* @link http://www.yiiframework.com/ * @copyright Copyright © 2008-2012 Yii Software LLC * @license http://www.yiiframework.com/license/ */ namespace yii\db\dao; /** * Command represents a SQL statement to be executed against a database. * * A command object is usually created by calling [[Connection::createCommand]]. * The SQL statement it represents can be set via the [[text]] property. * * To execute a non-query SQL (such as insert, delete, update), call [[execute]]. * To execute an SQL statement that returns result data set (such as SELECT), * use [[query]], [[queryRow]], [[queryColumn]], or [[queryScalar]]. * * If an SQL statement returns results (such as a SELECT SQL), the results * can be accessed via the returned {@link CDbDataReader}. * * Command supports SQL statment preparation and parameter binding. * Call {@link bindParam} to bind a PHP variable to a parameter in SQL. * Call {@link bindValue} to bind a value to an SQL parameter. * When binding a parameter, the SQL statement is automatically prepared. * You may also call {@link prepare} to explicitly prepare an SQL statement. * * Starting from version 1.1.6, Command can also be used as a query builder * that builds a SQL statement from code fragments. For example, *
 * $user = Yii::app()->db->createCommand()
 *     ->select('username, password')
 *     ->from('tbl_user')
 *     ->where('id=:id', array(':id'=>1))
 *     ->queryRow();
 * 
 *
 * @author Qiang Xue 'SELECT * FROM tbl_user'
	 * or array('select'=>'*', 'from'=>'tbl_user'). They are equivalent
	 * in terms of the final query result.
	 *
	 * When passing the query as an array, the following properties are commonly set:
	 * {@link select}, {@link distinct}, {@link from}, {@link where}, {@link join},
	 * {@link group}, {@link having}, {@link order}, {@link limit}, {@link offset} and
	 * {@link union}. Please refer to the setter of each of these properties for details
	 * about valid property values. This feature has been available since version 1.1.6.
	 *
	 * Since 1.1.7 it is possible to use a specific mode of data fetching by setting
 	 * {@link setFetchMode FetchMode}. See {@link http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php}
 	 * for more details.
	 */
	public function __construct(CDbConnection $connection, $query = null)
	{
		$this->_connection = $connection;
		if (is_array($query))
		{
			foreach ($query as $name => $value)
				$this->$name = $value;
		}
		else
			$this->setText($query);
	}
	/**
	 * Set the statement to null when serializing.
	 * @return array
	 */
	public function __sleep()
	{
		$this->_statement = null;
		return array_keys(get_object_vars($this));
	}
	/**
	 * Set the default fetch mode for this statement
	 * @param mixed $mode fetch mode
	 * @return Command
	 * @see http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php
	 * @since 1.1.7
	 */
	public function setFetchMode($mode)
	{
		$params = func_get_args();
		$this->_fetchMode = $params;
		return $this;
	}
	/**
	 * Cleans up the command and prepares for building a new query.
	 * This method is mainly used when a command object is being reused
	 * multiple times for building different queries.
	 * Calling this method will clean up all internal states of the command object.
	 * @return Command this command instance
	 * @since 1.1.6
	 */
	public function reset()
	{
		$this->_text = null;
		$this->_query = null;
		$this->_statement = null;
		$this->_paramLog = array();
		$this->params = array();
		return $this;
	}
	/**
	 * @return string the SQL statement to be executed
	 */
	public function getText()
	{
		if ($this->_text == '' && !empty($this->_query))
			$this->setText($this->buildQuery($this->_query));
		return $this->_text;
	}
	/**
	 * Specifies the SQL statement to be executed.
	 * Any previous execution will be terminated or cancel.
	 * @param string $value the SQL statement to be executed
	 * @return Command this command instance
	 */
	public function setText($value)
	{
		if ($this->_connection->tablePrefix !== null && $value != '')
			$this->_text = preg_replace('/{{(.*?)}}/', $this->_connection->tablePrefix . '\1', $value);
		else
			$this->_text = $value;
		$this->cancel();
		return $this;
	}
	/**
	 * @return CDbConnection the connection associated with this command
	 */
	public function getConnection()
	{
		return $this->_connection;
	}
	/**
	 * @return PDOStatement the underlying PDOStatement for this command
	 * It could be null if the statement is not prepared yet.
	 */
	public function getPdoStatement()
	{
		return $this->_statement;
	}
	/**
	 * Prepares the SQL statement to be executed.
	 * For complex SQL statement that is to be executed multiple times,
	 * this may improve performance.
	 * For SQL statement with binding parameters, this method is invoked
	 * automatically.
	 */
	public function prepare()
	{
		if ($this->_statement == null)
		{
			try
			{
				$this->_statement = $this->getConnection()->getPdoInstance()->prepare($this->getText());
				$this->_paramLog = array();
			}
			catch(Exception $e)
			{
				Yii::log('Error in preparing SQL: ' . $this->getText(), CLogger::LEVEL_ERROR, 'system.db.Command');
                $errorInfo = $e instanceof PDOException ? $e->errorInfo : null;
				throw new CDbException(Yii::t('yii', 'Command failed to prepare the SQL statement: {error}',
					array('{error}' => $e->getMessage())), (int)$e->getCode(), $errorInfo);
			}
		}
	}
	/**
	 * Cancels the execution of the SQL statement.
	 */
	public function cancel()
	{
		$this->_statement = null;
	}
	/**
	 * Binds a parameter to the SQL statement to be executed.
	 * @param mixed $name Parameter identifier. For a prepared statement
	 * using named placeholders, this will be a parameter name of
	 * the form :name. For a prepared statement using question mark
	 * placeholders, this will be the 1-indexed position of the parameter.
	 * @param mixed $value Name of the PHP variable to bind to the SQL statement parameter
	 * @param integer $dataType SQL data type of the parameter. If null, the type is determined by the PHP type of the value.
	 * @param integer $length length of the data type
	 * @param mixed $driverOptions the driver-specific options (this is available since version 1.1.6)
	 * @return Command the current command being executed (this is available since version 1.0.8)
	 * @see http://www.php.net/manual/en/function.PDOStatement-bindParam.php
	 */
	public function bindParam($name, &$value, $dataType = null, $length = null, $driverOptions = null)
	{
		$this->prepare();
		if ($dataType === null)
			$this->_statement->bindParam($name, $value, $this->_connection->getPdoType(gettype($value)));
		elseif ($length === null)
			$this->_statement->bindParam($name, $value, $dataType);
		elseif ($driverOptions === null)
			$this->_statement->bindParam($name, $value, $dataType, $length);
		else
			$this->_statement->bindParam($name, $value, $dataType, $length, $driverOptions);
		$this->_paramLog[$name] =& $value;
		return $this;
	}
	/**
	 * Binds a value to a parameter.
	 * @param mixed $name Parameter identifier. For a prepared statement
	 * using named placeholders, this will be a parameter name of
	 * the form :name. For a prepared statement using question mark
	 * placeholders, this will be the 1-indexed position of the parameter.
	 * @param mixed $value The value to bind to the parameter
	 * @param integer $dataType SQL data type of the parameter. If null, the type is determined by the PHP type of the value.
	 * @return Command the current command being executed (this is available since version 1.0.8)
	 * @see http://www.php.net/manual/en/function.PDOStatement-bindValue.php
	 */
	public function bindValue($name, $value, $dataType = null)
	{
		$this->prepare();
		if ($dataType === null)
			$this->_statement->bindValue($name, $value, $this->_connection->getPdoType(gettype($value)));
		else
			$this->_statement->bindValue($name, $value, $dataType);
		$this->_paramLog[$name] = $value;
		return $this;
	}
	/**
	 * Binds a list of values to the corresponding parameters.
	 * This is similar to {@link bindValue} except that it binds multiple values.
	 * Note that the SQL data type of each value is determined by its PHP type.
	 * @param array $values the values to be bound. This must be given in terms of an associative
	 * array with array keys being the parameter names, and array values the corresponding parameter values.
	 * For example, array(':name'=>'John', ':age'=>25).
	 * @return Command the current command being executed
	 * @since 1.1.5
	 */
	public function bindValues($values)
	{
		$this->prepare();
		foreach ($values as $name => $value)
		{
			$this->_statement->bindValue($name, $value, $this->_connection->getPdoType(gettype($value)));
			$this->_paramLog[$name] = $value;
		}
		return $this;
	}
	/**
	 * Executes the SQL statement.
	 * This method is meant only for executing non-query SQL statement.
	 * No result set will be returned.
	 * @param array $params input parameters (name=>value) for the SQL execution. This is an alternative
	 * to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
	 * them in this way can improve the performance. Note that if you pass parameters in this way,
	 * you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
	 * binding methods and  the input parameters this way can improve the performance.
	 * This parameter has been available since version 1.0.10.
	 * @return integer number of rows affected by the execution.
	 * @throws CException execution failed
	 */
	public function execute($params = array())
	{
		if ($this->_connection->enableParamLogging && ($pars = array_merge($this->_paramLog, $params)) !== array())
		{
			$p = array();
			foreach ($pars as $name => $value)
				$p[$name] = $name . '=' . var_export($value, true);
			$par = '. Bound with ' . implode(', ', $p);
		}
		else
			$par = '';
		Yii::trace('Executing SQL: ' . $this->getText() . $par, 'system.db.Command');
		try
		{
			if ($this->_connection->enableProfiling)
				Yii::beginProfile('system.db.Command.execute(' . $this->getText() . ')', 'system.db.Command.execute');
			$this->prepare();
			if ($params === array())
				$this->_statement->execute();
			else
				$this->_statement->execute($params);
			$n = $this->_statement->rowCount();
			if ($this->_connection->enableProfiling)
				Yii::endProfile('system.db.Command.execute(' . $this->getText() . ')', 'system.db.Command.execute');
			return $n;
		}
		catch(Exception $e)
		{
			if ($this->_connection->enableProfiling)
				Yii::endProfile('system.db.Command.execute(' . $this->getText() . ')', 'system.db.Command.execute');
            $errorInfo = $e instanceof PDOException ? $e->errorInfo : null;
            $message = $e->getMessage();
			Yii::log(Yii::t('yii', 'Command::execute() failed: {error}. The SQL statement executed was: {sql}.',
				array('{error}' => $message, '{sql}' => $this->getText() . $par)), CLogger::LEVEL_ERROR, 'system.db.Command');
            if (YII_DEBUG)
            	$message .= '. The SQL statement executed was: ' . $this->getText() . $par;
			throw new CDbException(Yii::t('yii', 'Command failed to execute the SQL statement: {error}',
				array('{error}' => $message)), (int)$e->getCode(), $errorInfo);
		}
	}
	/**
	 * Executes the SQL statement and returns query result.
	 * This method is for executing an SQL query that returns result set.
	 * @param array $params input parameters (name=>value) for the SQL execution. This is an alternative
	 * to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
	 * them in this way can improve the performance. Note that if you pass parameters in this way,
	 * you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
	 * binding methods and  the input parameters this way can improve the performance.
	 * This parameter has been available since version 1.0.10.
	 * @return CDbDataReader the reader object for fetching the query result
	 * @throws CException execution failed
	 */
	public function query($params = array())
	{
		return $this->queryInternal('', 0, $params);
	}
	/**
	 * Executes the SQL statement and returns all rows.
	 * @param boolean $fetchAssociative whether each row should be returned as an associated array with
	 * column names as the keys or the array keys are column indexes (0-based).
	 * @param array $params input parameters (name=>value) for the SQL execution. This is an alternative
	 * to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
	 * them in this way can improve the performance. Note that if you pass parameters in this way,
	 * you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
	 * binding methods and  the input parameters this way can improve the performance.
	 * This parameter has been available since version 1.0.10.
	 * @return array all rows of the query result. Each array element is an array representing a row.
	 * An empty array is returned if the query results in nothing.
	 * @throws CException execution failed
	 */
	public function queryAll($fetchAssociative = true, $params = array())
	{
		return $this->queryInternal('fetchAll', $fetchAssociative ? $this->_fetchMode : PDO::FETCH_NUM, $params);
	}
	/**
	 * Executes the SQL statement and returns the first row of the result.
	 * This is a convenient method of {@link query} when only the first row of data is needed.
	 * @param boolean $fetchAssociative whether the row should be returned as an associated array with
	 * column names as the keys or the array keys are column indexes (0-based).
	 * @param array $params input parameters (name=>value) for the SQL execution. This is an alternative
	 * to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
	 * them in this way can improve the performance. Note that if you pass parameters in this way,
	 * you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
	 * binding methods and  the input parameters this way can improve the performance.
	 * This parameter has been available since version 1.0.10.
	 * @return mixed the first row (in terms of an array) of the query result, false if no result.
	 * @throws CException execution failed
	 */
	public function queryRow($fetchAssociative = true, $params = array())
	{
		return $this->queryInternal('fetch', $fetchAssociative ? $this->_fetchMode : PDO::FETCH_NUM, $params);
	}
	/**
	 * Executes the SQL statement and returns the value of the first column in the first row of data.
	 * This is a convenient method of {@link query} when only a single scalar
	 * value is needed (e.g. obtaining the count of the records).
	 * @param array $params input parameters (name=>value) for the SQL execution. This is an alternative
	 * to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
	 * them in this way can improve the performance. Note that if you pass parameters in this way,
	 * you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
	 * binding methods and  the input parameters this way can improve the performance.
	 * This parameter has been available since version 1.0.10.
	 * @return mixed the value of the first column in the first row of the query result. False is returned if there is no value.
	 * @throws CException execution failed
	 */
	public function queryScalar($params = array())
	{
		$result = $this->queryInternal('fetchColumn', 0, $params);
		if (is_resource($result) && get_resource_type($result) === 'stream')
			return stream_get_contents($result);
		else
			return $result;
	}
	/**
	 * Executes the SQL statement and returns the first column of the result.
	 * This is a convenient method of {@link query} when only the first column of data is needed.
	 * Note, the column returned will contain the first element in each row of result.
	 * @param array $params input parameters (name=>value) for the SQL execution. This is an alternative
	 * to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
	 * them in this way can improve the performance. Note that if you pass parameters in this way,
	 * you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
	 * binding methods and  the input parameters this way can improve the performance.
	 * This parameter has been available since version 1.0.10.
	 * @return array the first column of the query result. Empty array if no result.
	 * @throws CException execution failed
	 */
	public function queryColumn($params = array())
	{
		return $this->queryInternal('fetchAll', PDO::FETCH_COLUMN, $params);
	}
	/**
	 * @param string $method method of PDOStatement to be called
	 * @param mixed $mode parameters to be passed to the method
	 * @param array $params input parameters (name=>value) for the SQL execution. This is an alternative
	 * to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
	 * them in this way can improve the performance. Note that you pass parameters in this way,
	 * you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
	 * binding methods and  the input parameters this way can improve the performance.
	 * This parameter has been available since version 1.0.10.
	 * @return mixed the method execution result
	 */
	private function queryInternal($method, $mode, $params = array())
	{
		$params = array_merge($this->params, $params);
		if ($this->_connection->enableParamLogging && ($pars = array_merge($this->_paramLog, $params)) !== array())
		{
			$p = array();
			foreach ($pars as $name => $value)
				$p[$name] = $name . '=' . var_export($value, true);
			$par = '. Bound with ' . implode(', ', $p);
		}
		else
			$par = '';
		Yii::trace('Querying SQL: ' . $this->getText() . $par, 'system.db.Command');
		if ($this->_connection->queryCachingCount > 0 && $method !== ''
				&& $this->_connection->queryCachingDuration > 0
				&& $this->_connection->queryCacheID !== false
				&& ($cache = Yii::app()->getComponent($this->_connection->queryCacheID)) !== null)
		{
			$this->_connection->queryCachingCount--;
			$cacheKey = 'yii:dbquery' . $this->_connection->connectionString . ':' . $this->_connection->username;
			$cacheKey .= ':' . $this->getText() . ':' . serialize(array_merge($this->_paramLog, $params));
			if (($result = $cache->get($cacheKey)) !== false)
			{
				Yii::trace('Query result found in cache', 'system.db.Command');
				return $result;
			}
		}
		try
		{
			if ($this->_connection->enableProfiling)
				Yii::beginProfile('system.db.Command.query(' . $this->getText() . $par . ')', 'system.db.Command.query');
			$this->prepare();
			if ($params === array())
				$this->_statement->execute();
			else
				$this->_statement->execute($params);
			if ($method === '')
				$result = new CDbDataReader($this);
			else
			{
				$mode = (array)$mode;
				$result = call_user_func_array(array($this->_statement, $method), $mode);
				$this->_statement->closeCursor();
			}
			if ($this->_connection->enableProfiling)
				Yii::endProfile('system.db.Command.query(' . $this->getText() . $par . ')', 'system.db.Command.query');
			if (isset($cache, $cacheKey))
				$cache->set($cacheKey, $result, $this->_connection->queryCachingDuration, $this->_connection->queryCachingDependency);
			return $result;
		}
		catch(Exception $e)
		{
			if ($this->_connection->enableProfiling)
				Yii::endProfile('system.db.Command.query(' . $this->getText() . $par . ')', 'system.db.Command.query');
            $errorInfo = $e instanceof PDOException ? $e->errorInfo : null;
            $message = $e->getMessage();
			Yii::log(Yii::t('yii', 'Command::{method}() failed: {error}. The SQL statement executed was: {sql}.',
				array('{method}' => $method, '{error}' => $message, '{sql}' => $this->getText() . $par)), CLogger::LEVEL_ERROR, 'system.db.Command');
            if (YII_DEBUG)
            	$message .= '. The SQL statement executed was: ' . $this->getText() . $par;
			throw new CDbException(Yii::t('yii', 'Command failed to execute the SQL statement: {error}',
				array('{error}' => $message)), (int)$e->getCode(), $errorInfo);
		}
	}
	/**
	 * Builds a SQL SELECT statement from the given query specification.
	 * @param array $query the query specification in name-value pairs. The following
	 * query options are supported: {@link select}, {@link distinct}, {@link from},
	 * {@link where}, {@link join}, {@link group}, {@link having}, {@link order},
	 * {@link limit}, {@link offset} and {@link union}.
	 * @return string the SQL statement
	 * @since 1.1.6
	 */
	public function buildQuery($query)
	{
		$sql = isset($query['distinct']) && $query['distinct'] ? 'SELECT DISTINCT' : 'SELECT';
		$sql .= ' ' . (isset($query['select']) ? $query['select'] : '*');
		if (isset($query['from']))
			$sql .= "\nFROM " . $query['from'];
		else
			throw new CDbException(Yii::t('yii', 'The DB query must contain the "from" portion.'));
		if (isset($query['join']))
			$sql .= "\n" . (is_array($query['join']) ? implode("\n", $query['join']) : $query['join']);
		if (isset($query['where']))
			$sql .= "\nWHERE " . $query['where'];
		if (isset($query['group']))
			$sql .= "\nGROUP BY " . $query['group'];
		if (isset($query['having']))
			$sql .= "\nHAVING " . $query['having'];
		if (isset($query['order']))
			$sql .= "\nORDER BY " . $query['order'];
		$limit = isset($query['limit']) ? (int)$query['limit'] : -1;
		$offset = isset($query['offset']) ? (int)$query['offset'] : -1;
		if ($limit >= 0 || $offset > 0)
			$sql = $this->_connection->getCommandBuilder()->applyLimit($sql, $limit, $offset);
		if (isset($query['union']))
			$sql .= "\nUNION (\n" . (is_array($query['union']) ? implode("\n) UNION (\n", $query['union']) : $query['union']) . ')';
		return $sql;
	}
	/**
	 * Sets the SELECT part of the query.
	 * @param mixed $columns the columns to be selected. Defaults to '*', meaning all columns.
	 * Columns can be specified in either a string (e.g. "id, name") or an array (e.g. array('id', 'name')).
	 * Columns can contain table prefixes (e.g. "tbl_user.id") and/or column aliases (e.g. "tbl_user.id AS user_id").
	 * The method will automatically quote the column names unless a column contains some parenthesis
	 * (which means the column contains a DB expression).
	 * @param string $option additional option that should be appended to the 'SELECT' keyword. For example,
	 * in MySQL, the option 'SQL_CALC_FOUND_ROWS' can be used. This parameter is supported since version 1.1.8.
	 * @return Command the command object itself
	 * @since 1.1.6
	 */
	public function select($columns = '*', $option = '')
	{
		if (is_string($columns) && strpos($columns, '(') !== false)
			$this->_query['select'] = $columns;
		else
		{
			if (!is_array($columns))
				$columns = preg_split('/\s*,\s*/', trim($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+)(.*)$/', $column, $matches))
						$columns[$i] = $this->_connection->quoteColumnName($matches[1]) . ' AS ' . $this->_connection->quoteColumnName($matches[2]);
					else
						$columns[$i] = $this->_connection->quoteColumnName($column);
				}
			}
			$this->_query['select'] = implode(', ', $columns);
		}
		if ($option != '')
			$this->_query['select'] = $option . ' ' . $this->_query['select'];
		return $this;
	}
	/**
	 * Returns the SELECT part in the query.
	 * @return string the SELECT part (without 'SELECT') in the query.
	 * @since 1.1.6
	 */
	public function getSelect()
	{
		return isset($this->_query['select']) ? $this->_query['select'] : '';
	}
	/**
	 * Sets the SELECT part in the query.
	 * @param mixed $value the data to be selected. Please refer to {@link select()} for details
	 * on how to specify this parameter.
	 * @since 1.1.6
	 */
	public function setSelect($value)
	{
		$this->select($value);
	}
	/**
	 * Sets the SELECT part of the query with the DISTINCT flag turned on.
	 * This is the same as {@link select} except that the DISTINCT flag is turned on.
	 * @param mixed $columns the columns to be selected. See {@link select} for more details.
	 * @return Command the command object itself
	 * @since 1.1.6
	 */
	public function selectDistinct($columns = '*')
	{
		$this->_query['distinct'] = true;
		return $this->select($columns);
	}
	/**
	 * Returns a value indicating whether SELECT DISTINCT should be used.
	 * @return boolean a value indicating whether SELECT DISTINCT should be used.
	 * @since 1.1.6
	 */
	public function getDistinct()
	{
		return isset($this->_query['distinct']) ? $this->_query['distinct'] : false;
	}
	/**
	 * Sets a value indicating whether SELECT DISTINCT should be used.
	 * @param boolean $value a value indicating whether SELECT DISTINCT should be used.
	 * @since 1.1.6
	 */
	public function setDistinct($value)
	{
		$this->_query['distinct'] = $value;
	}
	/**
	 * Sets the FROM part of the query.
	 * @param mixed $tables the table(s) to be selected from. This can be either a string (e.g. 'tbl_user')
	 * or an array (e.g. array('tbl_user', 'tbl_profile')) specifying one or several table names.
	 * Table names can contain schema prefixes (e.g. 'public.tbl_user') and/or table aliases (e.g. 'tbl_user u').
	 * The method will automatically quote the table names unless it contains some parenthesis
	 * (which means the table is given as a sub-query or DB expression).
	 * @return Command the command object itself
	 * @since 1.1.6
	 */
	public function from($tables)
	{
		if (is_string($tables) && strpos($tables, '(') !== false)
			$this->_query['from'] = $tables;
		else
		{
			if (!is_array($tables))
				$tables = preg_split('/\s*,\s*/', trim($tables), -1, PREG_SPLIT_NO_EMPTY);
			foreach ($tables as $i => $table)
			{
				if (strpos($table, '(') === false)
				{
					if (preg_match('/^(.*?)(?i:\s+as\s+|\s+)(.*)$/', $table, $matches))  // with alias
						$tables[$i] = $this->_connection->quoteTableName($matches[1]) . ' ' . $this->_connection->quoteTableName($matches[2]);
					else
						$tables[$i] = $this->_connection->quoteTableName($table);
				}
			}
			$this->_query['from'] = implode(', ', $tables);
		}
		return $this;
	}
	/**
	 * Returns the FROM part in the query.
	 * @return string the FROM part (without 'FROM' ) in the query.
	 * @since 1.1.6
	 */
	public function getFrom()
	{
		return isset($this->_query['from']) ? $this->_query['from'] : '';
	}
	/**
	 * Sets the FROM part in the query.
	 * @param mixed $value the tables to be selected from. Please refer to {@link from()} for details
	 * on how to specify this parameter.
	 * @since 1.1.6
	 */
	public function setFrom($value)
	{
		$this->from($value);
	}
	/**
	 * Sets the WHERE part of the query.
	 *
	 * The method requires a $conditions parameter, and optionally a $params parameter
	 * specifying the values to be bound to the query.
	 *
	 * The $conditions parameter should be either a string (e.g. 'id=1') or an array.
	 * If the latter, it must be of the format array(operator, operand1, operand2, ...),
	 * where the operator can be one of the followings, and the possible operands depend on the corresponding
	 * operator:
	 * and: the operands should be concatenated together using AND. For example,
	 * array('and', 'id=1', 'id=2') will generate 'id=1 AND id=2'. If an operand is an array,
	 * it will be converted into a string using the same rules described here. For example,
	 * array('and', 'type=1', array('or', 'id=1', 'id=2')) will generate 'type=1 AND (id=1 OR id=2)'.
	 * The method will NOT do any quoting or escaping.or: similar as the and operator except that the operands are concatenated using OR.in: operand 1 should be a column or DB expression, and operand 2 be an array representing
	 * the range of the values that the column or DB expression should be in. For example,
	 * array('in', 'id', array(1,2,3)) will generate 'id IN (1,2,3)'.
	 * The method will properly quote the column name and escape values in the range.not in: similar as the in operator except that IN is replaced with NOT IN in the generated condition.like: operand 1 should be a column or DB expression, and operand 2 be a string or an array representing
	 * the values that the column or DB expression should be like.
	 * For example, array('like', 'name', '%tester%') will generate "name LIKE '%tester%'".
	 * When the value range is given as an array, multiple LIKE predicates will be generated and concatenated using AND.
	 * For example, array('like', 'name', array('%test%', '%sample%')) will generate
	 * "name LIKE '%test%' AND name LIKE '%sample%'".
	 * The method will properly quote the column name and escape values in the range.not like: similar as the like operator except that LIKE is replaced with NOT LIKE in the generated condition.or like: similar as the like operator except that OR is used to concatenated the LIKE predicates.or not like: similar as the not like operator except that OR is used to concatenated the NOT LIKE predicates.