thinkphp中的select方法与find方法区别

1. find方法源码，发现find方法只会返回一条记录，有Limit 限制，并且是一维数组，

2. /**
        * 查询数据
        * @access public
        * @param mixed $options 表达式参数
        * @return mixed
        */
       public function find($options=array()) {
           if(is_numeric($options) || is_string($options)) {
               $where[$this->getPk()]  =   $options;
               $options                =   array();
               $options['where']       =   $where;
           }
           // 根据复合主键查找记录
           $pk  =  $this->getPk();
           if (is_array($options) && (count($options) > 0) && is_array($pk)) {
               // 根据复合主键查询
               $count = 0;
               foreach (array_keys($options) as $key) {
                   if (is_int($key)) $count++; 
               } 
               if ($count == count($pk)) {
                   $i = 0;
                   foreach ($pk as $field) {
                       $where[$field] = $options[$i];
                       unset($options[$i++]);
                   }
                   $options['where']  =  $where;
               } else {
                   return false;
               }
           }
           // 老是查找一条记录
           $options['limit']   =   1;
           // 分析表达式
           $options            =   $this->_parseOptions($options);
           // 判断查询缓存
           if(isset($options['cache'])){
               $cache  =   $options['cache'];
               $key    =   is_string($cache['key'])?$cache['key']:md5(serialize($options));
               $data   =   S($key,'',$cache);
               if(false !== $data){
                   $this->data     =   $data;
                   return $data;
               }
           }
           $resultSet          =   $this->db->select($options);
           if(false === $resultSet) {
               return false;
           }
           if(empty($resultSet)) {// 查询结果为空
               return null;
           }
           if(is_string($resultSet)){
               return $resultSet;
           }
   
           // 读取数据后的处理
           $data   =   $this->_read_data($resultSet[0]);
           $this->_after_find($data,$options);
           if(!empty($this->options['result'])) {
               return $this->returnResult($data,$this->options['result']);
           }
           $this->data     =   $data;
           if(isset($cache)){
               S($key,$data,$cache);
           }
           return $this->data;
       }

3. select方法源码，查询数据集，返回二维数组，配合volist标签使用！

4. /**
        * 查询数据集
        * @access public
        * @param array $options 表达式参数
        * @return mixed
        */
       public function select($options=array()) {
           $pk   =  $this->getPk();
           if(is_string($options) || is_numeric($options)) {
               // 根据主键查询
               if(strpos($options,',')) {
                   $where[$pk]     =  array('IN',$options);
               }else{
                   $where[$pk]     =  $options;
               }
               $options            =  array();
               $options['where']   =  $where;
           }elseif (is_array($options) && (count($options) > 0) && is_array($pk)) {
               // 根据复合主键查询
               $count = 0;
               foreach (array_keys($options) as $key) {
                   if (is_int($key)) $count++; 
               } 
               if ($count == count($pk)) {
                   $i = 0;
                   foreach ($pk as $field) {
                       $where[$field] = $options[$i];
                       unset($options[$i++]);
                   }
                   $options['where']  =  $where;
               } else {
                   return false;
               }
           } elseif(false === $options){ // 用于子查询 不查询只返回SQL
           	$options['fetch_sql'] = true;
           }
           // 分析表达式
           $options    =  $this->_parseOptions($options);
           // 判断查询缓存
           if(isset($options['cache'])){
               $cache  =   $options['cache'];
               $key    =   is_string($cache['key'])?$cache['key']:md5(serialize($options));
               $data   =   S($key,'',$cache);
               if(false !== $data){
                   return $data;
               }
           }        
           $resultSet  = $this->db->select($options);
           if(false === $resultSet) {
               return false;
           }
           if(!empty($resultSet)) { // 有查询结果
               if(is_string($resultSet)){
                   return $resultSet;
               }
   
               $resultSet  =   array_map(array($this,'_read_data'),$resultSet);
               $this->_after_select($resultSet,$options);
               if(isset($options['index'])){ // 对数据集进行索引
                   $index  =   explode(',',$options['index']);
                   foreach ($resultSet as $result){
                       $_key   =  $result[$index[0]];
                       if(isset($index[1]) && isset($result[$index[1]])){
                           $cols[$_key] =  $result[$index[1]];
                       }else{
                           $cols[$_key] =  $result;
                       }
                   }
                   $resultSet  =   $cols;
               }
           }
   
           if(isset($cache)){
               S($key,$resultSet,$cache);
           }
           return $resultSet;
       }

5. 参考资料

6. http://blog.csdn.net/baronyang/article/details/8674673