exports.queryArticle = function(search,pageSize,pageIndex,callback){

    var start_index = pageSize*pageIndex;
    var query = articleModel.find(search).limit(pageSize);  
    if(start_index>0)
    {
        query.skip(start_index);
    }
    query.sort('-create_date');
    query.exec(function (err, list) {
        if(err){
            callback(err);
        }
        else{
            var pagedList = {};
            pagedList.pageIndex = pageIndex;
            pagedList.dataList= list;

            if( pageIndex ==0 ){  //如果是第一页 则需要获取总页面
                articleModel.count(search,function(errcount,count){
                    if(errcount){
                        callback(errcount);
                    }
                    else{
                        pagedList.total = count; 
                        callback(null,pagedList);
                    }
                });
              
            }
            else{
                callback(null,pagedList);
            }            
        }
    });
    
}