Mongodb新增的聚合方法及其Java客户端
来源:互联网 发布:光脚马拉松知乎 编辑:程序博客网 时间:2024/05/28 16:25
Aggregation Framework Reference¶
Java Driver and Aggregation Framework¶
Let’s use a simple example to demonstrate how the aggregation helper works. Suppose I am using MongoDB to store my employee’s travel expenses. I’ve created a collection named
I am auditing three departments: Sales, Engineering and Human Resources. I want to calculate each department’s average spend on airfare. I’d like to use the Aggregation Framework for the audit, so I think of the operation in terms of a pipeline:
- Operation: Match documents where
type = "airfare"; then pipe into - Operation: Pass only the
department and the amount fields through the pipeline; then pipe into - Operation: Average the expense
amount, grouped by department.
I will use the aggregation operators
First operation:
Piped into:
Piped into:
Let’s take a look at the results of my audit:
- Mongodb新增的聚合方法及其Java客户端
- Mongodb新增的聚合方法及其Java客户端
- Mongodb新增的聚合方法及其Java客户端
- java对MongoDB的聚合操作(BasicDBObject)
- 学习MongoDB 九: MongoDB聚合(单一用途的聚合方法)(一)
- mongodb的java客户端操作
- MongoDb的Java客户端配置
- MongoDb的Java客户端配置
- hive 新增的聚合功能
- MongoDB的聚合查询
- MongoDB的聚合框架
- mongodb的聚合使用
- MongoDB的聚合操作
- MongoDB的聚合(aggregate)
- mongodb的聚合函数aggregate的$match和$group方法。
- mongodb的聚合函数的$project方法运用。
- mongodb的聚合函数的$group方法运用。
- mongodb的聚合函数的$redact方法运用。
- LeetCode122——Best Time to Buy and Sell Stock II
- 程序员如何做到『编程速度又快,Bug 数量又少』?
- 海量数据处理面试题
- 轻松访问多种类型数据库,database.xml文件的配置方法
- pylearn2安装及测试
- Mongodb新增的聚合方法及其Java客户端
- 黑马程序员——Objective--C笔记之协议
- Lecture 1-5ML and Other Fields
- 弹出层,随意拖拽的网页弹出框JS特效
- jquery学习之自定义动画
- Gradle – Spring 4 MVC Hello World Example
- 1. 编程珠玑笔记一开篇
- 网卡故障:弹出界面eth0: 错误:没有找到合适的设备:没有找到可用于链接System eth0 的设备
- Pylearn2环境配置