diff --git a/framework/db/Command.php b/framework/db/Command.php
index 8ae7912..90d7764 100644
--- a/framework/db/Command.php
+++ b/framework/db/Command.php
@@ -62,21 +62,6 @@ class Command extends \yii\base\Component
 	private $_params = array();
 
 	/**
-	 * Constructor.
-	 * @param Connection $connection the database connection
-	 * @param string $sql the SQL statement to be executed
-	 * @param array $params the parameters to be bound to the SQL statement
-	 * @param array $config name-value pairs that will be used to initialize the object properties
-	 */
-	public function __construct($connection, $sql = null, $params = array(), $config = array())
-	{
-		$this->connection = $connection;
-		$this->_sql = $sql;
-		$this->bindValues($params);
-		parent::__construct($config);
-	}
-
-	/**
 	 * Returns the SQL statement for this command.
 	 * @return string the SQL statement to be executed
 	 */
@@ -88,14 +73,26 @@ class Command extends \yii\base\Component
 	/**
 	 * Specifies the SQL statement to be executed.
 	 * Any previous execution will be terminated or cancelled.
-	 * @param string $value the SQL statement to be set.
+	 * @param string $sql the SQL statement to be set.
 	 * @return Command this command instance
 	 */
-	public function setSql($value)
+	public function setSql($sql)
 	{
-		$this->_sql = $value;
-		$this->_params = array();
-		$this->cancel();
+		if ($sql !== $this->_sql) {
+			if ($this->connection->enableAutoQuoting && $sql != '') {
+				$sql = preg_replace_callback('/(\\{\\{(.*?)\\}\\}|\\[\\[(.*?)\\]\\])/', function($matches) {
+					if (isset($matches[3])) {
+						return $this->connection->quoteColumnName($matches[3]);
+					} else {
+						$name = str_replace('%', $this->connection->tablePrefix, $matches[2]);
+						return $this->connection->quoteTableName($name);
+					}
+				}, $sql);
+			}
+			$this->_sql = $sql;
+			$this->_params = array();
+			$this->cancel();
+		}
 		return $this;
 	}
 
@@ -110,7 +107,7 @@ class Command extends \yii\base\Component
 	public function prepare()
 	{
 		if ($this->pdoStatement == null) {
-			$sql = $this->connection->expandTablePrefix($this->getSql());
+			$sql = $this->getSql();
 			try {
 				$this->pdoStatement = $this->connection->pdo->prepare($sql);
 			} catch (\Exception $e) {
@@ -223,7 +220,7 @@ class Command extends \yii\base\Component
 	 */
 	public function execute($params = array())
 	{
-		$sql = $this->connection->expandTablePrefix($this->getSql());
+		$sql = $this->getSql();
 		$this->_params = array_merge($this->_params, $params);
 		if ($this->_params === array()) {
 			$paramLog = '';
@@ -356,7 +353,7 @@ class Command extends \yii\base\Component
 	private function queryInternal($method, $params, $fetchMode = null)
 	{
 		$db = $this->connection;
-		$sql = $db->expandTablePrefix($this->getSql());
+		$sql = $this->getSql();
 		$this->_params = array_merge($this->_params, $params);
 		if ($this->_params === array()) {
 			$paramLog = '';
diff --git a/framework/db/Connection.php b/framework/db/Connection.php
index 7cc4e1b..c254943 100644
--- a/framework/db/Connection.php
+++ b/framework/db/Connection.php
@@ -124,7 +124,7 @@ class Connection extends \yii\base\ApplicationComponent
 	public $attributes;
 	/**
 	 * @var \PDO the PHP PDO instance associated with this DB connection.
-	 * This property is mainly managed by [[open]] and [[close]] methods.
+	 * This property is mainly managed by [[open()]] and [[close()]] methods.
 	 * When a DB connection is active, this property will represent a PDO instance;
 	 * otherwise, it will be null.
 	 */
@@ -132,7 +132,7 @@ class Connection extends \yii\base\ApplicationComponent
 	/**
 	 * @var boolean whether to enable schema caching.
 	 * Note that in order to enable truly schema caching, a valid cache component as specified
-	 * by [[schemaCacheID]] must be enabled and [[schemaCacheEnabled]] must be set true.
+	 * by [[schemaCacheID]] must be enabled and [[enableSchemaCache]] must be set true.
 	 * @see schemaCacheDuration
 	 * @see schemaCacheExclude
 	 * @see schemaCacheID
@@ -159,7 +159,7 @@ class Connection extends \yii\base\ApplicationComponent
 	/**
 	 * @var boolean whether to enable query caching.
 	 * Note that in order to enable query caching, a valid cache component as specified
-	 * by [[queryCacheID]] must be enabled and [[queryCacheEnabled]] must be set true.
+	 * by [[queryCacheID]] must be enabled and [[enableQueryCache]] must be set true.
 	 *
 	 * Methods [[beginCache()]] and [[endCache()]] can be used as shortcuts to turn on
 	 * and off query caching on the fly.
@@ -215,16 +215,24 @@ class Connection extends \yii\base\ApplicationComponent
 	 */
 	public $enableProfiling = false;
 	/**
-	 * @var string the default prefix for table names. Defaults to null, meaning not using table prefix.
-	 * By setting this property, any token like '{{TableName}}' in [[Command::sql]] will
-	 * be replaced with 'prefixTableName', where 'prefix' refers to this property value.
-	 * For example, '{{post}}' becomes 'tbl_post', if 'tbl_' is set as the table prefix.
-	 *
-	 * Note that if you set this property to be an empty string, then '{{post}}' will be replaced
-	 * with 'post'.
+	 * @var string the common prefix or suffix for table names. If a table name is given
+	 * as `{{%TableName}}`, then the percentage character `%` will be replaced with this
+	 * property value. For example, `{{%post}}` becomes `{{tbl_post}}` if this property is
+	 * set as `"tbl_"`. Note that this property is only effective when [[enableAutoQuoting]]
+	 * is true.
+	 * @see enableAutoQuoting
 	 */
 	public $tablePrefix;
 	/**
+	 * @var boolean whether to enable automatic quoting of table names and column names.
+	 * Defaults to true. When this property is true, any token enclosed within double curly brackets
+	 * (e.g. `{{post}}`) in a SQL statement will be treated as a table name and will be quoted
+	 * accordingly when the SQL statement is executed; and any token enclosed within double square
+	 * brackets (e.g. `[[name]]`) will be treated as a column name and quoted accordingly.
+	 * @see tablePrefix
+	 */
+	public $enableAutoQuoting = true;
+	/**
 	 * @var array a list of SQL statements that should be executed right after the DB connection is established.
 	 */
 	public $initSQLs;
@@ -411,7 +419,12 @@ class Connection extends \yii\base\ApplicationComponent
 	public function createCommand($sql = null, $params = array())
 	{
 		$this->open();
-		return new Command($this, $sql, $params);
+		$command = new Command(array(
+			'connection' => $this,
+			'sql' => $sql,
+		));
+		$command->bindValues($params);
+		return $command;
 	}
 
 	/**
@@ -513,43 +526,27 @@ class Connection extends \yii\base\ApplicationComponent
 	/**
 	 * Quotes a table name for use in a query.
 	 * If the table name contains schema prefix, the prefix will also be properly quoted.
+	 * If the table name is already quoted or contains special characters including '(', '[[' and '{{',
+	 * then this method will do nothing.
 	 * @param string $name table name
-	 * @param boolean $simple if this is true, then the method will assume $name is a table name without schema prefix.
 	 * @return string the properly quoted table name
 	 */
-	public function quoteTableName($name, $simple = false)
+	public function quoteTableName($name)
 	{
-		return $simple ? $this->getDriver()->quoteSimpleTableName($name) : $this->getDriver()->quoteTableName($name);
+		return $this->getDriver()->quoteTableName($name);
 	}
 
 	/**
 	 * Quotes a column name for use in a query.
-	 * If the column name contains table prefix, the prefix will also be properly quoted.
+	 * If the column name contains prefix, the prefix will also be properly quoted.
+	 * If the column name is already quoted or contains special characters including '(', '[[' and '{{',
+	 * then this method will do nothing.
 	 * @param string $name column name
-	 * @param boolean $simple if this is true, then the method will assume $name is a column name without table prefix.
 	 * @return string the properly quoted column name
 	 */
-	public function quoteColumnName($name, $simple = false)
-	{
-		return $simple ? $this->getDriver()->quoteSimpleColumnName($name) : $this->getDriver()->quoteColumnName($name);
-	}
-
-	/**
-	 * Prefixes table names in a SQL statement with [[tablePrefix]].
-	 * By calling this method, tokens like '{{TableName}}' in the given SQL statement will
-	 * be replaced with 'prefixTableName', where 'prefix' refers to [[tablePrefix]].
-	 * Note that if [[tablePrefix]] is null, this method will do nothing.
-	 * @param string $sql the SQL statement whose table names need to be prefixed with [[tablePrefix]].
-	 * @return string the expanded SQL statement
-	 * @see tablePrefix
-	 */
-	public function expandTablePrefix($sql)
+	public function quoteColumnName($name)
 	{
-		if ($this->tablePrefix !== null && strpos($sql, '{{') !== false) {
-			return preg_replace('/{{(.*?)}}/', $this->tablePrefix . '\1', $sql);
-		} else {
-			return $sql;
-		}
+		return $this->getDriver()->quoteColumnName($name);
 	}
 
 	/**
diff --git a/framework/db/Driver.php b/framework/db/Driver.php
index 4ad8d69..5dbe5fb 100644
--- a/framework/db/Driver.php
+++ b/framework/db/Driver.php
@@ -92,8 +92,7 @@ abstract class Driver extends \yii\base\Object
 		}
 
 		$db = $this->connection;
-
-		$realName = $db->expandTablePrefix($name);
+		$realName = $this->getRealTableName($name);
 
 		/** @var $cache \yii\caching\Cache */
 		if ($db->enableSchemaCache && ($cache = \Yii::$application->getComponent($db->schemaCacheID)) !== null && !in_array($name, $db->schemaCacheExclude, true)) {
@@ -168,37 +167,57 @@ abstract class Driver extends \yii\base\Object
 
 	/**
 	 * Refreshes the schema.
-	 * This method cleans up the cached table schema and names
-	 * so that they can be recreated to reflect the database schema change.
-	 * @param string $tableName the name of the table that needs to be refreshed.
-	 * If null, all currently loaded tables will be refreshed.
+	 * This method cleans up all cached table schemas so that they can be re-created later
+	 * to reflect the database schema change.
 	 */
-	public function refresh($tableName = null)
+	public function refresh()
 	{
-		$db = $this->connection;
 		/** @var $cache \yii\caching\Cache */
-		if ($db->enableSchemaCache && ($cache = \Yii::$application->getComponent($db->schemaCacheID)) !== null) {
-			if ($tableName === null) {
-				foreach ($this->_tables as $name => $table) {
-					$cache->delete($this->getCacheKey($name));
-				}
-				$this->_tables = array();
-			} else {
-				$cache->delete($this->getCacheKey($tableName));
-				unset($this->_tables[$tableName]);
+		if ($this->connection->enableSchemaCache && ($cache = \Yii::$application->getComponent($this->connection->schemaCacheID)) !== null) {
+			foreach ($this->_tables as $name => $table) {
+				$cache->delete($this->getCacheKey($name));
 			}
 		}
+		$this->_tables = array();
+	}
+
+	/**
+	 * Creates a query builder for the database.
+	 * This method may be overridden by child classes to create a DBMS-specific query builder.
+	 * @return QueryBuilder query builder instance
+	 */
+	public function createQueryBuilder()
+	{
+		return new QueryBuilder($this->connection);
+	}
+
+	/**
+	 * Returns all table names in the database.
+	 * This method should be overridden by child classes in order to support this feature
+	 * because the default implementation simply throws an exception.
+	 * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
+	 * If not empty, the returned table names will be prefixed with the schema name.
+	 * @return array all table names in the database.
+	 */
+	protected function findTableNames($schema = '')
+	{
+		throw new Exception(get_class($this) . ' does not support fetching all table names.');
 	}
 
 	/**
 	 * Quotes a table name for use in a query.
 	 * If the table name contains schema prefix, the prefix will also be properly quoted.
+	 * If the table name is already quoted or contains special characters including '(', '[[' and '{{',
+	 * then this method will do nothing.
 	 * @param string $name table name
 	 * @return string the properly quoted table name
 	 * @see quoteSimpleTableName
 	 */
 	public function quoteTableName($name)
 	{
+		if (strpos($name, '(') !== false || strpos($name, '[[') !== false || strpos($name, '{{') !== false) {
+			return $name;
+		}
 		if (strpos($name, '.') === false) {
 			return $this->quoteSimpleTableName($name);
 		}
@@ -211,25 +230,19 @@ abstract class Driver extends \yii\base\Object
 	}
 
 	/**
-	 * Quotes a simple table name for use in a query.
-	 * A simple table name does not schema prefix.
-	 * @param string $name table name
-	 * @return string the properly quoted table name
-	 */
-	public function quoteSimpleTableName($name)
-	{
-		return strpos($name, "'") !== false ? $name : "'" . $name . "'";
-	}
-
-	/**
 	 * Quotes a column name for use in a query.
 	 * If the column name contains prefix, the prefix will also be properly quoted.
+	 * If the column name is already quoted or contains special characters including '(', '[[' and '{{',
+	 * then this method will do nothing.
 	 * @param string $name column name
 	 * @return string the properly quoted column name
 	 * @see quoteSimpleColumnName
 	 */
 	public function quoteColumnName($name)
 	{
+		if (strpos($name, '(') !== false || strpos($name, '[[') !== false || strpos($name, '{{') !== false) {
+			return $name;
+		}
 		if (($pos = strrpos($name, '.')) !== false) {
 			$prefix = $this->quoteTableName(substr($name, 0, $pos)) . '.';
 			$name = substr($name, $pos + 1);
@@ -240,36 +253,43 @@ abstract class Driver extends \yii\base\Object
 	}
 
 	/**
-	 * Quotes a simple column name for use in a query.
-	 * A simple column name does not contain prefix.
-	 * @param string $name column name
-	 * @return string the properly quoted column name
+	 * Quotes a simple table name for use in a query.
+	 * A simple table name should contain the table name only without any schema prefix.
+	 * If the table name is already quoted, this method will do nothing.
+	 * @param string $name table name
+	 * @return string the properly quoted table name
 	 */
-	public function quoteSimpleColumnName($name)
+	public function quoteSimpleTableName($name)
 	{
-		return strpos($name, '"') !== false || $name === '*' ? $name : '"' . $name . '"';
+		return strpos($name, "'") !== false ? $name : "'" . $name . "'";
 	}
 
 	/**
-	 * Creates a query builder for the database.
-	 * This method may be overridden by child classes to create a DBMS-specific query builder.
-	 * @return QueryBuilder query builder instance
+	 * Quotes a simple column name for use in a query.
+	 * A simple column name should contain the column name only without any prefix.
+	 * If the column name is already quoted or is the asterisk character '*', this method will do nothing.
+	 * @param string $name column name
+	 * @return string the properly quoted column name
 	 */
-	public function createQueryBuilder()
+	public function quoteSimpleColumnName($name)
 	{
-		return new QueryBuilder($this->connection);
+		return strpos($name, '"') !== false || $name === '*' ? $name : '"' . $name . '"';
 	}
 
 	/**
-	 * Returns all table names in the database.
-	 * This method should be overridden by child classes in order to support this feature
-	 * because the default implementation simply throws an exception.
-	 * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
-	 * If not empty, the returned table names will be prefixed with the schema name.
-	 * @return array all table names in the database.
+	 * Returns the real name of a table name.
+	 * This method will strip off curly brackets from the given table name
+	 * and replace the percentage character in the name with [[Connection::tablePrefix]].
+	 * @param string $name the table name to be converted
+	 * @return string the real name of the given table name
 	 */
-	protected function findTableNames($schema = '')
+	public function getRealTableName($name)
 	{
-		throw new Exception(get_class($this) . 'does not support fetching all table names.');
+		if ($this->connection->enableAutoQuoting && strpos($name, '{{') !== false) {
+			$name = preg_replace('/\\{\\{(.*?)\\}\\}/', '\1', $name);
+			return str_replace('%', $this->connection->tablePrefix, $name);
+		} else {
+			return $name;
+		}
 	}
 }
diff --git a/framework/db/QueryBuilder.php b/framework/db/QueryBuilder.php
index d038076..86ec501 100644
--- a/framework/db/QueryBuilder.php
+++ b/framework/db/QueryBuilder.php
@@ -32,10 +32,6 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public $separator = " ";
 	/**
-	 * @var boolean whether to automatically quote table and column names when generating SQL statements.
-	 */
-	public $autoQuote = true;
-	/**
 	 * @var array the abstract column types mapped to physical column types.
 	 * This is mainly used to support creating/modifying tables using DB-independent data type specifications.
 	 * Child classes should override this property to declare supported type mappings.
@@ -99,7 +95,7 @@ class QueryBuilder extends \yii\base\Object
 		$placeholders = array();
 		$count = 0;
 		foreach ($columns as $name => $value) {
-			$names[] = $this->quoteColumnName($name);
+			$names[] = $this->connection->quoteColumnName($name);
 			if ($value instanceof Expression) {
 				$placeholders[] = $value->expression;
 				foreach ($value->params as $n => $v) {
@@ -112,7 +108,7 @@ class QueryBuilder extends \yii\base\Object
 			}
 		}
 
-		return 'INSERT INTO ' . $this->quoteTableName($table)
+		return 'INSERT INTO ' . $this->connection->quoteTableName($table)
 			. ' (' . implode(', ', $names) . ') VALUES ('
 			. implode(', ', $placeholders) . ')';
 	}
@@ -144,17 +140,17 @@ class QueryBuilder extends \yii\base\Object
 		$count = 0;
 		foreach ($columns as $name => $value) {
 			if ($value instanceof Expression) {
-				$lines[] = $this->quoteColumnName($name, true) . '=' . $value->expression;
+				$lines[] = $this->connection->quoteColumnName($name) . '=' . $value->expression;
 				foreach ($value->params as $n => $v) {
 					$params[$n] = $v;
 				}
 			} else {
-				$lines[] = $this->quoteColumnName($name, true) . '=:p' . $count;
+				$lines[] = $this->connection->quoteColumnName($name) . '=:p' . $count;
 				$params[':p' . $count] = $value;
 				$count++;
 			}
 		}
-		$sql = 'UPDATE ' . $this->quoteTableName($table) . ' SET ' . implode(', ', $lines);
+		$sql = 'UPDATE ' . $this->connection->quoteTableName($table) . ' SET ' . implode(', ', $lines);
 		if (($where = $this->buildCondition($condition)) !== '') {
 			$sql .= ' WHERE ' . $where;
 		}
@@ -179,7 +175,7 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function delete($table, $condition = '')
 	{
-		$sql = 'DELETE FROM ' . $this->quoteTableName($table);
+		$sql = 'DELETE FROM ' . $this->connection->quoteTableName($table);
 		if (($where = $this->buildCondition($condition)) !== '') {
 			$sql .= ' WHERE ' . $where;
 		}
@@ -217,12 +213,12 @@ class QueryBuilder extends \yii\base\Object
 		$cols = array();
 		foreach ($columns as $name => $type) {
 			if (is_string($name)) {
-				$cols[] = "\t" . $this->quoteColumnName($name) . ' ' . $this->getColumnType($type);
+				$cols[] = "\t" . $this->connection->quoteColumnName($name) . ' ' . $this->getColumnType($type);
 			} else {
 				$cols[] = "\t" . $type;
 			}
 		}
-		$sql = "CREATE TABLE " . $this->quoteTableName($table) . " (\n" . implode(",\n", $cols) . "\n)";
+		$sql = "CREATE TABLE " . $this->connection->quoteTableName($table) . " (\n" . implode(",\n", $cols) . "\n)";
 		return $options === null ? $sql : $sql . ' ' . $options;
 	}
 
@@ -234,7 +230,7 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function renameTable($oldName, $newName)
 	{
-		return 'RENAME TABLE ' . $this->quoteTableName($oldName) . ' TO ' . $this->quoteTableName($newName);
+		return 'RENAME TABLE ' . $this->connection->quoteTableName($oldName) . ' TO ' . $this->connection->quoteTableName($newName);
 	}
 
 	/**
@@ -244,7 +240,7 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function dropTable($table)
 	{
-		return "DROP TABLE " . $this->quoteTableName($table);
+		return "DROP TABLE " . $this->connection->quoteTableName($table);
 	}
 
 	/**
@@ -254,7 +250,7 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function truncateTable($table)
 	{
-		return "TRUNCATE TABLE " . $this->quoteTableName($table);
+		return "TRUNCATE TABLE " . $this->connection->quoteTableName($table);
 	}
 
 	/**
@@ -268,8 +264,8 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function addColumn($table, $column, $type)
 	{
-		return 'ALTER TABLE ' . $this->quoteTableName($table)
-			. ' ADD ' . $this->quoteColumnName($column) . ' '
+		return 'ALTER TABLE ' . $this->connection->quoteTableName($table)
+			. ' ADD ' . $this->connection->quoteColumnName($column) . ' '
 			. $this->getColumnType($type);
 	}
 
@@ -281,8 +277,8 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function dropColumn($table, $column)
 	{
-		return "ALTER TABLE " . $this->quoteTableName($table)
-			. " DROP COLUMN " . $this->quoteColumnName($column, true);
+		return "ALTER TABLE " . $this->connection->quoteTableName($table)
+			. " DROP COLUMN " . $this->connection->quoteColumnName($column);
 	}
 
 	/**
@@ -294,9 +290,9 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function renameColumn($table, $oldName, $newName)
 	{
-		return "ALTER TABLE " . $this->quoteTableName($table)
-			. " RENAME COLUMN " . $this->quoteColumnName($oldName, true)
-			. " TO " . $this->quoteColumnName($newName, true);
+		return "ALTER TABLE " . $this->connection->quoteTableName($table)
+			. " RENAME COLUMN " . $this->connection->quoteColumnName($oldName)
+			. " TO " . $this->connection->quoteColumnName($newName);
 	}
 
 	/**
@@ -311,9 +307,9 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function alterColumn($table, $column, $type)
 	{
-		return 'ALTER TABLE ' . $this->quoteTableName($table) . ' CHANGE '
-			. $this->quoteColumnName($column, true) . ' '
-			. $this->quoteColumnName($column, true) . ' '
+		return 'ALTER TABLE ' . $this->connection->quoteTableName($table) . ' CHANGE '
+			. $this->connection->quoteColumnName($column) . ' '
+			. $this->connection->quoteColumnName($column) . ' '
 			. $this->getColumnType($type);
 	}
 
@@ -333,10 +329,10 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function addForeignKey($name, $table, $columns, $refTable, $refColumns, $delete = null, $update = null)
 	{
-		$sql = 'ALTER TABLE ' . $this->quoteTableName($table)
-			. ' ADD CONSTRAINT ' . $this->quoteColumnName($name)
+		$sql = 'ALTER TABLE ' . $this->connection->quoteTableName($table)
+			. ' ADD CONSTRAINT ' . $this->connection->quoteColumnName($name)
 			. ' FOREIGN KEY (' . $this->buildColumns($columns) . ')'
-			. ' REFERENCES ' . $this->quoteTableName($refTable)
+			. ' REFERENCES ' . $this->connection->quoteTableName($refTable)
 			. ' (' . $this->buildColumns($refColumns) . ')';
 		if ($delete !== null) {
 			$sql .= ' ON DELETE ' . $delete;
@@ -355,8 +351,8 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function dropForeignKey($name, $table)
 	{
-		return 'ALTER TABLE ' . $this->quoteTableName($table)
-			. ' DROP CONSTRAINT ' . $this->quoteColumnName($name);
+		return 'ALTER TABLE ' . $this->connection->quoteTableName($table)
+			. ' DROP CONSTRAINT ' . $this->connection->quoteColumnName($name);
 	}
 
 	/**
@@ -372,8 +368,8 @@ class QueryBuilder extends \yii\base\Object
 	public function createIndex($name, $table, $columns, $unique = false)
 	{
 		return ($unique ? 'CREATE UNIQUE INDEX ' : 'CREATE INDEX ')
-			. $this->quoteTableName($name) . ' ON '
-			. $this->quoteTableName($table)
+			. $this->connection->quoteTableName($name) . ' ON '
+			. $this->connection->quoteTableName($table)
 			. ' (' . $this->buildColumns($columns) . ')';
 	}
 
@@ -385,7 +381,7 @@ class QueryBuilder extends \yii\base\Object
 	 */
 	public function dropIndex($name, $table)
 	{
-		return 'DROP INDEX ' . $this->quoteTableName($name) . ' ON ' . $this->quoteTableName($table);
+		return 'DROP INDEX ' . $this->connection->quoteTableName($name) . ' ON ' . $this->connection->quoteTableName($table);
 	}
 
 	/**
@@ -500,7 +496,7 @@ class QueryBuilder extends \yii\base\Object
 				$parts[] = $this->buildInCondition('in', array($column, $value));
 			} else {
 				if (strpos($column, '(') === false) {
-					$column = $this->quoteColumnName($column);
+					$column = $this->connection->quoteColumnName($column);
 				}
 				if ($value === null) {
 					$parts[] = "$column IS NULL";
@@ -541,7 +537,7 @@ class QueryBuilder extends \yii\base\Object
 		list($column, $value1, $value2) = $operands;
 
 		if (strpos($column, '(') === false) {
-			$column = $this->quoteColumnName($column);
+			$column = $this->connection->quoteColumnName($column);
 		}
 		$value1 = is_string($value1) ? $this->connection->quoteValue($value1) : (string)$value1;
 		$value2 = is_string($value2) ? $this->connection->quoteValue($value2) : (string)$value2;
@@ -581,7 +577,7 @@ class QueryBuilder extends \yii\base\Object
 			}
 		}
 		if (strpos($column, '(') === false) {
-			$column = $this->quoteColumnName($column);
+			$column = $this->connection->quoteColumnName($column);
 		}
 
 		if (count($values) > 1) {
@@ -596,7 +592,7 @@ class QueryBuilder extends \yii\base\Object
 	{
 		foreach ($columns as $i => $column) {
 			if (strpos($column, '(') === false) {
-				$columns[$i] = $this->quoteColumnName($column);
+				$columns[$i] = $this->connection->quoteColumnName($column);
 			}
 		}
 		$vss = array();
@@ -636,7 +632,7 @@ class QueryBuilder extends \yii\base\Object
 		}
 
 		if (strpos($column, '(') === false) {
-			$column = $this->quoteColumnName($column);
+			$column = $this->connection->quoteColumnName($column);
 		}
 
 		$parts = array();
@@ -664,24 +660,21 @@ class QueryBuilder extends \yii\base\Object
 			return $select . ' *';
 		}
 
-		if ($this->autoQuote) {
-			$driver = $this->connection->driver;
-			if (!is_array($columns)) {
-				if (strpos($columns, '(') !== false) {
-					return $select . ' ' . $columns;
-				} else {
-					$columns = preg_split('/\s*,\s*/', trim($columns), -1, PREG_SPLIT_NO_EMPTY);
-				}
+		if (!is_array($columns)) {
+			if (strpos($columns, '(') !== false) {
+				return $select . ' ' . $columns;
+			} else {
+				$columns = preg_split('/\s*,\s*/', trim($columns), -1, PREG_SPLIT_NO_EMPTY);
 			}
-			foreach ($columns as $i => $column) {
-				if (is_object($column)) {
-					$columns[$i] = (string)$column;
-				} elseif (strpos($column, '(') === false) {
-					if (preg_match('/^(.*?)(?i:\s+as\s+|\s+)([\w\-_\.]+)$/', $column, $matches)) {
-						$columns[$i] = $driver->quoteColumnName($matches[1]) . ' AS ' . $driver->quoteSimpleColumnName($matches[2]);
-					} else {
-						$columns[$i] = $driver->quoteColumnName($column);
-					}
+		}
+		foreach ($columns as $i => $column) {
+			if (is_object($column)) {
+				$columns[$i] = (string)$column;
+			} elseif (strpos($column, '(') === false) {
+				if (preg_match('/^(.*?)(?i:\s+as\s+|\s+)([\w\-_\.]+)$/', $column, $matches)) {
+					$columns[$i] = $this->connection->quoteColumnName($matches[1]) . ' AS ' . $this->connection->quoteColumnName($matches[2]);
+				} else {
+					$columns[$i] = $this->connection->quoteColumnName($column);
 				}
 			}
 		}
@@ -703,22 +696,19 @@ class QueryBuilder extends \yii\base\Object
 			return '';
 		}
 
-		if ($this->autoQuote) {
-			$driver = $this->connection->driver;
-			if (!is_array($tables)) {
-				if (strpos($tables, '(') !== false) {
-					return 'FROM ' . $tables;
-				} else {
-					$tables = preg_split('/\s*,\s*/', trim($tables), -1, PREG_SPLIT_NO_EMPTY);
-				}
+		if (!is_array($tables)) {
+			if (strpos($tables, '(') !== false) {
+				return 'FROM ' . $tables;
+			} else {
+				$tables = preg_split('/\s*,\s*/', trim($tables), -1, PREG_SPLIT_NO_EMPTY);
 			}
-			foreach ($tables as $i => $table) {
-				if (strpos($table, '(') === false) {
-					if (preg_match('/^(.*?)(?i:\s+as\s+|\s+)(.*)$/i', $table, $matches)) { // with alias
-						$tables[$i] = $driver->quoteTableName($matches[1]) . ' ' . $driver->quoteTableName($matches[2]);
-					} else {
-						$tables[$i] = $driver->quoteTableName($table);
-					}
+		}
+		foreach ($tables as $i => $table) {
+			if (strpos($table, '(') === false) {
+				if (preg_match('/^(.*?)(?i:\s+as\s+|\s+)(.*)$/i', $table, $matches)) { // with alias
+					$tables[$i] = $this->connection->quoteTableName($matches[1]) . ' ' . $this->connection->quoteTableName($matches[2]);
+				} else {
+					$tables[$i] = $this->connection->quoteTableName($table);
 				}
 			}
 		}
@@ -747,12 +737,11 @@ class QueryBuilder extends \yii\base\Object
 			if (is_array($join)) { // 0:join type, 1:table name, 2:on-condition
 				if (isset($join[0], $join[1])) {
 					$table = $join[1];
-					if ($this->autoQuote && strpos($table, '(') === false) {
-						$driver = $this->connection->driver;
+					if (strpos($table, '(') === false) {
 						if (preg_match('/^(.*?)(?i:\s+as\s+|\s+)(.*)$/', $table, $matches)) { // with alias
-							$table = $driver->quoteTableName($matches[1]) . ' ' . $driver->quoteTableName($matches[2]);
+							$table = $this->connection->quoteTableName($matches[1]) . ' ' . $this->connection->quoteTableName($matches[2]);
 						} else {
-							$table = $driver->quoteTableName($table);
+							$table = $this->connection->quoteTableName($table);
 						}
 					}
 					$joins[$i] = $join[0] . ' ' . $table;
@@ -813,24 +802,21 @@ class QueryBuilder extends \yii\base\Object
 		if (empty($columns)) {
 			return '';
 		}
-		if ($this->autoQuote) {
-			$driver = $this->connection->driver;
-			if (!is_array($columns)) {
-				if (strpos($columns, '(') !== false) {
-					return 'ORDER BY ' . $columns;
-				} else {
-					$columns = preg_split('/\s*,\s*/', trim($columns), -1, PREG_SPLIT_NO_EMPTY);
-				}
+		if (!is_array($columns)) {
+			if (strpos($columns, '(') !== false) {
+				return 'ORDER BY ' . $columns;
+			} else {
+				$columns = preg_split('/\s*,\s*/', trim($columns), -1, PREG_SPLIT_NO_EMPTY);
 			}
-			foreach ($columns as $i => $column) {
-				if (is_object($column)) {
-					$columns[$i] = (string)$column;
-				} elseif (strpos($column, '(') === false) {
-					if (preg_match('/^(.*?)\s+(asc|desc)$/i', $column, $matches)) {
-						$columns[$i] = $driver->quoteColumnName($matches[1]) . ' ' . $matches[2];
-					} else {
-						$columns[$i] = $driver->quoteColumnName($column);
-					}
+		}
+		foreach ($columns as $i => $column) {
+			if (is_object($column)) {
+				$columns[$i] = (string)$column;
+			} elseif (strpos($column, '(') === false) {
+				if (preg_match('/^(.*?)\s+(asc|desc)$/i', $column, $matches)) {
+					$columns[$i] = $this->connection->quoteColumnName($matches[1]) . ' ' . $matches[2];
+				} else {
+					$columns[$i] = $this->connection->quoteColumnName($column);
 				}
 			}
 		}
@@ -879,61 +865,26 @@ class QueryBuilder extends \yii\base\Object
 
 	/**
 	 * Processes columns and properly quote them if necessary.
-	 * This method will quote columns if [[autoQuote]] is true.
 	 * It will join all columns into a string with comma as separators.
 	 * @param string|array $columns the columns to be processed
 	 * @return string the processing result
 	 */
 	protected function buildColumns($columns)
 	{
-		if ($this->autoQuote) {
-			if (!is_array($columns)) {
-				if (strpos($columns, '(') !== false) {
-					return $columns;
-				} else {
-					$columns = preg_split('/\s*,\s*/', $columns, -1, PREG_SPLIT_NO_EMPTY);
-				}
+		if (!is_array($columns)) {
+			if (strpos($columns, '(') !== false) {
+				return $columns;
+			} else {
+				$columns = preg_split('/\s*,\s*/', $columns, -1, PREG_SPLIT_NO_EMPTY);
 			}
-			foreach ($columns as $i => $column) {
-				if (is_object($column)) {
-					$columns[$i] = (string)$column;
-				} elseif (strpos($column, '(') === false) {
-					$columns[$i] = $this->quoteColumnName($column);
-				}
+		}
+		foreach ($columns as $i => $column) {
+			if (is_object($column)) {
+				$columns[$i] = (string)$column;
+			} elseif (strpos($column, '(') === false) {
+				$columns[$i] = $this->connection->quoteColumnName($column);
 			}
 		}
 		return is_array($columns) ? implode(', ', $columns) : $columns;
 	}
-
-	/**
-	 * Quotes a table name for use in a query.
-	 * This method will perform name quoting only when [[autoQuote]] is true.
-	 * @param string $name table name
-	 * @param boolean $simple whether the name should be treated as a simple table name without any prefix.
-	 * @return string the properly quoted table name
-	 */
-	protected function quoteTableName($name, $simple = false)
-	{
-		if ($this->autoQuote) {
-			return $this->connection->quoteTableName($name, $simple);
-		} else {
-			return $name;
-		}
-	}
-
-	/**
-	 * Quotes a column name for use in a query.
-	 * This method will perform name quoting only when [[autoQuote]] is true.
-	 * @param string $name column name
-	 * @param boolean $simple whether the name should be treated as a simple column name without any prefix.
-	 * @return string the properly quoted column name
-	 */
-	protected function quoteColumnName($name, $simple = false)
-	{
-		if ($this->autoQuote) {
-			return $this->connection->quoteColumnName($name, $simple);
-		} else {
-			return $name;
-		}
-	}
 }
diff --git a/framework/db/mysql/QueryBuilder.php b/framework/db/mysql/QueryBuilder.php
index 41cbc2c..7da3173 100644
--- a/framework/db/mysql/QueryBuilder.php
+++ b/framework/db/mysql/QueryBuilder.php
@@ -46,10 +46,11 @@ class QueryBuilder extends \yii\db\QueryBuilder
 	 * @param string $oldName the old name of the column. The name will be properly quoted by the method.
 	 * @param string $newName the new name of the column. The name will be properly quoted by the method.
 	 * @return string the SQL statement for renaming a DB column.
+	 * @throws Exception
 	 */
 	public function renameColumn($table, $oldName, $newName)
 	{
-		$quotedTable = $this->quoteTableName($table);
+		$quotedTable = $this->connection->quoteTableName($table);
 		$row = $this->connection->createCommand('SHOW CREATE TABLE ' . $quotedTable)->queryRow();
 		if ($row === false) {
 			throw new Exception("Unable to find '$oldName' in table '$table'.");
@@ -64,16 +65,16 @@ class QueryBuilder extends \yii\db\QueryBuilder
 			foreach ($matches[1] as $i => $c) {
 				if ($c === $oldName) {
 					return "ALTER TABLE $quotedTable CHANGE "
-						. $this->quoteColumnName($oldName, true) . ' '
-						. $this->quoteColumnName($newName, true) . ' '
+						. $this->connection->quoteColumnName($oldName) . ' '
+						. $this->connection->quoteColumnName($newName) . ' '
 						. $matches[2][$i];
 				}
 			}
 		}
 		// try to give back a SQL anyway
 		return "ALTER TABLE $quotedTable CHANGE "
-			. $this->quoteColumnName($oldName, true) . ' '
-			. $this->quoteColumnName($newName, true);
+			. $this->connection->quoteColumnName($oldName) . ' '
+			. $this->connection->quoteColumnName($newName);
 	}
 
 	/**
@@ -84,7 +85,7 @@ class QueryBuilder extends \yii\db\QueryBuilder
 	 */
 	public function dropForeignKey($name, $table)
 	{
-		return 'ALTER TABLE ' . $this->quoteTableName($table)
-			. ' DROP FOREIGN KEY ' . $this->quoteColumnName($name);
+		return 'ALTER TABLE ' . $this->connection->quoteTableName($table)
+			. ' DROP FOREIGN KEY ' . $this->connection->quoteColumnName($name);
 	}
 }
diff --git a/tests/unit/framework/db/CommandTest.php b/tests/unit/framework/db/CommandTest.php
index cd3c273..a55a016 100644
--- a/tests/unit/framework/db/CommandTest.php
+++ b/tests/unit/framework/db/CommandTest.php
@@ -36,6 +36,15 @@ class CommandTest extends \yiiunit\MysqlTestCase
 		$this->assertEquals($sql2, $command->sql);
 	}
 
+	function testAutoQuoting()
+	{
+		$db = $this->getConnection(false);
+
+		$sql = 'SELECT [[id]], [[t.name]] FROM {{tbl_customer}} t';
+		$command = $db->createCommand($sql);
+		$this->assertEquals("SELECT `id`, `t`.`name` FROM `tbl_customer` t", $command->sql);
+	}
+
 	function testPrepareCancel()
 	{
 		$db = $this->getConnection(false);
diff --git a/tests/unit/framework/db/ConnectionTest.php b/tests/unit/framework/db/ConnectionTest.php
index 7f3482c..e035eb2 100644
--- a/tests/unit/framework/db/ConnectionTest.php
+++ b/tests/unit/framework/db/ConnectionTest.php
@@ -49,7 +49,7 @@ class ConnectionTest extends \yiiunit\MysqlTestCase
 		$connection = $this->getConnection(false);
 		$this->assertEquals(123, $connection->quoteValue(123));
 		$this->assertEquals("'string'", $connection->quoteValue('string'));
-		$this->assertEquals("'It\'s interesting'", $connection->quoteValue("It's interesting"));
+		$this->assertEquals("'It\\'s interesting'", $connection->quoteValue("It's interesting"));
 	}
 
 	function testQuoteTableName()
@@ -58,7 +58,10 @@ class ConnectionTest extends \yiiunit\MysqlTestCase
 		$this->assertEquals('`table`', $connection->quoteTableName('table'));
 		$this->assertEquals('`table`', $connection->quoteTableName('`table`'));
 		$this->assertEquals('`schema`.`table`', $connection->quoteTableName('schema.table'));
-		$this->assertEquals('`schema.table`', $connection->quoteTableName('schema.table', true));
+		$this->assertEquals('`schema`.`table`', $connection->quoteTableName('schema.`table`'));
+		$this->assertEquals('[[table]]', $connection->quoteTableName('[[table]]'));
+		$this->assertEquals('{{table}}', $connection->quoteTableName('{{table}}'));
+		$this->assertEquals('(table)', $connection->quoteTableName('(table)'));
 	}
 
 	function testQuoteColumnName()
@@ -67,7 +70,10 @@ class ConnectionTest extends \yiiunit\MysqlTestCase
 		$this->assertEquals('`column`', $connection->quoteColumnName('column'));
 		$this->assertEquals('`column`', $connection->quoteColumnName('`column`'));
 		$this->assertEquals('`table`.`column`', $connection->quoteColumnName('table.column'));
-		$this->assertEquals('`table.column`', $connection->quoteColumnName('table.column', true));
+		$this->assertEquals('`table`.`column`', $connection->quoteColumnName('table.`column`'));
+		$this->assertEquals('[[column]]', $connection->quoteColumnName('[[column]]'));
+		$this->assertEquals('{{column}}', $connection->quoteColumnName('{{column}}'));
+		$this->assertEquals('(column)', $connection->quoteColumnName('(column)'));
 	}
 
 	function testGetPdoType()