diff --git a/extensions/sphinx/IndexSchema.php b/extensions/sphinx/IndexSchema.php
new file mode 100644
index 0000000..81ba075
--- /dev/null
+++ b/extensions/sphinx/IndexSchema.php
@@ -0,0 +1,82 @@
+<?php
+/**
+ * @link http://www.yiiframework.com/
+ * @copyright Copyright &copy; 2008-2011 Yii Software LLC
+ * @license http://www.yiiframework.com/license/
+ */
+
+namespace yii\sphinx;
+
+use yii\base\Object;
+use yii\base\InvalidParamException;
+
+/**
+ * IndexSchema represents the metadata of a Sphinx index.
+ *
+ * @property array $columnNames List of column names. This property is read-only.
+ *
+ * @author Paul Klimov <klimov.paul@gmail.com>
+ * @since 2.0
+ */
+class IndexSchema extends Object
+{
+	/**
+	 * @var string name of the schema that this index belongs to.
+	 */
+	public $schemaName;
+	/**
+	 * @var string name of this index.
+	 */
+	public $name;
+	/**
+	 * @var string[] primary keys of this index.
+	 */
+	public $primaryKey = [];
+	/**
+	 * @var ColumnSchema[] column metadata of this index. Each array element is a [[ColumnSchema]] object, indexed by column names.
+	 */
+	public $columns = [];
+
+	/**
+	 * Gets the named column metadata.
+	 * This is a convenient method for retrieving a named column even if it does not exist.
+	 * @param string $name column name
+	 * @return ColumnSchema metadata of the named column. Null if the named column does not exist.
+	 */
+	public function getColumn($name)
+	{
+		return isset($this->columns[$name]) ? $this->columns[$name] : null;
+	}
+
+	/**
+	 * Returns the names of all columns in this table.
+	 * @return array list of column names
+	 */
+	public function getColumnNames()
+	{
+		return array_keys($this->columns);
+	}
+
+	/**
+	 * Manually specifies the primary key for this table.
+	 * @param string|array $keys the primary key (can be composite)
+	 * @throws InvalidParamException if the specified key cannot be found in the table.
+	 */
+	public function fixPrimaryKey($keys)
+	{
+		if (!is_array($keys)) {
+			$keys = [$keys];
+		}
+		$this->primaryKey = $keys;
+		foreach ($this->columns as $column) {
+			$column->isPrimaryKey = false;
+		}
+		foreach ($keys as $key) {
+			if (isset($this->columns[$key])) {
+				$this->columns[$key]->isPrimaryKey = true;
+			} else {
+				throw new InvalidParamException("Primary key '$key' cannot be found in index '{$this->name}'.");
+			}
+		}
+	}
+}
\ No newline at end of file
diff --git a/extensions/sphinx/Schema.php b/extensions/sphinx/Schema.php
index b9a34be..8313ae4 100644
--- a/extensions/sphinx/Schema.php
+++ b/extensions/sphinx/Schema.php
@@ -7,17 +7,48 @@
 
 namespace yii\sphinx;
 
-use yii\db\TableSchema;
+use yii\base\Object;
+use yii\caching\Cache;
+use Yii;
+use yii\caching\GroupDependency;
 
 /**
- * Class Schema
+ * Schema represents the Sphinx schema information.
  *
  * @author Paul Klimov <klimov.paul@gmail.com>
  * @since 2.0
  */
-class Schema extends \yii\db\mysql\Schema
+class Schema extends Object
 {
 	/**
+	 * The followings are the supported abstract column data types.
+	 */
+	const TYPE_PK = 'pk';
+	const TYPE_STRING = 'string';
+	const TYPE_INTEGER = 'integer';
+	const TYPE_BIGINT = 'bigint';
+	const TYPE_FLOAT = 'float';
+	const TYPE_TIMESTAMP = 'timestamp';
+	const TYPE_BOOLEAN = 'boolean';
+
+	/**
+	 * @var Connection the Sphinx connection
+	 */
+	public $db;
+	/**
+	 * @var array list of ALL index names in the Sphinx
+	 */
+	private $_indexNames = [];
+	/**
+	 * @var array list of loaded index metadata (index name => IndexSchema)
+	 */
+	private $_indexes = [];
+	/**
+	 * @var QueryBuilder the query builder for this Sphinx connection
+	 */
+	private $_builder;
+
+	/**
 	 * @var array mapping from physical column types (keys) to abstract column types (values)
 	 */
 	public $typeMap = [
@@ -35,8 +66,200 @@ class Schema extends \yii\db\mysql\Schema
 	];
 
 	/**
-	 * Creates a query builder for the database.
-	 * This method may be overridden by child classes to create a DBMS-specific query builder.
+	 * Loads the metadata for the specified index.
+	 * @param string $name index name
+	 * @return IndexSchema driver dependent index metadata. Null if the index does not exist.
+	 */
+	protected function loadTableSchema($name)
+	{
+		$index = new IndexSchema;
+		$this->resolveIndexNames($index, $name);
+
+		if ($this->findColumns($index)) {
+			return $index;
+		} else {
+			return null;
+		}
+	}
+
+	/**
+	 * Resolves the index name and schema name (if any).
+	 * @param IndexSchema $index the index metadata object
+	 * @param string $name the index name
+	 */
+	protected function resolveIndexNames($index, $name)
+	{
+		$parts = explode('.', str_replace('`', '', $name));
+		if (isset($parts[1])) {
+			$index->schemaName = $parts[0];
+			$index->name = $parts[1];
+		} else {
+			$index->name = $parts[0];
+		}
+	}
+
+	/**
+	 * Obtains the metadata for the named index.
+	 * @param string $name index name. The index name may contain schema name if any. Do not quote the index name.
+	 * @param boolean $refresh whether to reload the index schema even if it is found in the cache.
+	 * @return IndexSchema index metadata. Null if the named index does not exist.
+	 */
+	public function getIndexSchema($name, $refresh = false)
+	{
+		if (isset($this->_indexes[$name]) && !$refresh) {
+			return $this->_indexes[$name];
+		}
+
+		$db = $this->db;
+		$realName = $this->getRawIndexName($name);
+
+		if ($db->enableSchemaCache && !in_array($name, $db->schemaCacheExclude, true)) {
+			/** @var $cache Cache */
+			$cache = is_string($db->schemaCache) ? Yii::$app->getComponent($db->schemaCache) : $db->schemaCache;
+			if ($cache instanceof Cache) {
+				$key = $this->getCacheKey($name);
+				if ($refresh || ($index = $cache->get($key)) === false) {
+					$index = $this->loadTableSchema($realName);
+					if ($index !== null) {
+						$cache->set($key, $index, $db->schemaCacheDuration, new GroupDependency($this->getCacheGroup()));
+					}
+				}
+				return $this->_indexes[$name] = $index;
+			}
+		}
+		return $this->_indexes[$name] = $index = $this->loadTableSchema($realName);
+	}
+
+	/**
+	 * Returns the cache key for the specified index name.
+	 * @param string $name the index name
+	 * @return mixed the cache key
+	 */
+	protected function getCacheKey($name)
+	{
+		return [
+			__CLASS__,
+			$this->db->dsn,
+			$this->db->username,
+			$name,
+		];
+	}
+
+	/**
+	 * Returns the cache group name.
+	 * This allows [[refresh()]] to invalidate all cached index schemas.
+	 * @return string the cache group name
+	 */
+	protected function getCacheGroup()
+	{
+		return md5(serialize([
+			__CLASS__,
+			$this->db->dsn,
+			$this->db->username,
+		]));
+	}
+
+	/**
+	 * Returns the metadata for all indexes in the database.
+	 * @param string $schema the schema of the indexes. Defaults to empty string, meaning the current or default schema name.
+	 * @param boolean $refresh whether to fetch the latest available index schemas. If this is false,
+	 * cached data may be returned if available.
+	 * @return IndexSchema[] the metadata for all indexes in the Sphinx.
+	 * Each array element is an instance of [[IndexSchema]] or its child class.
+	 */
+	public function getTableSchemas($schema = '', $refresh = false)
+	{
+		$indexes = [];
+		foreach ($this->getIndexNames($schema, $refresh) as $name) {
+			if ($schema !== '') {
+				$name = $schema . '.' . $name;
+			}
+			if (($index = $this->getIndexSchema($name, $refresh)) !== null) {
+				$indexes[] = $index;
+			}
+		}
+		return $indexes;
+	}
+
+	/**
+	 * Returns all index names in the database.
+	 * @param string $schema the schema of the indexes. Defaults to empty string, meaning the current or default schema name.
+	 * If not empty, the returned index names will be prefixed with the schema name.
+	 * @param boolean $refresh whether to fetch the latest available index names. If this is false,
+	 * index names fetched previously (if available) will be returned.
+	 * @return string[] all index names in the database.
+	 */
+	public function getIndexNames($schema = '', $refresh = false)
+	{
+		if (!isset($this->_indexNames[$schema]) || $refresh) {
+			$this->_indexNames[$schema] = $this->findIndexNames($schema);
+		}
+		return $this->_indexNames[$schema];
+	}
+
+	/**
+	 * Returns all index names in the database.
+	 * @param string $schema the schema of the indexes. Defaults to empty string, meaning the current or default schema.
+	 * @return array all index names in the database. The names have NO schema name prefix.
+	 */
+	protected function findIndexNames($schema = '')
+	{
+		$sql = 'SHOW TABLES';
+		if ($schema !== '') {
+			$sql .= ' FROM ' . $this->quoteSimpleIndexName($schema);
+		}
+		return $this->db->createCommand($sql)->queryColumn();
+	}
+
+	/**
+	 * @return QueryBuilder the query builder for this connection.
+	 */
+	public function getQueryBuilder()
+	{
+		if ($this->_builder === null) {
+			$this->_builder = $this->createQueryBuilder();
+		}
+		return $this->_builder;
+	}
+
+	/**
+	 * Determines the PDO type for the given PHP data value.
+	 * @param mixed $data the data whose PDO type is to be determined
+	 * @return integer the PDO type
+	 * @see http://www.php.net/manual/en/pdo.constants.php
+	 */
+	public function getPdoType($data)
+	{
+		static $typeMap = [
+			// php type => PDO type
+			'boolean' => \PDO::PARAM_BOOL,
+			'integer' => \PDO::PARAM_INT,
+			'string' => \PDO::PARAM_STR,
+			'resource' => \PDO::PARAM_LOB,
+			'NULL' => \PDO::PARAM_NULL,
+		];
+		$type = gettype($data);
+		return isset($typeMap[$type]) ? $typeMap[$type] : \PDO::PARAM_STR;
+	}
+
+	/**
+	 * Refreshes the schema.
+	 * This method cleans up all cached index schemas so that they can be re-created later
+	 * to reflect the Sphinx schema change.
+	 */
+	public function refresh()
+	{
+		/** @var $cache Cache */
+		$cache = is_string($this->db->schemaCache) ? Yii::$app->getComponent($this->db->schemaCache) : $this->db->schemaCache;
+		if ($this->db->enableSchemaCache && $cache instanceof Cache) {
+			GroupDependency::invalidate($cache, $this->getCacheGroup());
+		}
+		$this->_indexNames = [];
+		$this->_indexes = [];
+	}
+
+	/**
+	 * Creates a query builder for the Sphinx.
 	 * @return QueryBuilder query builder instance
 	 */
 	public function createQueryBuilder()
@@ -45,31 +268,148 @@ class Schema extends \yii\db\mysql\Schema
 	}
 
 	/**
-	 * Loads the metadata for the specified table.
-	 * @param string $name table name
-	 * @return TableSchema driver dependent table metadata. Null if the table does not exist.
+	 * Quotes a string value for use in a query.
+	 * Note that if the parameter is not a string, it will be returned without change.
+	 * @param string $str string to be quoted
+	 * @return string the properly quoted string
+	 * @see http://www.php.net/manual/en/function.PDO-quote.php
 	 */
-	protected function loadTableSchema($name)
+	public function quoteValue($str)
+	{
+		if (!is_string($str)) {
+			return $str;
+		}
+
+		$this->db->open();
+		if (($value = $this->db->pdo->quote($str)) !== false) {
+			return $value;
+		} else { // the driver doesn't support quote (e.g. oci)
+			return "'" . addcslashes(str_replace("'", "''", $str), "\000\n\r\\\032") . "'";
+		}
+	}
+
+	/**
+	 * Quotes a index name for use in a query.
+	 * If the index name contains schema prefix, the prefix will also be properly quoted.
+	 * If the index name is already quoted or contains '(' or '{{',
+	 * then this method will do nothing.
+	 * @param string $name index name
+	 * @return string the properly quoted index name
+	 * @see quoteSimpleTableName
+	 */
+	public function quoteIndexName($name)
+	{
+		if (strpos($name, '(') !== false || strpos($name, '{{') !== false) {
+			return $name;
+		}
+		if (strpos($name, '.') === false) {
+			return $this->quoteSimpleIndexName($name);
+		}
+		$parts = explode('.', $name);
+		foreach ($parts as $i => $part) {
+			$parts[$i] = $this->quoteSimpleIndexName($part);
+		}
+		return implode('.', $parts);
+	}
+
+	/**
+	 * 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 '(', '[[' or '{{',
+	 * 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 = $this->quoteIndexName(substr($name, 0, $pos)) . '.';
+			$name = substr($name, $pos + 1);
+		} else {
+			$prefix = '';
+		}
+		return $prefix . $this->quoteSimpleColumnName($name);
+	}
+
+	/**
+	 * Quotes a index name for use in a query.
+	 * A simple index name has no schema prefix.
+	 * @param string $name index name
+	 * @return string the properly quoted index name
+	 */
+	public function quoteSimpleIndexName($name)
+	{
+		return strpos($name, "`") !== false ? $name : "`" . $name . "`";
+	}
+
+	/**
+	 * Quotes a column name for use in a query.
+	 * A simple column name has no prefix.
+	 * @param string $name column name
+	 * @return string the properly quoted column name
+	 */
+	public function quoteSimpleColumnName($name)
 	{
-		$table = new TableSchema;
-		$this->resolveTableNames($table, $name);
+		return strpos($name, '`') !== false || $name === '*' ? $name : '`' . $name . '`';
+	}
 
-		if ($this->findColumns($table)) {
-			return $table;
+	/**
+	 * Returns the actual name of a given index name.
+	 * This method will strip off curly brackets from the given index name
+	 * and replace the percentage character '%' with [[Connection::indexPrefix]].
+	 * @param string $name the index name to be converted
+	 * @return string the real name of the given index name
+	 */
+	public function getRawIndexName($name)
+	{
+		if (strpos($name, '{{') !== false) {
+			$name = preg_replace('/\\{\\{(.*?)\\}\\}/', '\1', $name);
+			return str_replace('%', $this->db->tablePrefix, $name);
 		} else {
-			return null;
+			return $name;
+		}
+	}
+
+	/**
+	 * Extracts the PHP type from abstract DB type.
+	 * @param ColumnSchema $column the column schema information
+	 * @return string PHP type name
+	 */
+	protected function getColumnPhpType($column)
+	{
+		static $typeMap = [ // abstract type => php type
+			'smallint' => 'integer',
+			'integer' => 'integer',
+			'bigint' => 'integer',
+			'boolean' => 'boolean',
+			'float' => 'double',
+		];
+		if (isset($typeMap[$column->type])) {
+			if ($column->type === 'bigint') {
+				return PHP_INT_SIZE == 8 ? 'integer' : 'string';
+			} elseif ($column->type === 'integer') {
+				return PHP_INT_SIZE == 4 ? 'string' : 'integer';
+			} else {
+				return $typeMap[$column->type];
+			}
+		} else {
+			return 'string';
 		}
 	}
 
 	/**
-	 * Collects the metadata of table columns.
-	 * @param TableSchema $table the table metadata
-	 * @return boolean whether the table exists in the database
+	 * Collects the metadata of index columns.
+	 * @param IndexSchema $index the index metadata
+	 * @return boolean whether the index exists in the database
 	 * @throws \Exception if DB query fails
 	 */
-	protected function findColumns($table)
+	protected function findColumns($index)
 	{
-		$sql = 'DESCRIBE ' . $this->quoteSimpleTableName($table->name);
+		$sql = 'DESCRIBE ' . $this->quoteSimpleIndexName($index->name);
 		try {
 			$columns = $this->db->createCommand($sql)->queryAll();
 		} catch (\Exception $e) {
@@ -82,9 +422,9 @@ class Schema extends \yii\db\mysql\Schema
 		}
 		foreach ($columns as $info) {
 			$column = $this->loadColumnSchema($info);
-			$table->columns[$column->name] = $column;
+			$index->columns[$column->name] = $column;
 			if ($column->isPrimaryKey) {
-				$table->primaryKey[] = $column->name;
+				$index->primaryKey[] = $column->name;
 			}
 		}
 		return true;