diff --git a/src/Dibi/Connection.php b/src/Dibi/Connection.php
index 48718a0e..6eba0d8c 100644
--- a/src/Dibi/Connection.php
+++ b/src/Dibi/Connection.php
@@ -317,7 +317,7 @@ class Connection
 	{
 		$this->connected || $this->connect();
 		$rows = $this->driver->getAffectedRows();
-		if (!is_int($rows) || $rows < 0) {
+		if ($rows === NULL || $rows < 0) {
 			throw new Exception('Cannot retrieve number of affected rows.');
 		}
 		return $rows;
@@ -531,7 +531,7 @@ class Connection
 	/**
 	 * Executes SQL query and fetch result - shortcut for query() & fetch().
 	 * @param  mixed    one or more arguments
-	 * @return Row|FALSE
+	 * @return Row|NULL
 	 * @throws Exception
 	 */
 	public function fetch(...$args)
diff --git a/src/Dibi/DataSource.php b/src/Dibi/DataSource.php
index eb9d227f..e2ef9f5e 100644
--- a/src/Dibi/DataSource.php
+++ b/src/Dibi/DataSource.php
@@ -168,7 +168,7 @@ class DataSource implements IDataSource
 
 	/**
 	 * Generates, executes SQL query and fetches the single row.
-	 * @return Row|FALSE
+	 * @return Row|NULL
 	 */
 	public function fetch()
 	{
@@ -178,7 +178,7 @@ class DataSource implements IDataSource
 
 	/**
 	 * Like fetch(), but returns only first field.
-	 * @return mixed  value on success, FALSE if no next record
+	 * @return mixed  value on success, NULL if no next record
 	 */
 	public function fetchSingle()
 	{
diff --git a/src/Dibi/Drivers/FirebirdDriver.php b/src/Dibi/Drivers/FirebirdDriver.php
index e1ec7abb..ac2d7b7a 100644
--- a/src/Dibi/Drivers/FirebirdDriver.php
+++ b/src/Dibi/Drivers/FirebirdDriver.php
@@ -8,6 +8,7 @@
 namespace Dibi\Drivers;
 
 use Dibi;
+use Dibi\Helpers;
 
 
 /**
@@ -62,7 +63,7 @@ class FirebirdDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	 */
 	public function connect(array &$config)
 	{
-		Dibi\Helpers::alias($config, 'database', 'db');
+		Helpers::alias($config, 'database', 'db');
 
 		if (isset($config['resource'])) {
 			$this->connection = $config['resource'];
@@ -129,22 +130,22 @@ class FirebirdDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
-		return ibase_affected_rows($this->connection);
+		return Helpers::false2Null(ibase_affected_rows($this->connection));
 	}
 
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
 	 * @param  string     generator name
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
-		return ibase_gen_id($sequence, 0, $this->connection);
+		return Helpers::false2Null(ibase_gen_id($sequence, 0, $this->connection));
 	}
 
 
@@ -382,7 +383,7 @@ class FirebirdDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL  array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
@@ -398,7 +399,7 @@ class FirebirdDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 			}
 		}
 
-		return $result;
+		return Helpers::false2Null($result);
 	}
 
 
diff --git a/src/Dibi/Drivers/MsSqlDriver.php b/src/Dibi/Drivers/MsSqlDriver.php
index f6bcd4e6..627a0c69 100644
--- a/src/Dibi/Drivers/MsSqlDriver.php
+++ b/src/Dibi/Drivers/MsSqlDriver.php
@@ -104,17 +104,17 @@ class MsSqlDriver implements Dibi\Driver, Dibi\ResultDriver
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
-		return mssql_rows_affected($this->connection);
+		return Dibi\Helpers::false2Null(mssql_rows_affected($this->connection));
 	}
 
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
@@ -123,7 +123,7 @@ class MsSqlDriver implements Dibi\Driver, Dibi\ResultDriver
 			$row = mssql_fetch_row($res);
 			return $row[0];
 		}
-		return FALSE;
+		return NULL;
 	}
 
 
@@ -338,18 +338,18 @@ class MsSqlDriver implements Dibi\Driver, Dibi\ResultDriver
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL    array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
-		return mssql_fetch_array($this->resultSet, $assoc ? MSSQL_ASSOC : MSSQL_NUM);
+		return Dibi\Helpers::false2Null(mssql_fetch_array($this->resultSet, $assoc ? MSSQL_ASSOC : MSSQL_NUM));
 	}
 
 
 	/**
 	 * Moves cursor position without fetching row.
-	 * @param  int      the 0-based cursor pos to seek to
-	 * @return boolean  TRUE on success, FALSE if unable to seek to specified record
+	 * @param  int   the 0-based cursor pos to seek to
+	 * @return bool  TRUE on success, FALSE if unable to seek to specified record
 	 */
 	public function seek($row)
 	{
diff --git a/src/Dibi/Drivers/MsSqlReflector.php b/src/Dibi/Drivers/MsSqlReflector.php
index 52cc9fd4..84d3c1ac 100644
--- a/src/Dibi/Drivers/MsSqlReflector.php
+++ b/src/Dibi/Drivers/MsSqlReflector.php
@@ -57,7 +57,7 @@ class MsSqlReflector implements Dibi\Reflector
 	public function getTableCount($table, $fallback = TRUE)
 	{
 		if (empty($table)) {
-			return FALSE;
+			return NULL;
 		}
 		$result = $this->driver->query("
 			SELECT MAX(rowcnt)
@@ -71,7 +71,7 @@ class MsSqlReflector implements Dibi\Reflector
 				$row = $this->driver->query("SELECT COUNT(*) FROM {$this->driver->escapeIdentifier($table)}")->fetch(FALSE);
 				$count = intval($row[0]);
 			} else {
-				$count = FALSE;
+				$count = NULL;
 			}
 		} else {
 			$count = intval($row[0]);
diff --git a/src/Dibi/Drivers/MySqliDriver.php b/src/Dibi/Drivers/MySqliDriver.php
index 72af7c8e..39dd417a 100644
--- a/src/Dibi/Drivers/MySqliDriver.php
+++ b/src/Dibi/Drivers/MySqliDriver.php
@@ -203,17 +203,17 @@ class MySqliDriver implements Dibi\Driver, Dibi\ResultDriver
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
-		return mysqli_affected_rows($this->connection) === -1 ? FALSE : mysqli_affected_rows($this->connection);
+		return mysqli_affected_rows($this->connection) === -1 ? NULL : mysqli_affected_rows($this->connection);
 	}
 
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
@@ -432,7 +432,7 @@ class MySqliDriver implements Dibi\Driver, Dibi\ResultDriver
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL    array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
diff --git a/src/Dibi/Drivers/OdbcDriver.php b/src/Dibi/Drivers/OdbcDriver.php
index 10cbcc66..f08294ea 100644
--- a/src/Dibi/Drivers/OdbcDriver.php
+++ b/src/Dibi/Drivers/OdbcDriver.php
@@ -34,8 +34,8 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	/** @var bool */
 	private $autoFree = TRUE;
 
-	/** @var int|FALSE  Affected rows */
-	private $affectedRows = FALSE;
+	/** @var int|NULL  Affected rows */
+	private $affectedRows;
 
 	/** @var int  Cursor */
 	private $row = 0;
@@ -100,14 +100,14 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	 */
 	public function query($sql)
 	{
-		$this->affectedRows = FALSE;
+		$this->affectedRows = NULL;
 		$res = @odbc_exec($this->connection, $sql); // intentionally @
 
 		if ($res === FALSE) {
 			throw new Dibi\DriverException(odbc_errormsg($this->connection) . ' ' . odbc_error($this->connection), 0, $sql);
 
 		} elseif (is_resource($res)) {
-			$this->affectedRows = odbc_num_rows($res);
+			$this->affectedRows = Dibi\Helpers::false2Null(odbc_num_rows($res));
 			return $this->createResultDriver($res);
 		}
 		return NULL;
@@ -116,7 +116,7 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
@@ -126,7 +126,7 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
@@ -363,16 +363,16 @@ class OdbcDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL    array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
 		if ($assoc) {
-			return odbc_fetch_array($this->resultSet, ++$this->row);
+			return Dibi\Helpers::false2Null(odbc_fetch_array($this->resultSet, ++$this->row));
 		} else {
 			$set = $this->resultSet;
 			if (!odbc_fetch_row($set, ++$this->row)) {
-				return FALSE;
+				return NULL;
 			}
 			$count = odbc_num_fields($set);
 			$cols = [];
diff --git a/src/Dibi/Drivers/OracleDriver.php b/src/Dibi/Drivers/OracleDriver.php
index 319cb327..3c489c15 100644
--- a/src/Dibi/Drivers/OracleDriver.php
+++ b/src/Dibi/Drivers/OracleDriver.php
@@ -43,8 +43,8 @@ class OracleDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	/** @var string  Date and datetime format */
 	private $fmtDate, $fmtDateTime;
 
-	/** @var int|FALSE Number of affected rows */
-	private $affectedRows = FALSE;
+	/** @var int|NULL Number of affected rows */
+	private $affectedRows;
 
 
 	/**
@@ -109,7 +109,7 @@ class OracleDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	 */
 	public function query($sql)
 	{
-		$this->affectedRows = FALSE;
+		$this->affectedRows = NULL;
 		$res = oci_parse($this->connection, $sql);
 		if ($res) {
 			@oci_execute($res, $this->autocommit ? OCI_COMMIT_ON_SUCCESS : OCI_DEFAULT);
@@ -118,7 +118,7 @@ class OracleDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 				throw self::createException($err['message'], $err['code'], $sql);
 
 			} elseif (is_resource($res)) {
-				$this->affectedRows = oci_num_rows($res);
+				$this->affectedRows = Dibi\Helpers::false2Null(oci_num_rows($res));
 				return $this->createResultDriver($res);
 			}
 		} else {
@@ -151,7 +151,7 @@ class OracleDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
@@ -161,12 +161,12 @@ class OracleDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
 		$row = $this->query("SELECT $sequence.CURRVAL AS ID FROM DUAL")->fetch(TRUE);
-		return isset($row['ID']) ? (int) $row['ID'] : FALSE;
+		return isset($row['ID']) ? (int) $row['ID'] : NULL;
 	}
 
 
@@ -396,11 +396,11 @@ class OracleDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL    array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
-		return oci_fetch_array($this->resultSet, ($assoc ? OCI_ASSOC : OCI_NUM) | OCI_RETURN_NULLS);
+		return Dibi\Helpers::false2Null(oci_fetch_array($this->resultSet, ($assoc ? OCI_ASSOC : OCI_NUM) | OCI_RETURN_NULLS));
 	}
 
 
diff --git a/src/Dibi/Drivers/PdoDriver.php b/src/Dibi/Drivers/PdoDriver.php
index 5ebb130a..9c719bd4 100644
--- a/src/Dibi/Drivers/PdoDriver.php
+++ b/src/Dibi/Drivers/PdoDriver.php
@@ -8,6 +8,7 @@
 namespace Dibi\Drivers;
 
 use Dibi;
+use Dibi\Helpers;
 use PDO;
 
 
@@ -33,8 +34,8 @@ class PdoDriver implements Dibi\Driver, Dibi\ResultDriver
 	/** @var \PDOStatement|NULL  Resultset resource */
 	private $resultSet;
 
-	/** @var int|FALSE  Affected rows */
-	private $affectedRows = FALSE;
+	/** @var int|NULL  Affected rows */
+	private $affectedRows;
 
 	/** @var string */
 	private $driverName;
@@ -63,7 +64,7 @@ class PdoDriver implements Dibi\Driver, Dibi\ResultDriver
 	{
 		$foo = &$config['dsn'];
 		$foo = &$config['options'];
-		Dibi\Helpers::alias($config, 'resource', 'pdo');
+		Helpers::alias($config, 'resource', 'pdo');
 
 		if ($config['resource'] instanceof PDO) {
 			$this->connection = $config['resource'];
@@ -106,11 +107,11 @@ class PdoDriver implements Dibi\Driver, Dibi\ResultDriver
 		// must detect if SQL returns result set or num of affected rows
 		$cmd = strtoupper(substr(ltrim($sql), 0, 6));
 		static $list = ['UPDATE' => 1, 'DELETE' => 1, 'INSERT' => 1, 'REPLAC' => 1];
-		$this->affectedRows = FALSE;
+		$this->affectedRows = NULL;
 
 		if (isset($list[$cmd])) {
-			$this->affectedRows = $this->connection->exec($sql);
-			if ($this->affectedRows !== FALSE) {
+			$this->affectedRows = Helpers::false2Null($this->connection->exec($sql));
+			if ($this->affectedRows !== NULL) {
 				return NULL;
 			}
 		} else {
@@ -143,7 +144,7 @@ class PdoDriver implements Dibi\Driver, Dibi\ResultDriver
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
@@ -153,11 +154,11 @@ class PdoDriver implements Dibi\Driver, Dibi\ResultDriver
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
-		return $this->connection->lastInsertId();
+		return Helpers::false2Null($this->connection->lastInsertId());
 	}
 
 
@@ -499,11 +500,11 @@ class PdoDriver implements Dibi\Driver, Dibi\ResultDriver
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL    array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
-		return $this->resultSet->fetch($assoc ? PDO::FETCH_ASSOC : PDO::FETCH_NUM);
+		return Helpers::false2Null($this->resultSet->fetch($assoc ? PDO::FETCH_ASSOC : PDO::FETCH_NUM));
 	}
 
 
diff --git a/src/Dibi/Drivers/PostgreDriver.php b/src/Dibi/Drivers/PostgreDriver.php
index a07e866c..6e7bafd1 100644
--- a/src/Dibi/Drivers/PostgreDriver.php
+++ b/src/Dibi/Drivers/PostgreDriver.php
@@ -8,6 +8,7 @@
 namespace Dibi\Drivers;
 
 use Dibi;
+use Dibi\Helpers;
 
 
 /**
@@ -35,8 +36,8 @@ class PostgreDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	/** @var bool */
 	private $autoFree = TRUE;
 
-	/** @var int|FALSE  Affected rows */
-	private $affectedRows = FALSE;
+	/** @var int|NULL  Affected rows */
+	private $affectedRows;
 
 
 	/**
@@ -69,8 +70,8 @@ class PostgreDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 				$string = $config['string'];
 			} else {
 				$string = '';
-				Dibi\Helpers::alias($config, 'user', 'username');
-				Dibi\Helpers::alias($config, 'dbname', 'database');
+				Helpers::alias($config, 'user', 'username');
+				Helpers::alias($config, 'dbname', 'database');
 				foreach (['host', 'hostaddr', 'port', 'dbname', 'user', 'password', 'connect_timeout', 'options', 'sslmode', 'service'] as $key) {
 					if (isset($config[$key])) {
 						$string .= $key . '=' . $config[$key] . ' ';
@@ -133,14 +134,14 @@ class PostgreDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	 */
 	public function query($sql)
 	{
-		$this->affectedRows = FALSE;
+		$this->affectedRows = NULL;
 		$res = @pg_query($this->connection, $sql); // intentionally @
 
 		if ($res === FALSE) {
 			throw self::createException(pg_last_error($this->connection), NULL, $sql);
 
 		} elseif (is_resource($res)) {
-			$this->affectedRows = pg_affected_rows($res);
+			$this->affectedRows = Helpers::false2Null(pg_affected_rows($res));
 			if (pg_num_fields($res)) {
 				return $this->createResultDriver($res);
 			}
@@ -179,7 +180,7 @@ class PostgreDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
@@ -189,7 +190,7 @@ class PostgreDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
@@ -201,11 +202,11 @@ class PostgreDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 		}
 
 		if (!$res) {
-			return FALSE;
+			return NULL;
 		}
 
 		$row = $res->fetch(FALSE);
-		return is_array($row) ? $row[0] : FALSE;
+		return is_array($row) ? $row[0] : NULL;
 	}
 
 
@@ -438,11 +439,11 @@ class PostgreDriver implements Dibi\Driver, Dibi\ResultDriver, Dibi\Reflector
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL    array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
-		return pg_fetch_array($this->resultSet, NULL, $assoc ? PGSQL_ASSOC : PGSQL_NUM);
+		return Helpers::false2Null(pg_fetch_array($this->resultSet, NULL, $assoc ? PGSQL_ASSOC : PGSQL_NUM));
 	}
 
 
diff --git a/src/Dibi/Drivers/Sqlite3Driver.php b/src/Dibi/Drivers/Sqlite3Driver.php
index 083fc99b..3ecff9ba 100644
--- a/src/Dibi/Drivers/Sqlite3Driver.php
+++ b/src/Dibi/Drivers/Sqlite3Driver.php
@@ -154,7 +154,7 @@ class Sqlite3Driver implements Dibi\Driver, Dibi\ResultDriver
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
@@ -164,7 +164,7 @@ class Sqlite3Driver implements Dibi\Driver, Dibi\ResultDriver
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
@@ -381,11 +381,14 @@ class Sqlite3Driver implements Dibi\Driver, Dibi\ResultDriver
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL    array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
 		$row = $this->resultSet->fetchArray($assoc ? SQLITE3_ASSOC : SQLITE3_NUM);
+		if (!$row) {
+			return NULL;
+		}
 		$charset = $this->charset === NULL ? NULL : $this->charset . '//TRANSLIT';
 		if ($row && ($assoc || $charset)) {
 			$tmp = [];
diff --git a/src/Dibi/Drivers/SqlsrvDriver.php b/src/Dibi/Drivers/SqlsrvDriver.php
index 96847d99..2fa74bd8 100644
--- a/src/Dibi/Drivers/SqlsrvDriver.php
+++ b/src/Dibi/Drivers/SqlsrvDriver.php
@@ -38,8 +38,8 @@ class SqlsrvDriver implements Dibi\Driver, Dibi\ResultDriver
 	/** @var bool */
 	private $autoFree = TRUE;
 
-	/** @var int|FALSE  Affected rows */
-	private $affectedRows = FALSE;
+	/** @var int|NULL  Affected rows */
+	private $affectedRows;
 
 	/** @var string */
 	private $version = '';
@@ -109,7 +109,7 @@ class SqlsrvDriver implements Dibi\Driver, Dibi\ResultDriver
 	 */
 	public function query($sql)
 	{
-		$this->affectedRows = FALSE;
+		$this->affectedRows = NULL;
 		$res = sqlsrv_query($this->connection, $sql);
 
 		if ($res === FALSE) {
@@ -117,7 +117,7 @@ class SqlsrvDriver implements Dibi\Driver, Dibi\ResultDriver
 			throw new Dibi\DriverException($info[0]['message'], $info[0]['code'], $sql);
 
 		} elseif (is_resource($res)) {
-			$this->affectedRows = sqlsrv_rows_affected($res);
+			$this->affectedRows = Helpers::false2Null(sqlsrv_rows_affected($res));
 			return $this->createResultDriver($res);
 		}
 		return NULL;
@@ -126,7 +126,7 @@ class SqlsrvDriver implements Dibi\Driver, Dibi\ResultDriver
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	public function getAffectedRows()
 	{
@@ -136,7 +136,7 @@ class SqlsrvDriver implements Dibi\Driver, Dibi\ResultDriver
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	public function getInsertId($sequence)
 	{
@@ -145,7 +145,7 @@ class SqlsrvDriver implements Dibi\Driver, Dibi\ResultDriver
 			$row = sqlsrv_fetch_array($res, SQLSRV_FETCH_NUMERIC);
 			return $row[0];
 		}
-		return FALSE;
+		return NULL;
 	}
 
 
@@ -369,7 +369,7 @@ class SqlsrvDriver implements Dibi\Driver, Dibi\ResultDriver
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
 	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @return array|NULL    array on success, NULL if no next record
 	 */
 	public function fetch($assoc)
 	{
diff --git a/src/Dibi/Fluent.php b/src/Dibi/Fluent.php
index ad4fcd93..0974dff3 100644
--- a/src/Dibi/Fluent.php
+++ b/src/Dibi/Fluent.php
@@ -319,7 +319,7 @@ class Fluent implements IDataSource
 
 	/**
 	 * Generates, executes SQL query and fetches the single row.
-	 * @return Row|FALSE
+	 * @return Row|NULL
 	 */
 	public function fetch()
 	{
@@ -333,7 +333,7 @@ class Fluent implements IDataSource
 
 	/**
 	 * Like fetch(), but returns only first field.
-	 * @return mixed  value on success, FALSE if no next record
+	 * @return mixed  value on success, NULL if no next record
 	 */
 	public function fetchSingle()
 	{
diff --git a/src/Dibi/Helpers.php b/src/Dibi/Helpers.php
index caa10274..59db2ace 100644
--- a/src/Dibi/Helpers.php
+++ b/src/Dibi/Helpers.php
@@ -282,4 +282,13 @@ class Helpers
 		return $count;
 	}
 
+
+	/**
+	 * @internal
+	 */
+	public static function false2Null($val)
+	{
+		return $val === FALSE ? NULL : $val;
+	}
+
 }
diff --git a/src/Dibi/Result.php b/src/Dibi/Result.php
index 48606938..f954a622 100644
--- a/src/Dibi/Result.php
+++ b/src/Dibi/Result.php
@@ -174,20 +174,20 @@ class Result implements IDataSource
 	/**
 	 * Fetches the row at current position, process optional type conversion.
 	 * and moves the internal cursor to the next position
-	 * @return Row|FALSE
+	 * @return Row|NULL
 	 */
 	final public function fetch()
 	{
 		$row = $this->getResultDriver()->fetch(TRUE);
-		if (!is_array($row)) {
-			return FALSE;
+		if ($row === NULL) {
+			return NULL;
 		}
 		$this->fetched = TRUE;
 		$this->normalize($row);
 		if ($this->rowFactory) {
 			return ($this->rowFactory)($row);
 		} elseif ($this->rowClass) {
-			$row = new $this->rowClass($row);
+			return new $this->rowClass($row);
 		}
 		return $row;
 	}
@@ -195,13 +195,13 @@ class Result implements IDataSource
 
 	/**
 	 * Like fetch(), but returns only first field.
-	 * @return mixed value on success, FALSE if no next record
+	 * @return mixed value on success, NULL if no next record
 	 */
 	final public function fetchSingle()
 	{
 		$row = $this->getResultDriver()->fetch(TRUE);
-		if (!is_array($row)) {
-			return FALSE;
+		if ($row === NULL) {
+			return NULL;
 		}
 		$this->fetched = TRUE;
 		$this->normalize($row);
diff --git a/src/Dibi/dibi.php b/src/Dibi/dibi.php
index 82d16094..d5615b33 100644
--- a/src/Dibi/dibi.php
+++ b/src/Dibi/dibi.php
@@ -182,7 +182,7 @@ class dibi
 	/**
 	 * Executes SQL query and fetch result - Monostate for Dibi\Connection::query() & fetch().
 	 * @param  mixed    one or more arguments
-	 * @return Dibi\Row
+	 * @return Dibi\Row|NULL
 	 * @throws Dibi\Exception
 	 */
 	public static function fetch(...$args)
diff --git a/src/Dibi/interfaces.php b/src/Dibi/interfaces.php
index 99318027..9119ebbd 100644
--- a/src/Dibi/interfaces.php
+++ b/src/Dibi/interfaces.php
@@ -49,13 +49,13 @@ interface Driver
 
 	/**
 	 * Gets the number of affected rows by the last INSERT, UPDATE or DELETE query.
-	 * @return int|FALSE  number of rows or FALSE on error
+	 * @return int|NULL  number of rows or NULL on error
 	 */
 	function getAffectedRows();
 
 	/**
 	 * Retrieves the ID generated for an AUTO_INCREMENT column by the previous INSERT query.
-	 * @return int|FALSE  int on success or FALSE on failure
+	 * @return int|NULL  int on success or NULL on failure
 	 */
 	function getInsertId($sequence);
 
@@ -166,16 +166,16 @@ interface ResultDriver
 
 	/**
 	 * Moves cursor position without fetching row.
-	 * @param  int      the 0-based cursor pos to seek to
-	 * @return boolean  TRUE on success, FALSE if unable to seek to specified record
+	 * @param  int   the 0-based cursor pos to seek to
+	 * @return bool  TRUE on success, FALSE if unable to seek to specified record
 	 * @throws Exception
 	 */
 	function seek($row);
 
 	/**
 	 * Fetches the row at current position and moves the internal cursor to the next position.
-	 * @param  bool     TRUE for associative array, FALSE for numeric
-	 * @return array    array on success, nonarray if no next record
+	 * @param  bool          TRUE for associative array, FALSE for numeric
+	 * @return array|NULL    array on success, NULL if no next record
 	 * @internal
 	 */
 	function fetch($type);
diff --git a/tests/dibi/Fluent.fetch.limit.mssql.phpt b/tests/dibi/Fluent.fetch.limit.mssql.phpt
index 0adfff44..f75d6a81 100644
--- a/tests/dibi/Fluent.fetch.limit.mssql.phpt
+++ b/tests/dibi/Fluent.fetch.limit.mssql.phpt
@@ -25,7 +25,7 @@ class MockDriver extends Dibi\Drivers\SqlsrvDriver
 
 	function fetch($assoc)
 	{
-		return FALSE;
+		return NULL;
 	}
 }