diff --git a/framework/base/Model.php b/framework/base/Model.php
index a75b694..040e229 100644
--- a/framework/base/Model.php
+++ b/framework/base/Model.php
@@ -102,11 +102,11 @@ class Model extends Component implements Initable, \IteratorAggregate, \ArrayAcc
 			return self::$_attributes[$className];
 		}
 
-		$class = new ReflectionClass($this);
+		$class = new \ReflectionClass($this);
 		$names = array();
-		foreach ($class->getProperties() as $property) {
+		foreach ($class->getProperties(\ReflectionProperty::IS_PUBLIC) as $property) {
 			$name = $property->getName();
-			if ($property->isPublic() && !$property->isStatic()) {
+			if (!$property->isStatic()) {
 				$names[] = $name;
 			}
 		}
diff --git a/framework/db/dao/Command.php b/framework/db/dao/Command.php
index 5df6965..688b14e 100644
--- a/framework/db/dao/Command.php
+++ b/framework/db/dao/Command.php
@@ -94,8 +94,8 @@ class Command extends \yii\base\Component
 		}
 		else {
 			$this->query = new Query;
-			if (is_array($this->query)) {
-				$this->query->fromArray($this->query);
+			if (is_array($query)) {
+				$this->query->fromArray($query);
 			}
 			else {
 				$this->_sql = $query;
@@ -124,9 +124,9 @@ class Command extends \yii\base\Component
 	/**
 	 * @return string the SQL statement to be executed
 	 */
-	public function getSql()
+	public function getSql($rebuild = false)
 	{
-		if ($this->_sql == '' && is_object($this->query)) {
+		if ($this->_sql === null || $rebuild) {
 			$this->_sql = $this->query->getSql($this->connection);
 		}
 		return $this->_sql;
@@ -168,7 +168,7 @@ class Command extends \yii\base\Component
 				\Yii::log('Error in preparing SQL: ' . $this->getSql(), CLogger::LEVEL_ERROR, 'system.db.Command');
                 $errorInfo = $e instanceof \PDOException ? $e->errorInfo : null;
 				throw new Exception('Unable to prepare the SQL statement: {error}',
-					array('{error}' => $e->getMessage())), (int)$e->getCode(), $errorInfo);
+					array('{error}' => $e->getMessage()), (int)$e->getCode(), $errorInfo);
 			}
 		}
 	}
diff --git a/framework/db/dao/Query.php b/framework/db/dao/Query.php
index cf96ad1..08fc11d 100644
--- a/framework/db/dao/Query.php
+++ b/framework/db/dao/Query.php
@@ -94,6 +94,136 @@ class Query extends \yii\base\Component
 		}
 	}
 
+	public function mergeWith($query, $useAnd = true)
+	{
+		$and = $useAnd ? 'AND' : 'OR';
+		if (is_array($query)) {
+			$query = new self($query);
+		}
+
+		if ($this->select !== $query->select) {
+			if($this->select === '*') {
+				$this->select = $query->select;
+			}
+			elseif($query->select!=='*') {
+				$select1 = is_string($this->select) ? preg_split('/\s*,\s*/', trim($this->select), -1, PREG_SPLIT_NO_EMPTY) : $this->select;
+				$select2 = is_string($query->select) ? preg_split('/\s*,\s*/', trim($query->select), -1, PREG_SPLIT_NO_EMPTY) : $query->select;
+				$this->select = array_merge($select1, array_diff($select2, $select1));
+			}
+		}
+
+		if ($this->selectOption !== $query->selectOption) {
+			if ($this->selectOption === null) {
+				$this->selectOption = $query->selectOption;
+			}
+			elseif ($query->selectOption !== null) {
+				$this->selectOption .= ' ' . $query->selectOption;
+			}
+		}
+
+		if ($query->distinct) {
+			$this->distinct = $query->distinct;
+		}
+
+		if ($this->where !== $query->where) {
+			if (empty($this->where)) {
+				$this->where = $query->where;
+			}
+			elseif (!empty($query->where)) {
+				$this->where = array('AND', $this->where, $query->where);
+			}
+		}
+
+		if ($this->params !== $query->params) {
+			$this->params = $this->addParams($query->params);
+		}
+
+		if ($query->limit !== null) {
+			$this->limit = $query->limit;
+		}
+
+		if ($query->offset !== null) {
+			$this->offset = $query->offset;
+		}
+
+		if ($this->orderBy !== $query->orderBy) {
+			if (empty($this->orderBy)) {
+				$this->orderBy = $query->orderBy;
+			}
+			elseif (!empty($query->orderBy)) {
+				if (!is_array($this->orderBy)) {
+					$this->orderBy = array($this->orderBy);
+				}
+				if (is_array($query->orderBy)) {
+					$this->orderBy = array_merge($this->orderBy, $query->orderBy);
+				}
+				else {
+					$this->orderBy[] = $query->orderBy;
+				}
+			}
+		}
+
+		if ($this->groupBy !== $query->groupBy) {
+			if (empty($this->groupBy)) {
+				$this->groupBy = $query->groupBy;
+			}
+			elseif (!empty($query->groupBy)) {
+				if (!is_array($this->groupBy)) {
+					$this->groupBy = array($this->groupBy);
+				}
+				if (is_array($query->groupBy)) {
+					$this->groupBy = array_merge($this->groupBy, $query->groupBy);
+				}
+				else {
+					$this->groupBy[] = $query->groupBy;
+				}
+			}
+		}
+
+		if ($this->join !== $query->join) {
+			if (empty($this->join)) {
+				$this->join = $query->join;
+			}
+			elseif (!empty($query->join)) {
+				if (!is_array($this->join)) {
+					$this->join = array($this->join);
+				}
+				if (is_array($query->join)) {
+					$this->join = array_merge($this->join, $query->join);
+				}
+				else {
+					$this->join[] = $query->join;
+				}
+			}
+		}
+
+		if ($this->having !== $query->having) {
+			if (empty($this->having)) {
+				$this->having = $query->having;
+			}
+			elseif (!empty($query->having)) {
+				$this->having = array('AND', $this->having, $query->having);
+			}
+		}
+
+		if ($this->union !== $query->union) {
+			if (empty($this->union)) {
+				$this->union = $query->union;
+			}
+			elseif (!empty($query->union)) {
+				if (!is_array($this->union)) {
+					$this->union = array($this->union);
+				}
+				if (is_array($query->union)) {
+					$this->union = array_merge($this->union, $query->union);
+				}
+				else {
+					$this->union[] = $query->union;
+				}
+			}
+		}
+	}
+
 	/**
 	 * Appends a condition to the existing {@link condition}.
 	 * The new condition and the existing condition will be concatenated via the specified operator
@@ -372,15 +502,44 @@ class Query extends \yii\base\Component
 		return $this;
 	}
 
+	public function reset()
+	{
+		$this->select = null;
+		$this->selectOption = null;
+		$this->from = null;
+		$this->distinct = null;
+		$this->where = null;
+		$this->limit = null;
+		$this->offset = null;
+		$this->orderBy = null;
+		$this->groupBy = null;
+		$this->join = null;
+		$this->having = null;
+		$this->params = array();
+		$this->union = null;
+	}
+
+	public function fromArray($array)
+	{
+		$this->reset();
+		foreach (array('select', 'selectOption', 'from', 'distinct', 'where', 'limit', 'offset', 'orderBy', 'groupBy', 'join', 'having', 'params', 'union') as $name) {
+			if (isset($array[$name])) {
+				$this->$name = $array[$name];
+			}
+		}
+	}
+
 	/**
 	 * @return array the array representation of the criteria
-	 * @since 1.0.6
 	 */
 	public function toArray()
 	{
 		$result = array();
-		foreach (array('select', 'condition', 'params', 'limit', 'offset', 'order', 'group', 'join', 'having', 'distinct', 'scopes', 'with', 'alias', 'index', 'together') as $name)
-			$result[$name] = $this->$name;
+		foreach (array('select', 'selectOption', 'from', 'distinct', 'where', 'limit', 'offset', 'orderBy', 'groupBy', 'join', 'having', 'params', 'union') as $name) {
+			if (!empty($this->$name)) {
+				$result[$name] = $this->$name;
+			}
+		}
 		return $result;
 	}
 }
diff --git a/tests/unit/data/config.php b/tests/unit/data/config.php
index 865edc6..2473c85 100644
--- a/tests/unit/data/config.php
+++ b/tests/unit/data/config.php
@@ -5,5 +5,6 @@ return array(
 		'dsn' => 'mysql:host=127.0.0.1;dbname=yiitest',
 		'username' => 'root',
 		'password' => '',
+		'fixture' => __DIR__ . '/mysql.sql',
 	),
 );
\ No newline at end of file
diff --git a/tests/unit/data/mysql.sql b/tests/unit/data/mysql.sql
index 057b1ad..c2af862 100644
--- a/tests/unit/data/mysql.sql
+++ b/tests/unit/data/mysql.sql
@@ -4,6 +4,16 @@
  * and create an account 'test/test' which owns this test database.
  */
 
+DROP TABLE IF EXISTS types CASCADE;
+DROP TABLE IF EXISTS items CASCADE;
+DROP TABLE IF EXISTS orders CASCADE;
+DROP TABLE IF EXISTS post_category CASCADE;
+DROP TABLE IF EXISTS categories CASCADE;
+DROP TABLE IF EXISTS comments CASCADE;
+DROP TABLE IF EXISTS posts CASCADE;
+DROP TABLE IF EXISTS profiles CASCADE;
+DROP TABLE IF EXISTS users CASCADE;
+
 CREATE TABLE users
 (
 	id INTEGER NOT NULL PRIMARY KEY AUTO_INCREMENT,
diff --git a/tests/unit/framework/db/dao/CommandTest.php b/tests/unit/framework/db/dao/CommandTest.php
new file mode 100644
index 0000000..9754ae3
--- /dev/null
+++ b/tests/unit/framework/db/dao/CommandTest.php
@@ -0,0 +1,296 @@
+<?php
+
+use yii\db\dao\Connection;
+use yii\db\dao\Command;
+use yii\db\dao\Query;
+
+class CommandTest extends TestCase
+{
+	private $connection;
+
+	function setUp()
+	{
+		if(!extension_loaded('pdo') || !extension_loaded('pdo_mysql'))
+			$this->markTestSkipped('pdo and pdo_mysql extensions are required.');
+
+		$params = $this->getParam('mysql');
+		$this->connection = new Connection($params['dsn'], $params['username'], $params['password']);
+		$this->connection->open();
+		$this->connection->pdo->exec(file_get_contents($params['fixture']));
+	}
+
+	function tearDown()
+	{
+		$this->connection->close();
+	}
+
+	function testConstruct()
+	{
+		$command = $this->connection->createCommand();
+		$this->assertEquals("SELECT *\nFROM ", $command->sql);
+
+		$sql='SELECT * FROM posts';
+		$command = $this->connection->createCommand($sql);
+		$this->assertEquals($sql, $command->sql);
+
+		$query = new Query;
+		$command = $this->connection->createCommand($query);
+		$this->assertEquals($query, $command->query);
+
+		$query = array('select'=>'id', 'from'=>'posts');
+		$command = $this->connection->createCommand($query);
+		$this->assertEquals($query, $command->query->toArray());
+	}
+
+	function testReset()
+	{
+
+	}
+
+	function testGetSetSql()
+	{
+
+	}
+
+	function testPrepare()
+	{
+
+	}
+
+	function testBindParam()
+	{
+
+	}
+
+	function testBindValue()
+	{
+
+	}
+
+	function testExecute()
+	{
+
+	}
+
+	function testQuery()
+	{
+
+	}
+
+	function testQueryRow()
+	{
+
+	}
+
+	function testQueryAll()
+	{
+
+	}
+
+	function testQueryColumn()
+	{
+
+	}
+
+	function testQueryScalar()
+	{
+
+	}
+
+	function testFetchMode()
+	{
+
+	}
+
+s	/*
+	function testPrepare()
+	{
+		$sql='SELECT title FROM posts';
+		$command=$this->connection->createCommand($sql);
+		$this->assertEquals($command->pdoStatement,null);
+		$command->prepare();
+		$this->assertTrue($command->pdoStatement instanceof PDOStatement);
+		$this->assertEquals($command->queryScalar(),'post 1');
+
+		$command->text='Bad SQL';
+		$this->setExpectedException('CException');
+		$command->prepare();
+	}
+
+	function testCancel()
+	{
+		$sql='SELECT title FROM posts';
+		$command=$this->connection->createCommand($sql);
+		$command->prepare();
+		$this->assertTrue($command->pdoStatement instanceof PDOStatement);
+		$command->cancel();
+		$this->assertEquals($command->pdoStatement,null);
+	}
+
+	function testExecute()
+	{
+		$sql='INSERT INTO comments(content,post_id,author_id) VALUES (\'test comment\', 1, 1)';
+		$command=$this->connection->createCommand($sql);
+		$this->assertEquals($command->execute(),1);
+		$this->assertEquals($command->execute(),1);
+		$command=$this->connection->createCommand('SELECT * FROM comments WHERE content=\'test comment\'');
+		$this->assertEquals($command->execute(),0);
+		$command=$this->connection->createCommand('SELECT COUNT(*) FROM comments WHERE content=\'test comment\'');
+		$this->assertEquals($command->queryScalar(),2);
+
+		$command=$this->connection->createCommand('bad SQL');
+		$this->setExpectedException('CException');
+		$command->execute();
+	}
+
+	function testQuery()
+	{
+		$sql='SELECT * FROM posts';
+		$reader=$this->connection->createCommand($sql)->query();
+		$this->assertTrue($reader instanceof CDbDataReader);
+
+		$sql='SELECT * FROM posts';
+		$command=$this->connection->createCommand($sql);
+		$command->prepare();
+		$reader=$command->query();
+		$this->assertTrue($reader instanceof CDbDataReader);
+
+		$command=$this->connection->createCommand('bad SQL');
+		$this->setExpectedException('CException');
+		$command->query();
+	}
+
+	function testBindParam()
+	{
+		$sql='INSERT INTO posts(title,create_time,author_id) VALUES (:title, :create_time, 1)';
+		$command=$this->connection->createCommand($sql);
+		$title='test title';
+		$createTime=time();
+		$command->bindParam(':title',$title);
+		$command->bindParam(':create_time',$createTime);
+		$command->execute();
+
+		$sql='SELECT create_time FROM posts WHERE title=:title';
+		$command=$this->connection->createCommand($sql);
+		$command->bindParam(':title',$title);
+		$this->assertEquals($command->queryScalar(),$createTime);
+
+		$sql='INSERT INTO types (int_col, char_col, float_col, blob_col, numeric_col, bool_col) VALUES (:int_col, :char_col, :float_col, :blob_col, :numeric_col, :bool_col)';
+		$command=$this->connection->createCommand($sql);
+		$intCol=123;
+		$charCol='abc';
+		$floatCol=1.23;
+		$blobCol="\x10\x11\x12";
+		$numericCol='1.23';
+		$boolCol=false;
+		$command->bindParam(':int_col',$intCol);
+		$command->bindParam(':char_col',$charCol);
+		$command->bindParam(':float_col',$floatCol);
+		$command->bindParam(':blob_col',$blobCol);
+		$command->bindParam(':numeric_col',$numericCol);
+		$command->bindParam(':bool_col',$boolCol);
+		$this->assertEquals(1,$command->execute());
+
+		$sql='SELECT * FROM types';
+		$row=$this->connection->createCommand($sql)->queryRow();
+		$this->assertEquals($row['int_col'],$intCol);
+		$this->assertEquals($row['char_col'],$charCol);
+		$this->assertEquals($row['float_col'],$floatCol);
+		$this->assertEquals($row['blob_col'],$blobCol);
+		$this->assertEquals($row['numeric_col'],$numericCol);
+	}
+
+	function testBindValue()
+	{
+		$sql='INSERT INTO comments(content,post_id,author_id) VALUES (:content, 1, 1)';
+		$command=$this->connection->createCommand($sql);
+		$command->bindValue(':content','test comment');
+		$command->execute();
+
+		$sql='SELECT post_id FROM comments WHERE content=:content';
+		$command=$this->connection->createCommand($sql);
+		$command->bindValue(':content','test comment');
+		$this->assertEquals($command->queryScalar(),1);
+	}
+
+	function testQueryAll()
+	{
+		$rows=$this->connection->createCommand('SELECT * FROM posts')->queryAll();
+		$this->assertEquals(count($rows),5);
+		$row=$rows[2];
+		$this->assertEquals($row['id'],3);
+		$this->assertEquals($row['title'],'post 3');
+
+		$rows=$this->connection->createCommand('SELECT * FROM posts WHERE id=10')->queryAll();
+		$this->assertEquals($rows,array());
+	}
+
+	function testQueryRow()
+	{
+		$sql='SELECT * FROM posts';
+		$row=$this->connection->createCommand($sql)->queryRow();
+		$this->assertEquals($row['id'],1);
+		$this->assertEquals($row['title'],'post 1');
+
+		$sql='SELECT * FROM posts';
+		$command=$this->connection->createCommand($sql);
+		$command->prepare();
+		$row=$command->queryRow();
+		$this->assertEquals($row['id'],1);
+		$this->assertEquals($row['title'],'post 1');
+
+		$sql='SELECT * FROM posts WHERE id=10';
+		$command=$this->connection->createCommand($sql);
+		$this->assertFalse($command->queryRow());
+
+		$command=$this->connection->createCommand('bad SQL');
+		$this->setExpectedException('CException');
+		$command->queryRow();
+	}
+
+	function testQueryColumn()
+	{
+		$sql='SELECT * FROM posts';
+		$column=$this->connection->createCommand($sql)->queryColumn();
+		$this->assertEquals($column,range(1,5));
+
+		$command=$this->connection->createCommand('SELECT id FROM posts WHERE id=10');
+		$this->assertEquals($command->queryColumn(),array());
+
+		$command=$this->connection->createCommand('bad SQL');
+		$this->setExpectedException('CException');
+		$command->queryColumn();
+	}
+
+	function testQueryScalar()
+	{
+		$sql='SELECT * FROM posts';
+		$this->assertEquals($this->connection->createCommand($sql)->queryScalar(),1);
+
+		$sql='SELECT id FROM posts';
+		$command=$this->connection->createCommand($sql);
+		$command->prepare();
+		$this->assertEquals($command->queryScalar(),1);
+
+		$command=$this->connection->createCommand('SELECT id FROM posts WHERE id=10');
+		$this->assertFalse($command->queryScalar());
+
+		$command=$this->connection->createCommand('bad SQL');
+		$this->setExpectedException('CException');
+		$command->queryScalar();
+	}
+
+	function testFetchMode(){
+		$sql='SELECT * FROM posts';
+		$command=$this->connection->createCommand($sql);
+		$result = $command->queryRow();
+		$this->assertTrue(is_array($result));
+
+		$sql='SELECT * FROM posts';
+		$command=$this->connection->createCommand($sql);
+		$command->setFetchMode(PDO::FETCH_OBJ);
+		$result = $command->queryRow();
+		$this->assertTrue(is_object($result));
+	}
+	*/
+}
\ No newline at end of file
diff --git a/tests/unit/framework/db/dao/ConnectionTest.php b/tests/unit/framework/db/dao/ConnectionTest.php
index 3318065..d433303 100644
--- a/tests/unit/framework/db/dao/ConnectionTest.php
+++ b/tests/unit/framework/db/dao/ConnectionTest.php
@@ -85,57 +85,9 @@ class ConnectionTest extends TestCase
 
 	}
 
-
 	function createConnection()
 	{
 		$params = $this->getParam('mysql');
 		return new Connection($params['dsn'], $params['username'], $params['password']);
 	}
-
-	/*
-	function testCreateCommand()
-	{
-		$sql='SELECT * FROM posts';
-		$this->connection->active=true;
-		$this->connection->pdoInstance->exec(file_get_contents(dirname(__FILE__).'/data/sqlite.sql'));
-		$command=$this->connection->createCommand($sql);
-		$this->assertTrue($command instanceof CDbCommand);
-	}
-
-	function testLastInsertID()
-	{
-	    $this->connection->active=true;
-	    $this->connection->pdoInstance->exec(file_get_contents(dirname(__FILE__).'/data/sqlite.sql'));
-		$sql='INSERT INTO posts(title,create_time,author_id) VALUES(\'test post\',11000,1)';
-		$this->connection->createCommand($sql)->execute();
-		$this->assertEquals($this->connection->lastInsertID,6);
-	}
-
-	function testQuoteValue()
-	{
-	    $this->connection->active=true;
-	    $this->connection->pdoInstance->exec(file_get_contents(dirname(__FILE__).'/data/sqlite.sql'));
-		$str="this is 'my' name";
-		$expectedStr="'this is ''my'' name'";
-		$this->assertEquals($expectedStr,$this->connection->quoteValue($str));
-	}
-
-	function testColumnNameCase()
-	{
-	    $this->connection->active=true;
-	    $this->connection->pdoInstance->exec(file_get_contents(dirname(__FILE__).'/data/sqlite.sql'));
-		$this->assertEquals(PDO::CASE_NATURAL,$this->connection->ColumnCase);
-		$this->connection->columnCase=PDO::CASE_LOWER;
-		$this->assertEquals(PDO::CASE_LOWER,$this->connection->ColumnCase);
-	}
-
-	function testNullConversion()
-	{
-	    $this->connection->active=true;
-	    $this->connection->pdoInstance->exec(file_get_contents(dirname(__FILE__).'/data/sqlite.sql'));
-		$this->assertEquals(PDO::NULL_NATURAL,$this->connection->NullConversion);
-		$this->connection->nullConversion=PDO::NULL_EMPTY_STRING;
-		$this->assertEquals(PDO::NULL_EMPTY_STRING,$this->connection->NullConversion);
-	}
-	*/
 }