify it shares the file table
-	session2 << "SELECT count(*) FROM Test", into(cntFile), now;
-	assert (1 == cntFile);
-	session2 << "INSERT INTO sys.dual VALUES ('test')", now;
-	session2 << "SELECT count(*) FROM sys.dual", into(cntMem), now;
-	assert (1 == cntMem);
-
-	session << "DELETE FROM sys.dual", now;
-	session << "SELECT count(*) FROM sys.dual", into(cntMem), now;
-	assert (0 == cntMem);
-	session2 << "SELECT count(*) FROM sys.dual", into(cntMem), now;
-	assert (1 == cntMem);
-	session2 << "DELETE FROM sys.dual", now;
-	session2 << "SELECT count(*) FROM sys.dual", into(cntMem), now;
-	assert (0 == cntMem);
-
-	try
-	{
-		session << "DROP TABLE sys.dual", now;
-		fail ("must throw");
-	}
-	catch (InvalidAccessException&) { }
-
-}
-
-
 void SQLiteTest::testThreadModes()
 {
 	using namespace Poco::Data::SQLite;
@@ -2747,7 +2698,6 @@ CppUnit::Test* SQLiteTest::suite()
 	CppUnit_addTest(pSuite, SQLiteTest, testMultipleResults);
 	CppUnit_addTest(pSuite, SQLiteTest, testPair);
 	CppUnit_addTest(pSuite, SQLiteTest, testReconnect);
-	CppUnit_addTest(pSuite, SQLiteTest, testSystemTable);
 	CppUnit_addTest(pSuite, SQLiteTest, testThreadModes);
 
 	return pSuite;

Data/SQLite/testsuite/src/SQLiteTest.h

@@ -132,7 +132,6 @@ public:
 	void testMultipleResults();
 
 	void testReconnect();
-	void testSystemTable();
 
 	void testThreadModes();