diff --git a/framework/db/dao/ColumnSchema.php b/framework/db/dao/ColumnSchema.php
index 3b4e413..dd7256a 100644
--- a/framework/db/dao/ColumnSchema.php
+++ b/framework/db/dao/ColumnSchema.php
@@ -8,13 +8,15 @@
  * @license http://www.yiiframework.com/license/
  */
 
+namespace yii\db\dao;
+
 /**
  * ColumnSchema class describes the column meta data of a database table.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
  */
-class ColumnSchema extends CComponent
+class ColumnSchema extends \yii\base\Component
 {
 	/**
 	 * @var string name of this column (without quotes).
@@ -30,7 +32,7 @@ class ColumnSchema extends CComponent
 	public $allowNull;
 	/**
 	 * @var string logical type of this column. Possible logic types include:
-	 * string, text, boolean, integer, float, decimal, datetime, timestamp, time, date, binary
+	 * string, text, boolean, smallint, integer, bigint, float, decimal, datetime, timestamp, time, date, binary
 	 */
 	public $type;
 	/**
@@ -47,6 +49,10 @@ class ColumnSchema extends CComponent
 	 */
 	public $defaultValue;
 	/**
+	 * @var array enumerable values
+	 */
+	public $enumValues;
+	/**
 	 * @var integer size of the column.
 	 */
 	public $size;
@@ -63,69 +69,37 @@ class ColumnSchema extends CComponent
 	 */
 	public $isPrimaryKey;
 	/**
-	 * @var boolean whether this column is a foreign key
-	 */
-	public $isForeignKey;
-	/**
 	 * @var boolean whether this column is auto-incremental
 	 */
 	public $autoIncrement = false;
-
-
 	/**
-	 * Initializes the column with its DB type and default value.
-	 * This sets up the column's PHP type, size, precision, scale as well as default value.
-	 * @param string $dbType the column's DB type
-	 * @param mixed $defaultValue the default value
+	 * @var boolean whether this column is unsigned. This is only meaningful
+	 * when [[type]] is `integer` or `bigint`.
 	 */
-	public function init($dbType, $defaultValue)
-	{
-		$this->dbType = $dbType;
-		$this->extractType($dbType);
-		$this->extractLimit($dbType);
-		if ($defaultValue !== null)
-			$this->extractDefault($defaultValue);
-	}
+	public $unsigned;
 
 	/**
 	 * Extracts the PHP type from DB type.
-	 * @param string $dbType DB type
-	 */
-	protected function extractType($dbType)
-	{
-		if (stripos($dbType, 'int') !== false && stripos($dbType, 'unsigned int') === false)
-			$this->type = 'integer';
-		elseif (stripos($dbType, 'bool') !== false)
-			$this->type = 'boolean';
-		elseif (preg_match('/(real|floa|doub)/i', $dbType))
-			$this->type = 'double';
-		else
-			$this->type = 'string';
-	}
-
-	/**
-	 * Extracts size, precision and scale information from column's DB type.
-	 * @param string $dbType the column's DB type
 	 */
-	protected function extractLimit($dbType)
+	protected function getPhpType()
 	{
-		if (strpos($dbType, '(') && preg_match('/\((.*)\)/', $dbType, $matches))
-		{
-			$values = explode(',', $matches[1]);
-			$this->size = $this->precision = (int)$values[0];
-			if (isset($values[1]))
-				$this->scale = (int)$values[1];
+		static $typeMap = array( // logical type => php type
+			'smallint' => 'integer',
+	        'integer' => 'integer',
+	        'bigint' => 'integer',
+	        'boolean' => 'boolean',
+	        'float' => 'double',
+		);
+		if (isset($typeMap[$this->type])) {
+			if ($this->type === 'bigint') {
+				return PHP_INT_SIZE == 8 && !$this->unsigned ? 'integer' : 'string';
+			}
+			elseif ($this->type === 'integer') {
+				return PHP_INT_SIZE == 4 && $this->unsigned ? 'string' : 'integer';
+			}
+			return $typeMap[$this->type];
 		}
-	}
-
-	/**
-	 * Extracts the default value for the column.
-	 * The value is typecasted to correct PHP type.
-	 * @param mixed $defaultValue the default value obtained from metadata
-	 */
-	protected function extractDefault($defaultValue)
-	{
-		$this->defaultValue = $this->typecast($defaultValue);
+		return 'string';
 	}
 
 	/**
@@ -135,17 +109,14 @@ class ColumnSchema extends CComponent
 	 */
 	public function typecast($value)
 	{
-		if (gettype($value) === $this->type || $value === null || $value instanceof CDbExpression)
+		if ($value === null || gettype($value) === $this->phpType || $value instanceof Expression) {
 			return $value;
-		if ($value === '')
-			return $this->type === 'string' ? '' : null;
-		switch ($this->type)
-		{
+		}
+		switch ($this->phpType) {
 			case 'string': return (string)$value;
 			case 'integer': return (integer)$value;
 			case 'boolean': return (boolean)$value;
-			case 'double':
-			default: return $value;
 		}
+		return $value;
 	}
 }
diff --git a/framework/db/dao/QueryBuilder.php b/framework/db/dao/QueryBuilder.php
index 6d97876..c32a429 100644
--- a/framework/db/dao/QueryBuilder.php
+++ b/framework/db/dao/QueryBuilder.php
@@ -151,7 +151,7 @@ class QueryBuilder extends \yii\base\Component
 	public function dropColumn($table, $column)
 	{
 		return "ALTER TABLE " . $this->quoteTableName($table)
-			. " DROP COLUMN " . $this->quoteColumnName($column);
+			. " DROP COLUMN " . $this->quoteSimpleColumnName($column);
 	}
 
 	/**
@@ -165,8 +165,8 @@ class QueryBuilder extends \yii\base\Component
 	public function renameColumn($table, $name, $newName)
 	{
 		return "ALTER TABLE " . $this->quoteTableName($table)
-			. " RENAME COLUMN " . $this->quoteColumnName($name)
-			. " TO " . $this->quoteColumnName($newName);
+			. " RENAME COLUMN " . $this->quoteSimpleColumnName($name)
+			. " TO " . $this->quoteSimpleColumnName($newName);
 	}
 
 	/**
@@ -181,8 +181,8 @@ class QueryBuilder extends \yii\base\Component
 	public function alterColumn($table, $column, $type)
 	{
 		return 'ALTER TABLE ' . $this->quoteTableName($table) . ' CHANGE '
-			. $this->quoteColumnName($column) . ' '
-			. $this->quoteColumnName($column) . ' '
+			. $this->quoteSimpleColumnName($column) . ' '
+			. $this->quoteSimpleColumnName($column) . ' '
 			. $this->getColumnType($type);
 	}
 
diff --git a/framework/db/dao/Schema.php b/framework/db/dao/Schema.php
index 179a1b9..a831a31 100644
--- a/framework/db/dao/Schema.php
+++ b/framework/db/dao/Schema.php
@@ -18,18 +18,18 @@ namespace yii\db\dao;
  */
 abstract class Schema extends \yii\base\Component
 {
+	public $connection;
+
 	private $_tableNames = array();
 	private $_tables = array();
-	private $_connection;
 	private $_builder;
-	private $_cacheExclude = array();
 
 	/**
 	 * Loads the metadata for the specified table.
 	 * @param string $name table name
-	 * @return CDbTableSchema driver dependent table metadata, null if the table does not exist.
+	 * @return TableSchema driver dependent table metadata, null if the table does not exist.
 	 */
-	abstract protected function loadTable($name);
+	abstract protected function loadTableSchema($name);
 
 	/**
 	 * Constructor.
@@ -37,17 +37,7 @@ abstract class Schema extends \yii\base\Component
 	 */
 	public function __construct($connection)
 	{
-		$this->_connection = $connection;
-		foreach ($connection->schemaCachingExclude as $name)
-			$this->_cacheExclude[$name] = true;
-	}
-
-	/**
-	 * @return Connection database connection. The connection is active.
-	 */
-	public function getConnection()
-	{
-		return $this->_connection;
+		$this->connection = $connection;
 	}
 
 	/**
@@ -62,13 +52,13 @@ abstract class Schema extends \yii\base\Component
 		}
 
 		if (strpos($name, '{{') !== false) {
-			$realName = preg_replace('/\{\{(.*?)\}\}/', $this->_connection->tablePrefix . '$1', $name);
+			$realName = preg_replace('/\{\{(.*?)\}\}/', $this->connection->tablePrefix . '$1', $name);
 		}
 		else {
 			$realName = $name;
 		}
-		
-		$db = $this->_connection;
+
+		$db = $this->connection;
 
 		// temporarily disable query caching
 		if ($db->queryCachingDuration >= 0) {
@@ -77,7 +67,7 @@ abstract class Schema extends \yii\base\Component
 		}
 
 		if (!in_array($name, $db->schemaCachingExclude) && $db->schemaCachingDuration >= 0 && ($cache = \Yii::app()->getComponent($db->schemaCacheID)) !== null) {
-			$key = __CLASS__ . ":{$db->dsn}/{$db->username}/{$name}";
+			$key = __CLASS__ . "/{$db->dsn}/{$db->username}/{$name}";
 			if (($table = $cache->get($key)) === false) {
 				$table = $this->loadTableSchema($realName);
 				if ($table !== null) {
@@ -102,15 +92,14 @@ abstract class Schema extends \yii\base\Component
 	 * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
 	 * @return array the metadata for all tables in the database.
 	 * Each array element is an instance of {@link CDbTableSchema} (or its child class).
-	 * The array keys are table names.
 	 */
-	public function getTables($schema = '')
+	public function getTableSchemas($schema = '')
 	{
 		$tables = array();
-		foreach ($this->getTableNames($schema) as $name)
-		{
-			if (($table = $this->getTable($name)) !== null)
-				$tables[$name] = $table;
+		foreach ($this->getTableNames($schema) as $name) {
+			if (($table = $this->getTableSchema($name)) !== null) {
+				$tables[] = $table;
+			}
 		}
 		return $tables;
 	}
@@ -123,20 +112,21 @@ abstract class Schema extends \yii\base\Component
 	 */
 	public function getTableNames($schema = '')
 	{
-		if (!isset($this->_tableNames[$schema]))
+		if (!isset($this->_tableNames[$schema])) {
 			$this->_tableNames[$schema] = $this->findTableNames($schema);
+		}
 		return $this->_tableNames[$schema];
 	}
 
 	/**
-	 * @return CDbCommandBuilder the SQL command builder for this connection.
+	 * @return QueryBuilder the query builder for this connection.
 	 */
-	public function getCommandBuilder()
+	public function getQueryBuilder()
 	{
-		if ($this->_builder !== null)
-			return $this->_builder;
-		else
-			return $this->_builder = $this->createCommandBuilder();
+		if ($this->_builder === null) {
+			$this->_builder = $this->createQueryBuilder();
+		}
+		return $this->_builder;
 	}
 
 	/**
@@ -146,7 +136,7 @@ abstract class Schema extends \yii\base\Component
 	 */
 	public function refresh()
 	{
-		$db = $this->_connection;
+		$db = $this->connection;
 		if ($db->schemaCachingDuration >= 0 && ($cache = \Yii::app()->getComponent($db->schemaCacheID)) !== null) {
 			foreach ($this->_tables as $name => $table) {
 				$key = __CLASS__ . ":{$db->dsn}/{$db->username}/{$name}";
@@ -155,7 +145,6 @@ abstract class Schema extends \yii\base\Component
 		}
 		$this->_tables = array();
 		$this->_tableNames = array();
-		$this->_builder = null;
 	}
 
 	/**
@@ -167,11 +156,13 @@ abstract class Schema extends \yii\base\Component
 	 */
 	public function quoteTableName($name)
 	{
-		if (strpos($name, '.') === false)
+		if (strpos($name, '.') === false) {
 			return $this->quoteSimpleTableName($name);
+		}
 		$parts = explode('.', $name);
-		foreach ($parts as $i => $part)
+		foreach ($parts as $i => $part) {
 			$parts[$i] = $this->quoteSimpleTableName($part);
+		}
 		return implode('.', $parts);
 
 	}
@@ -184,7 +175,7 @@ abstract class Schema extends \yii\base\Component
 	 */
 	public function quoteSimpleTableName($name)
 	{
-		return "'" . $name . "'";
+		return strpos($name, "'") !== false ? $name : "'" . $name . "'";
 	}
 
 	/**
@@ -196,14 +187,13 @@ abstract class Schema extends \yii\base\Component
 	 */
 	public function quoteColumnName($name)
 	{
-		if (($pos = strrpos($name, '.')) !== false)
-		{
+		if (($pos = strrpos($name, '.')) !== false) {
 			$prefix = $this->quoteTableName(substr($name, 0, $pos)) . '.';
 			$name = substr($name, $pos + 1);
 		}
 		else
 			$prefix = '';
-		return $prefix . ($name === '*' ? $name : $this->quoteSimpleColumnName($name));
+		return $prefix . $this->quoteSimpleColumnName($name);
 	}
 
 	/**
@@ -211,45 +201,18 @@ abstract class Schema extends \yii\base\Component
 	 * A simple column name does not contain prefix.
 	 * @param string $name column name
 	 * @return string the properly quoted column name
-	 * @since 1.1.6
 	 */
 	public function quoteSimpleColumnName($name)
 	{
-		return '"' . $name . '"';
-	}
-
-	/**
-	 * Compares two table names.
-	 * The table names can be either quoted or unquoted. This method
-	 * will consider both cases.
-	 * @param string $name1 table name 1
-	 * @param string $name2 table name 2
-	 * @return boolean whether the two table names refer to the same table.
-	 */
-	public function compareTableNames($name1, $name2)
-	{
-		$name1 = str_replace(array('"', '`', "'"), '', $name1);
-		$name2 = str_replace(array('"', '`', "'"), '', $name2);
-		if (($pos = strrpos($name1, '.')) !== false)
-			$name1 = substr($name1, $pos + 1);
-		if (($pos = strrpos($name2, '.')) !== false)
-			$name2 = substr($name2, $pos + 1);
-		if ($this->_connection->tablePrefix !== null)
-		{
-			if (strpos($name1, '{') !== false)
-				$name1 = $this->_connection->tablePrefix . str_replace(array('{', '}'), '', $name1);
-			if (strpos($name2, '{') !== false)
-				$name2 = $this->_connection->tablePrefix . str_replace(array('{', '}'), '', $name2);
-		}
-		return $name1 === $name2;
+		return strpos($name, '"') !== false || $name === '*' ? $name : '"' . $name . '"';
 	}
 
 	/**
-	 * Creates a command builder for the database.
-	 * This method may be overridden by child classes to create a DBMS-specific command builder.
-	 * @return CDbCommandBuilder command builder instance
+	 * 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
 	 */
-	protected function createQueryBuilder()
+	public function createQueryBuilder()
 	{
 		return new QueryBuilder($this);
 	}
diff --git a/framework/db/dao/TableSchema.php b/framework/db/dao/TableSchema.php
index be97032..a7bdae7 100644
--- a/framework/db/dao/TableSchema.php
+++ b/framework/db/dao/TableSchema.php
@@ -39,7 +39,7 @@ class TableSchema extends \yii\base\Component
 	 */
 	public $name;
 	/**
-	 * @var string quoted name of this table. This may include [[schemaName]] if it is not empty.
+	 * @var string quoted name of this table. This will include [[schemaName]] if it is not empty.
 	 */
 	public $quotedName;
 	/**
@@ -51,7 +51,15 @@ class TableSchema extends \yii\base\Component
 	 */
 	public $sequenceName;
 	/**
-	 * @var array foreign keys of this table. The array is indexed by column name. Each value is an array of foreign table name and foreign column name.
+	 * @var array foreign keys of this table. Each array element is of the following structure:
+	 *
+	 * ~~~
+	 * array(
+	 *     'ForeignTableName',
+	 *     'fk1' => 'pk1',  // pk1 is in foreign table
+	 *     'fk2' => 'pk2',  // if composite foreign key
+	 * )
+	 * ~~~
 	 */
 	public $foreignKeys = array();
 	/**
diff --git a/framework/db/dao/mysql/ColumnSchema.php b/framework/db/dao/mysql/ColumnSchema.php
index 671dd12..f9f2b61 100644
--- a/framework/db/dao/mysql/ColumnSchema.php
+++ b/framework/db/dao/mysql/ColumnSchema.php
@@ -8,6 +8,8 @@
  * @license http://www.yiiframework.com/license/
  */
 
+namespace yii\db\dao\mysql;
+
 /**
  * ColumnSchema class describes the column meta data of a MySQL table.
  *
@@ -20,18 +22,76 @@ class ColumnSchema extends \yii\db\dao\ColumnSchema
 	 * Extracts the PHP type from DB type.
 	 * @param string $dbType DB type
 	 */
-	protected function extractType($dbType)
+	public function initTypes($dbType)
 	{
-		if (strncmp($dbType, 'enum', 4) === 0)
-			$this->type = 'string';
-		elseif (strpos($dbType, 'float') !== false || strpos($dbType, 'double') !== false)
-			$this->type = 'double';
-		elseif (strpos($dbType, 'bool') !== false)
-			$this->type = 'boolean';
-		elseif (strpos($dbType, 'int') === 0 && strpos($dbType, 'unsigned') === false || preg_match('/(bit|tinyint|smallint|mediumint)/', $dbType))
-			$this->type = 'integer';
-		else
-			$this->type = 'string';
+		static $typeMap = array(  // dbType => type
+			'tinyint' => 'smallint',
+			'bit' => 'smallint',
+			'smallint' => 'smallint',
+			'mediumint' => 'integer',
+			'int' => 'integer',
+			'integer' => 'integer',
+			'bigint' => 'bigint',
+			'float' => 'float',
+			'double' => 'float',
+			'real' => 'float',
+			'decimal' => 'decimal',
+			'numeric' => 'decimal',
+            'tinytext' => 'text',
+            'mediumtext' => 'text',
+            'longtext' => 'text',
+            'text' => 'text',
+            'varchar' => 'string',
+            'string' => 'string',
+            'char' => 'string',
+			'datetime' => 'datetime',
+			'year' => 'date',
+			'date' => 'date',
+			'time' => 'time',
+			'timestamp' => 'timestamp',
+			'enum' => 'enum',
+		);
+
+		$this->dbType = $dbType;
+		$this->type = 'string';
+		$this->unsigned = strpos($this->dbType, 'unsigned') !== false;
+
+		if (preg_match('/^(\w+)(?:\(([^\)]+)\))?/', $this->dbType, $matches)) {
+			$type = $matches[1];
+			if (isset($typeMap[$type])) {
+				$this->type = $typeMap[$type];
+			}
+
+			if (!empty($matches[2])) {
+				if ($this->type === 'enum') {
+					$values = explode(',', $matches[2]);
+					foreach ($values as $i => $value) {
+						$values[$i] = trim($value, "'");
+					}
+					$this->enumValues = $values;
+				}
+				else {
+					$values = explode(',', $matches[2]);
+					$this->size = $this->precision = (int)$values[0];
+					if (isset($values[1])) {
+						$this->scale = (int)$values[1];
+					}
+					if ($this->size === 1 && ($type === 'tinyint' || $type === 'bit')) {
+						$this->type = 'boolean';
+					}
+					elseif ($type === 'bit') {
+						if ($this->size > 32) {
+							$this->type = 'bigint';
+						}
+						elseif ($this->size === 32) {
+							$this->type = 'integer';
+						}
+					}
+				}
+			}
+		}
+
+		$this->phpType = $this->getPhpType();
 	}
 
 	/**
@@ -39,32 +99,13 @@ class ColumnSchema extends \yii\db\dao\ColumnSchema
 	 * The value is typecasted to correct PHP type.
 	 * @param mixed $defaultValue the default value obtained from metadata
 	 */
-	protected function extractDefault($defaultValue)
+	public function initDefaultValue($defaultValue)
 	{
-		if ($this->dbType === 'timestamp' && $defaultValue === 'CURRENT_TIMESTAMP')
+		if ($this->type === 'timestamp' && $defaultValue === 'CURRENT_TIMESTAMP') {
 			$this->defaultValue = null;
-		else
-			parent::extractDefault($defaultValue);
-	}
-
-	/**
-	 * Extracts size, precision and scale information from column's DB type.
-	 * @param string $dbType the column's DB type
-	 */
-	protected function extractLimit($dbType)
-	{
-		if (strncmp($dbType, 'enum', 4) === 0 && preg_match('/\((.*)\)/', $dbType, $matches))
-		{
-			$values = explode(',', $matches[1]);
-			$size = 0;
-			foreach ($values as $value)
-			{
-				if (($n = strlen($value)) > $size)
-					$size = $n;
-			}
-			$this->size = $this->precision = $size-2;
 		}
-		else
-			parent::extractLimit($dbType);
+		else {
+			$this->defaultValue = $this->typecast($defaultValue);
+		}
 	}
 }
\ No newline at end of file
diff --git a/framework/db/dao/mysql/QueryBuilder.php b/framework/db/dao/mysql/QueryBuilder.php
new file mode 100644
index 0000000..9ec5842
--- /dev/null
+++ b/framework/db/dao/mysql/QueryBuilder.php
@@ -0,0 +1,93 @@
+<?php
+/**
+ * QueryBuilder class file.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2012 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\db\dao\mysql;
+
+/**
+ * QueryBuilder builds a SQL statement based on the specification given as a [[Query]] object.
+ *
+ * @author Qiang Xue <qiang.xue@gmail.com>
+ * @since 2.0
+ */
+class QueryBuilder extends \yii\db\dao\QueryBuilder
+{
+	/**
+	 * @var array the abstract column types mapped to physical column types.
+	 */
+    public $columnTypes = array(
+        'pk' => 'int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY',
+        'string' => 'varchar(255)',
+        'text' => 'text',
+		'smallint' => 'smallint',
+        'integer' => 'int(11)',
+		'bigint'=> 'bigint',
+        'boolean' => 'tinyint(1)',
+        'float' => 'float',
+        'decimal' => 'decimal',
+		'money' => 'decimal(19,4)',
+        'datetime' => 'datetime',
+        'timestamp' => 'timestamp',
+        'time' => 'time',
+        'date' => 'date',
+        'binary' => 'blob',
+    );
+
+	/**
+	 * Builds a SQL statement for renaming a column.
+	 * @param string $table the table whose column is to be renamed. The name will be properly quoted by the method.
+	 * @param string $name the old name of the column. The name will be properly quoted by the method.
+	 * @param string $newName the new name of the column. The name will be properly quoted by the method.
+	 * @return string the SQL statement for renaming a DB column.
+	 * @since 1.1.6
+	 */
+	public function renameColumn($table, $name, $newName)
+	{
+		$db = $this->getDbConnection();
+		$row = $db->createCommand('SHOW CREATE TABLE ' . $db->quoteTableName($table))->queryRow();
+		if ($row === false)
+			throw new CDbException(Yii::t('yii', 'Unable to find "{column}" in table "{table}".', array('{column}' => $name, '{table}' => $table)));
+		if (isset($row['Create Table']))
+			$sql = $row['Create Table'];
+		else
+		{
+			$row = array_values($row);
+			$sql = $row[1];
+		}
+		if (preg_match_all('/^\s*`(.*?)`\s+(.*?),?$/m', $sql, $matches))
+		{
+			foreach ($matches[1] as $i => $c)
+			{
+				if ($c === $name)
+				{
+					return "ALTER TABLE " . $db->quoteTableName($table)
+						. " CHANGE " . $db->quoteColumnName($name)
+						. ' ' . $db->quoteColumnName($newName) . ' ' . $matches[2][$i];
+				}
+			}
+		}
+
+		// try to give back a SQL anyway
+		return "ALTER TABLE " . $db->quoteTableName($table)
+			. " CHANGE " . $db->quoteColumnName($name) . ' ' . $newName;
+	}
+
+	/**
+	 * Builds a SQL statement for dropping a foreign key constraint.
+	 * @param string $name the name of the foreign key constraint to be dropped. The name will be properly quoted by the method.
+	 * @param string $table the table whose foreign is to be dropped. The name will be properly quoted by the method.
+	 * @return string the SQL statement for dropping a foreign key constraint.
+	 * @since 1.1.6
+	 */
+	public function dropForeignKey($name, $table)
+	{
+		return 'ALTER TABLE ' . $this->quoteTableName($table)
+			. ' DROP FOREIGN KEY ' . $this->quoteColumnName($name);
+	}
+}
diff --git a/framework/db/dao/mysql/Schema.php b/framework/db/dao/mysql/Schema.php
index 751ca5c..a11ad40 100644
--- a/framework/db/dao/mysql/Schema.php
+++ b/framework/db/dao/mysql/Schema.php
@@ -1,53 +1,32 @@
 <?php
 /**
- * CMysqlSchema class file.
+ * Schema class file.
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @link http://www.yiiframework.com/
- * @copyright Copyright &copy; 2008-2011 Yii Software LLC
+ * @copyright Copyright &copy; 2008-2012 Yii Software LLC
  * @license http://www.yiiframework.com/license/
  */
 
+namespace yii\db\dao\mysql;
+
 /**
- * CMysqlSchema is the class for retrieving metadata information from a MySQL database (version 4.1.x and 5.x).
+ * Schema is the class for retrieving metadata information from a MySQL database (version 4.1.x and 5.x).
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
- * @version $Id: CMysqlSchema.php 3304 2011-06-23 14:53:50Z qiang.xue $
- * @package system.db.schema.mysql
- * @since 1.0
+ * @since 2.0
  */
-class CMysqlSchema extends CDbSchema
+class Schema extends \yii\db\dao\Schema
 {
 	/**
-	 * @var array the abstract column types mapped to physical column types.
-	 * @since 1.1.6
-	 */
-    public $columnTypes = array(
-        'pk' => 'int(11) NOT NULL AUTO_INCREMENT PRIMARY KEY',
-        'string' => 'varchar(255)',
-        'text' => 'text',
-        'integer' => 'int(11)',
-        'float' => 'float',
-        'decimal' => 'decimal',
-        'datetime' => 'datetime',
-        'timestamp' => 'timestamp',
-        'time' => 'time',
-        'date' => 'date',
-        'binary' => 'blob',
-        'boolean' => 'tinyint(1)',
-		'money' => 'decimal(19,4)',
-    );
-
-	/**
 	 * Quotes a table name for use in a query.
 	 * A simple table name does not schema prefix.
 	 * @param string $name table name
 	 * @return string the properly quoted table name
-	 * @since 1.1.6
 	 */
 	public function quoteSimpleTableName($name)
 	{
-		return '`' . $name . '`';
+		return strpos($name, "`") !== false ? $name : "`" . $name . "`";
 	}
 
 	/**
@@ -55,75 +34,26 @@ class CMysqlSchema extends CDbSchema
 	 * A simple column name does not contain prefix.
 	 * @param string $name column name
 	 * @return string the properly quoted column name
-	 * @since 1.1.6
 	 */
 	public function quoteSimpleColumnName($name)
 	{
-		return '`' . $name . '`';
-	}
-
-	/**
-	 * Compares two table names.
-	 * The table names can be either quoted or unquoted. This method
-	 * will consider both cases.
-	 * @param string $name1 table name 1
-	 * @param string $name2 table name 2
-	 * @return boolean whether the two table names refer to the same table.
-	 */
-	public function compareTableNames($name1, $name2)
-	{
-		return parent::compareTableNames(strtolower($name1), strtolower($name2));
-	}
-
-	/**
-	 * Resets the sequence value of a table's primary key.
-	 * The sequence will be reset such that the primary key of the next new row inserted
-	 * will have the specified value or 1.
-	 * @param CDbTableSchema $table the table schema whose primary key sequence will be reset
-	 * @param mixed $value the value for the primary key of the next new row inserted. If this is not set,
-	 * the next new row's primary key will have a value 1.
-	 * @since 1.1
-	 */
-	public function resetSequence($table, $value = null)
-	{
-		if ($table->sequenceName !== null)
-		{
-			if ($value === null)
-				$value = $this->getDbConnection()->createCommand("SELECT MAX(` {$table->primaryKey}`) FROM  {$table->rawName}")->queryScalar() + 1;
-			else
-				$value = (int)$value;
-			$this->getDbConnection()->createCommand("ALTER TABLE  {$table->rawName} AUTO_INCREMENT=$value")->execute();
-		}
-	}
-
-	/**
-	 * Enables or disables integrity check.
-	 * @param boolean $check whether to turn on or off the integrity check.
-	 * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
-	 * @since 1.1
-	 */
-	public function checkIntegrity($check = true, $schema = '')
-	{
-		$this->getDbConnection()->createCommand('SET FOREIGN_KEY_CHECKS=' . ($check ? 1 : 0))->execute();
+		return strpos($name, '`') !== false || $name === '*' ? $name : '`' . $name . '`';
 	}
 
 	/**
 	 * Loads the metadata for the specified table.
 	 * @param string $name table name
-	 * @return CMysqlTableSchema driver dependent table metadata. Null if the table does not exist.
+	 * @return TableSchema driver dependent table metadata. Null if the table does not exist.
 	 */
-	protected function loadTable($name)
+	protected function loadTableSchema($name)
 	{
-		$table = new CMysqlTableSchema;
+		$table = new TableSchema;
 		$this->resolveTableNames($table, $name);
 
-		if ($this->findColumns($table))
-		{
+		if ($this->findColumns($table)) {
 			$this->findConstraints($table);
 			return $table;
 		}
-		else
-			return null;
 	}
 
 	/**
@@ -134,52 +64,15 @@ class CMysqlSchema extends CDbSchema
 	protected function resolveTableNames($table, $name)
 	{
 		$parts = explode('.', str_replace('`', '', $name));
-		if (isset($parts[1]))
-		{
+		if (isset($parts[1])) {
 			$table->schemaName = $parts[0];
 			$table->name = $parts[1];
-			$table->rawName = $this->quoteTableName($table->schemaName) . '.' . $this->quoteTableName($table->name);
+			$table->quotedName = $this->quoteSimpleTableName($table->schemaName) . '.' . $this->quoteSimpleTableName($table->name);
 		}
-		else
-		{
+		else {
 			$table->name = $parts[0];
-			$table->rawName = $this->quoteTableName($table->name);
-		}
-	}
-
-	/**
-	 * Collects the table column metadata.
-	 * @param CMysqlTableSchema $table the table metadata
-	 * @return boolean whether the table exists in the database
-	 */
-	protected function findColumns($table)
-	{
-		$sql = 'SHOW COLUMNS FROM ' . $table->rawName;
-		try
-		{
-			$columns = $this->getDbConnection()->createCommand($sql)->queryAll();
-		}
-		catch(Exception $e)
-		{
-			return false;
-		}
-		foreach ($columns as $column)
-		{
-			$c = $this->createColumn($column);
-			$table->columns[$c->name] = $c;
-			if ($c->isPrimaryKey)
-			{
-				if ($table->primaryKey === null)
-					$table->primaryKey = $c->name;
-				elseif (is_string($table->primaryKey))
-					$table->primaryKey = array($table->primaryKey, $c->name);
-				else
-					$table->primaryKey[] = $c->name;
-				if ($c->autoIncrement)
-					$table->sequenceName = '';
-			}
+			$table->quotedName = $this->quoteSimpleTableName($table->name);
 		}
-		return true;
 	}
 
 	/**
@@ -189,27 +82,51 @@ class CMysqlSchema extends CDbSchema
 	 */
 	protected function createColumn($column)
 	{
-		$c = new CMysqlColumnSchema;
+		$c = new ColumnSchema;
+
 		$c->name = $column['Field'];
-		$c->rawName = $this->quoteColumnName($c->name);
+		$c->quotedName = $this->quoteSimpleColumnName($c->name);
 		$c->allowNull = $column['Null'] === 'YES';
 		$c->isPrimaryKey = strpos($column['Key'], 'PRI') !== false;
-		$c->isForeignKey = false;
-		$c->init($column['Type'], $column['Default']);
-		$c->autoIncrement = strpos(strtolower($column['Extra']), 'auto_increment') !== false;
+		$c->autoIncrement = stripos($column['Extra'], 'auto_increment') !== false;
+		$c->initTypes($column['Type']);
+		$c->initDefaultValue($column['Default']);
 
 		return $c;
 	}
 
 	/**
-	 * @return float server version.
+	 * Collects the table column metadata.
+	 * @param CMysqlTableSchema $table the table metadata
+	 * @return boolean whether the table exists in the database
 	 */
-	protected function getServerVersion()
+	protected function findColumns($table)
 	{
-		$version = $this->getDbConnection()->getAttribute(PDO::ATTR_SERVER_VERSION);
-		$digits = array();
-		preg_match('/(\d+)\.(\d+)\.(\d+)/', $version, $digits);
-		return floatval($digits[1] . '.' . $digits[2] . $digits[3]);
+		$sql = 'SHOW COLUMNS FROM ' . $table->quotedName;
+		try {
+			$columns = $this->connection->createCommand($sql)->queryAll();
+		}
+		catch(\Exception $e) {
+			return false;
+		}
+		foreach ($columns as $column) {
+			$table->columns[$c->name] = $c = $this->createColumn($column);
+			if ($c->isPrimaryKey) {
+				if ($table->primaryKey === null) {
+					$table->primaryKey = $c->name;
+				}
+				elseif (is_string($table->primaryKey)) {
+					$table->primaryKey = array($table->primaryKey, $c->name);
+				}
+				else {
+					$table->primaryKey[] = $c->name;
+				}
+				if ($c->autoIncrement) {
+					$table->sequenceName = '';
+				}
+			}
+		}
+		return true;
 	}
 
 	/**
@@ -218,23 +135,21 @@ class CMysqlSchema extends CDbSchema
 	 */
 	protected function findConstraints($table)
 	{
-		$row = $this->getDbConnection()->createCommand('SHOW CREATE TABLE ' . $table->rawName)->queryRow();
+		$row = $this->connection->createCommand('SHOW CREATE TABLE ' . $table->quotedName)->queryRow();
 		$matches = array();
 		$regexp = '/FOREIGN KEY\s+\(([^\)]+)\)\s+REFERENCES\s+([^\(^\s]+)\s*\(([^\)]+)\)/mi';
-		foreach ($row as $sql)
-		{
-			if (preg_match_all($regexp, $sql, $matches, PREG_SET_ORDER))
+		foreach ($row as $sql) {
+			if (preg_match_all($regexp, $sql, $matches, PREG_SET_ORDER)) {
+				foreach ($matches as $match) {
+					$fks = array_map('trim', explode(',', str_replace('`', '', $match[1])));
+					$pks = array_map('trim', explode(',', str_replace('`', '', $match[3])));
+					$constraint = array(str_replace('`', '', $match[2])),
+					foreach ($fks as $k => $name) {
+						$constraint[$name] = $pks[$k];
+					}
+					$table->foreignKeys[] = $constraint;
+				}
 				break;
-		}
-		foreach ($matches as $match)
-		{
-			$keys = array_map('trim', explode(',', str_replace('`', '', $match[1])));
-			$fks = array_map('trim', explode(',', str_replace('`', '', $match[3])));
-			foreach ($keys as $k => $name)
-			{
-				$table->foreignKeys[$name] = array(str_replace('`', '', $match[2]), $fks[$k]);
-				if (isset($table->columns[$name]))
-					$table->columns[$name]->isForeignKey = true;
 			}
 		}
 	}
@@ -244,67 +159,16 @@ class CMysqlSchema extends CDbSchema
 	 * @param string $schema the schema of the tables. Defaults to empty string, meaning the current or default schema.
 	 * If not empty, the returned table names will be prefixed with the schema name.
 	 * @return array all table names in the database.
-	 * @since 1.0.2
 	 */
 	protected function findTableNames($schema = '')
 	{
-		if ($schema === '')
-			return $this->getDbConnection()->createCommand('SHOW TABLES')->queryColumn();
-		$names = $this->getDbConnection()->createCommand('SHOW TABLES FROM ' . $this->quoteTableName($schema))->queryColumn();
-		foreach ($names as &$name)
-			$name = $schema . '.' . $name;
-		return $names;
-	}
-
-	/**
-	 * Builds a SQL statement for renaming a column.
-	 * @param string $table the table whose column is to be renamed. The name will be properly quoted by the method.
-	 * @param string $name the old name of the column. The name will be properly quoted by the method.
-	 * @param string $newName the new name of the column. The name will be properly quoted by the method.
-	 * @return string the SQL statement for renaming a DB column.
-	 * @since 1.1.6
-	 */
-	public function renameColumn($table, $name, $newName)
-	{
-		$db = $this->getDbConnection();
-		$row = $db->createCommand('SHOW CREATE TABLE ' . $db->quoteTableName($table))->queryRow();
-		if ($row === false)
-			throw new CDbException(Yii::t('yii', 'Unable to find "{column}" in table "{table}".', array('{column}' => $name, '{table}' => $table)));
-		if (isset($row['Create Table']))
-			$sql = $row['Create Table'];
-		else
-		{
-			$row = array_values($row);
-			$sql = $row[1];
+		if ($schema === '') {
+			return $this->connection->createCommand('SHOW TABLES')->queryColumn();
 		}
-		if (preg_match_all('/^\s*`(.*?)`\s+(.*?),?$/m', $sql, $matches))
-		{
-			foreach ($matches[1] as $i => $c)
-			{
-				if ($c === $name)
-				{
-					return "ALTER TABLE " . $db->quoteTableName($table)
-						. " CHANGE " . $db->quoteColumnName($name)
-						. ' ' . $db->quoteColumnName($newName) . ' ' . $matches[2][$i];
-				}
-			}
+		$names = $this->connection->createCommand('SHOW TABLES FROM ' . $this->quoteSimpleTableName($schema))->queryColumn();
+		foreach ($names as &$name) {
+			$name = $schema . '.' . $name;
 		}
-
-		// try to give back a SQL anyway
-		return "ALTER TABLE " . $db->quoteTableName($table)
-			. " CHANGE " . $db->quoteColumnName($name) . ' ' . $newName;
-	}
-
-	/**
-	 * Builds a SQL statement for dropping a foreign key constraint.
-	 * @param string $name the name of the foreign key constraint to be dropped. The name will be properly quoted by the method.
-	 * @param string $table the table whose foreign is to be dropped. The name will be properly quoted by the method.
-	 * @return string the SQL statement for dropping a foreign key constraint.
-	 * @since 1.1.6
-	 */
-	public function dropForeignKey($name, $table)
-	{
-		return 'ALTER TABLE ' . $this->quoteTableName($table)
-			. ' DROP FOREIGN KEY ' . $this->quoteColumnName($name);
+		return $names;
 	}
 }
diff --git a/framework/db/dao/mysql/TableSchema.php b/framework/db/dao/mysql/TableSchema.php
deleted file mode 100644
index 42dcb51..0000000
--- a/framework/db/dao/mysql/TableSchema.php
+++ /dev/null
@@ -1,24 +0,0 @@
-<?php
-/**
- * TableSchema class file.
- *
- * @author Qiang Xue <qiang.xue@gmail.com>
- * @link http://www.yiiframework.com/
- * @copyright Copyright &copy; 2008-2012 Yii Software LLC
- * @license http://www.yiiframework.com/license/
- */
-
-/**
- * TableSchema represents the metadata for a MySQL table.
- *
- * @author Qiang Xue <qiang.xue@gmail.com>
- * @since 2.0
- */
-class TableSchema extends CDbTableSchema
-{
-	/**
-	 * @var string name of the schema (database) that this table belongs to.
-	 * Defaults to null, meaning no schema (or the current database).
-	 */
-	public $schemaName;
-}