其他子model类可继承此类，例如：class Admin_mdl extends MY_Model
此继承类需放在application/core下

子类继承，即可使用父类中方法

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Admin_mdl extends MY_Model {

    const TBL_DB = 'admin_info';

    public function __construct()
    {
        parent::__construct(self::TBL_DB);
    }

}

MY_Model.php文件内容如下：

/**
* MY_Model Class ，create by luguoli
*/
<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class MY_Model extends CI_Model {

    var $TableName = '';

    public function __construct($TableName = '')
    {
        parent::__construct();
        $this->TableName = $TableName;
        log_message('debug', $this->TableName." Model Class Initialized");
    }
    
    public function get_data_by_id($id, $type='id')
    {
        $data = array();

        $this->db->select('*')->from($this->TableName)->where($type, $id)->limit(1);
        $query = $this->db->get();
        if($query->num_rows() == 1)
        {
            $data = $query->row_array();
        }
        $query->free_result();
        
        return $data;
    }


    public function get_datas($limit=NULL, $offset=NULL, $sort=NULL, $select=NULL, $where=NULL)
    {
        //limit
        if($limit && is_numeric($limit))
        {
            $this->db->limit(intval($limit));
        }
        
        //offset
        if($offset && is_numeric($offset))
        {
            $this->db->offset(intval($offset));
        }

        //sort,可多个字段排序，写法：id asc,openid desc
        if($sort && !empty($sort))
        {
            $this->db->order_by($sort);
        }
        else
        {
            $this->db->order_by("id","desc");
        }

        //where,条件，写法：$where = array('name =' => $name, 'id <' => $id);
        if($where && !empty($where))
        {
            $this->db->where($where);
        }

        //select,查询字段，写法：$select = "id,nickname,date";
        if($select && !empty($select))
        {
            $this->db->select($select);
        }

        return $this->db->get($this->TableName);
    }


    public function get_datas_count($where=NULL)
    {
        $data = array();

        if($where && !empty($where))
        {
            $this->db->where($where);
        }

        $this->db->select('count(*) as count')->from($this->TableName);
        $query = $this->db->get();
        if($query->num_rows() == 1)
        {
            $data = $query->row_array();
        }
        $query->free_result();

        return $data;
    }

    
    public function remove_data($id, $type='id')
    {
        $this->db->delete($this->TableName, array($type => $id));
        
        return ($this->db->affected_rows() > 0) ? TRUE : FALSE;
    }
    
    public function add_data($data)
    {       
        $this->db->insert($this->TableName, $data);
        
        return ($this->db->affected_rows() > 0) ? $this->db->insert_id() : FALSE;
    }

    public function update_data($id, $data, $type='id')
    {

        $this->db->where($type, $id);
        $this->db->update($this->TableName, $data);
        
        return ($this->db->affected_rows() > 0) ? TRUE : FALSE;
    }

}

/* End of file MY_Model.php */