diff --git a/framework/db/Command.php b/framework/db/Command.php
index d7817bf..7c83839 100644
--- a/framework/db/Command.php
+++ b/framework/db/Command.php
@@ -144,7 +144,7 @@ class Command extends \yii\base\Component
 	{
 		$this->prepare();
 		if ($dataType === null) {
-			$this->pdoStatement->bindParam($name, $value, $this->connection->getPdoType(gettype($value)));
+			$this->pdoStatement->bindParam($name, $value, $this->getPdoType(gettype($value)));
 		} elseif ($length === null) {
 			$this->pdoStatement->bindParam($name, $value, $dataType);
 		} elseif ($driverOptions === null) {
@@ -171,7 +171,7 @@ class Command extends \yii\base\Component
 	{
 		$this->prepare();
 		if ($dataType === null) {
-			$this->pdoStatement->bindValue($name, $value, $this->connection->getPdoType(gettype($value)));
+			$this->pdoStatement->bindValue($name, $value, $this->getPdoType(gettype($value)));
 		} else {
 			$this->pdoStatement->bindValue($name, $value, $dataType);
 		}
@@ -199,7 +199,7 @@ class Command extends \yii\base\Component
 					$type = $value[1];
 					$value = $value[0];
 				} else {
-					$type = $this->connection->getPdoType(gettype($value));
+					$type = $this->getPdoType(gettype($value));
 				}
 				$this->pdoStatement->bindValue($name, $value, $type);
 				$this->_params[$name] = $value;
@@ -209,6 +209,23 @@ class Command extends \yii\base\Component
 	}
 
 	/**
+	 * Determines the PDO type for the give PHP data type.
+	 * @param string $type The PHP type (obtained by `gettype()` call).
+	 * @return integer the corresponding PDO type
+	 * @see http://www.php.net/manual/en/pdo.constants.php
+	 */
+	private function getPdoType($type)
+	{
+		static $typeMap = array(
+			'boolean' => \PDO::PARAM_BOOL,
+			'integer' => \PDO::PARAM_INT,
+			'string' => \PDO::PARAM_STR,
+			'NULL' => \PDO::PARAM_NULL,
+		);
+		return isset($typeMap[$type]) ? $typeMap[$type] : \PDO::PARAM_STR;
+	}
+
+	/**
 	 * Executes the SQL statement.
 	 * This method should only be used for executing non-query SQL statement, such as `INSERT`, `DELETE`, `UPDATE` SQLs.
 	 * No result set will be returned.
diff --git a/framework/db/Connection.php b/framework/db/Connection.php
index 0136437..0b04b2a 100644
--- a/framework/db/Connection.php
+++ b/framework/db/Connection.php
@@ -550,23 +550,6 @@ class Connection extends \yii\base\ApplicationComponent
 	}
 
 	/**
-	 * Determines the PDO type for the give PHP data type.
-	 * @param string $type The PHP type (obtained by `gettype()` call).
-	 * @return integer the corresponding PDO type
-	 * @see http://www.php.net/manual/en/pdo.constants.php
-	 */
-	public function getPdoType($type)
-	{
-		static $typeMap = array(
-			'boolean' => \PDO::PARAM_BOOL,
-			'integer' => \PDO::PARAM_INT,
-			'string' => \PDO::PARAM_STR,
-			'NULL' => \PDO::PARAM_NULL,
-		);
-		return isset($typeMap[$type]) ? $typeMap[$type] : \PDO::PARAM_STR;
-	}
-
-	/**
 	 * Returns the name of the DB driver for the current [[dsn]].
 	 * @return string name of the DB driver
 	 */
diff --git a/tests/unit/framework/db/ConnectionTest.php b/tests/unit/framework/db/ConnectionTest.php
index e035eb2..907dda6 100644
--- a/tests/unit/framework/db/ConnectionTest.php
+++ b/tests/unit/framework/db/ConnectionTest.php
@@ -76,15 +76,6 @@ class ConnectionTest extends \yiiunit\MysqlTestCase
 		$this->assertEquals('(column)', $connection->quoteColumnName('(column)'));
 	}
 
-	function testGetPdoType()
-	{
-		$connection = $this->getConnection(false);
-		$this->assertEquals(\PDO::PARAM_BOOL, $connection->getPdoType('boolean'));
-		$this->assertEquals(\PDO::PARAM_INT, $connection->getPdoType('integer'));
-		$this->assertEquals(\PDO::PARAM_STR, $connection->getPdoType('string'));
-		$this->assertEquals(\PDO::PARAM_NULL, $connection->getPdoType('NULL'));
-	}
-
 	function testAttribute()
 	{