* @link http://www.yiiframework.com/ * @copyright Copyright © 2008-2011 Yii Software LLC * @license http://www.yiiframework.com/license/ */ /** * CDbCommand represents an SQL statement to execute against a database. * * It is usually created by calling {@link CDbConnection::createCommand}. * The SQL statement to be executed may be set via {@link setText Text}. * * To execute a non-query SQL (such as insert, delete, update), call * {@link execute}. To execute an SQL statement that returns result data set * (such as SELECT), use {@link query} or its convenient versions {@link queryRow}, * {@link queryColumn}, or {@link queryScalar}. * * If an SQL statement returns results (such as a SELECT SQL), the results * can be accessed via the returned {@link CDbDataReader}. * * CDbCommand 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, CDbCommand 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();
*
*
* @property string $text The SQL statement to be executed.
* @property CDbConnection $connection The connection associated with this command.
* @property PDOStatement $pdoStatement The underlying PDOStatement for this command
* It could be null if the statement is not prepared yet.
* @property string $select The SELECT part (without 'SELECT') in the query.
* @property boolean $distinct A value indicating whether SELECT DISTINCT should be used.
* @property string $from The FROM part (without 'FROM' ) in the query.
* @property string $where The WHERE part (without 'WHERE' ) in the query.
* @property mixed $join The join part in the query. This can be an array representing
* multiple join fragments, or a string representing a single jojin fragment.
* Each join fragment will contain the proper join operator (e.g. LEFT JOIN).
* @property string $group The GROUP BY part (without 'GROUP BY' ) in the query.
* @property string $having The HAVING part (without 'HAVING' ) in the query.
* @property string $order The ORDER BY part (without 'ORDER BY' ) in the query.
* @property string $limit The LIMIT part (without 'LIMIT' ) in the query.
* @property string $offset The OFFSET part (without 'OFFSET' ) in the query.
* @property mixed $union The UNION part (without 'UNION' ) in the query.
* This can be either a string or an array representing multiple union parts.
*
* @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 $mode fetch mode
* @return CDbCommand
* @see http://www.php.net/manual/en/function.PDOStatement-setFetchMode.php
* @since 1.1.7
*/
public function setFetchMode($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 CDbCommand 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 $value the SQL statement to be executed
* @return CDbCommand this command instance
*/
public function setText($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.CDbCommand');
$errorInfo = $e instanceof PDOException ? $e->errorInfo : null;
throw new CDbException(Yii::t('yii','CDbCommand failed to prepare the SQL statement: {error}',
array('{error}'=>$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 $driverOptions the driver-specific options (this is available since version 1.1.6)
* @return CDbCommand the current command being executed
* @see http://www.php.net/manual/en/function.PDOStatement-bindParam.php
*/
public function bindParam($name, &$value, $dataType=null, $length=null, $driverOptions=null)
{
$this->prepare();
if($dataType===null)
$this->_statement->bindParam($name,$value,$this->_connection->getPdoType(gettype($value)));
else if($length===null)
$this->_statement->bindParam($name,$value,$dataType);
else if($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 $dataType SQL data type of the parameter. If null, the type is determined by the PHP type of the value.
* @return CDbCommand the current command being executed
* @see http://www.php.net/manual/en/function.PDOStatement-bindValue.php
*/
public function bindValue($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 $values the values to be bound. This must be given in terms of an associative
* array with array keys being the parameter names, and array values the corresponding parameter values.
* For example, array(':name'=>'John', ':age'=>25).
* @return CDbCommand the current command being executed
* @since 1.1.5
*/
public function bindValues($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 $params input parameters (name=>value) for the SQL execution. This is an alternative
* to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
* them in this way can improve the performance. Note that if you pass parameters in this way,
* you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
* binding methods and the input parameters this way can improve the performance.
* @return integer number of rows affected by the execution.
* @throws CException execution failed
*/
public function execute($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().$par,'system.db.CDbCommand');
try
{
if($this->_connection->enableProfiling)
Yii::beginProfile('system.db.CDbCommand.execute('.$this->getText().')','system.db.CDbCommand.execute');
$this->prepare();
if($params===array())
$this->_statement->execute();
else
$this->_statement->execute($params);
$n=$this->_statement->rowCount();
if($this->_connection->enableProfiling)
Yii::endProfile('system.db.CDbCommand.execute('.$this->getText().')','system.db.CDbCommand.execute');
return $n;
}
catch(Exception $e)
{
if($this->_connection->enableProfiling)
Yii::endProfile('system.db.CDbCommand.execute('.$this->getText().')','system.db.CDbCommand.execute');
$errorInfo = $e instanceof PDOException ? $e->errorInfo : null;
$message = $e->getMessage();
Yii::log(Yii::t('yii','CDbCommand::execute() failed: {error}. The SQL statement executed was: {sql}.',
array('{error}'=>$message, '{sql}'=>$this->getText().$par)),CLogger::LEVEL_ERROR,'system.db.CDbCommand');
if(YII_DEBUG)
$message .= '. The SQL statement executed was: '.$this->getText().$par;
throw new CDbException(Yii::t('yii','CDbCommand failed to execute the SQL statement: {error}',
array('{error}'=>$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 $params input parameters (name=>value) for the SQL execution. This is an alternative
* to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
* them in this way can improve the performance. Note that if you pass parameters in this way,
* you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
* binding methods and the input parameters this way can improve the performance.
* @return CDbDataReader the reader object for fetching the query result
* @throws CException execution failed
*/
public function query($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 $params input parameters (name=>value) for the SQL execution. This is an alternative
* to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
* them in this way can improve the performance. Note that if you pass parameters in this way,
* you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
* binding methods and the input parameters this way can improve the performance.
* @return array all rows of the query result. Each array element is an array representing a row.
* An empty array is returned if the query results in nothing.
* @throws CException execution failed
*/
public function queryAll($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 $params input parameters (name=>value) for the SQL execution. This is an alternative
* to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
* them in this way can improve the performance. Note that if you pass parameters in this way,
* you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
* binding methods and the input parameters this way can improve the performance.
* @return mixed the first row (in terms of an array) of the query result, false if no result.
* @throws CException execution failed
*/
public function queryRow($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 $params input parameters (name=>value) for the SQL execution. This is an alternative
* to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
* them in this way can improve the performance. Note that if you pass parameters in this way,
* you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
* binding methods and the input parameters this way can improve the performance.
* @return mixed the value of the first column in the first row of the query result. False is returned if there is no value.
* @throws CException execution failed
*/
public function queryScalar($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 $params input parameters (name=>value) for the SQL execution. This is an alternative
* to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
* them in this way can improve the performance. Note that if you pass parameters in this way,
* you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
* binding methods and the input parameters this way can improve the performance.
* @return array the first column of the query result. Empty array if no result.
* @throws CException execution failed
*/
public function queryColumn($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 $params input parameters (name=>value) for the SQL execution. This is an alternative
* to {@link bindParam} and {@link bindValue}. If you have multiple input parameters, passing
* them in this way can improve the performance. Note that you pass parameters in this way,
* you cannot bind parameters or values using {@link bindParam} or {@link bindValue}, and vice versa.
* binding methods and the input parameters this way can improve the performance.
* @return mixed the method execution result
*/
private function queryInternal($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().$par,'system.db.CDbCommand');
if($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.CDbCommand');
return $result;
}
}
try
{
if($this->_connection->enableProfiling)
Yii::beginProfile('system.db.CDbCommand.query('.$this->getText().$par.')','system.db.CDbCommand.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.CDbCommand.query('.$this->getText().$par.')','system.db.CDbCommand.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.CDbCommand.query('.$this->getText().$par.')','system.db.CDbCommand.query');
$errorInfo = $e instanceof PDOException ? $e->errorInfo : null;
$message = $e->getMessage();
Yii::log(Yii::t('yii','CDbCommand::{method}() failed: {error}. The SQL statement executed was: {sql}.',
array('{method}'=>$method, '{error}'=>$message, '{sql}'=>$this->getText().$par)),CLogger::LEVEL_ERROR,'system.db.CDbCommand');
if(YII_DEBUG)
$message .= '. The SQL statement executed was: '.$this->getText().$par;
throw new CDbException(Yii::t('yii','CDbCommand failed to execute the SQL statement: {error}',
array('{error}'=>$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 $option additional option that should be appended to the 'SELECT' keyword. For example,
* in MySQL, the option 'SQL_CALC_FOUND_ROWS' can be used. This parameter is supported since version 1.1.8.
* @return CDbCommand the command object itself
* @since 1.1.6
*/
public function select($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)$column;
else if(strpos($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 $columns the columns to be selected. See {@link select} for more details.
* @return CDbCommand the command object itself
* @since 1.1.6
*/
public function selectDistinct($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 $tables the table(s) to be selected from. This can be either a string (e.g. 'tbl_user')
* or an array (e.g. array('tbl_user', 'tbl_profile')) specifying one or several table names.
* Table names can contain schema prefixes (e.g. 'public.tbl_user') and/or table aliases (e.g. 'tbl_user u').
* The method will automatically quote the table names unless it contains some parenthesis
* (which means the table is given as a sub-query or DB expression).
* @return CDbCommand the command object itself
* @since 1.1.6
*/
public function from($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.