Mongodb notes added

gothere · gothere · commit 1b1fd6d33b46 · 2015-01-08T15:53:38.000-05:00
diff --git a/_posts/2015-1-1-MongoDB-Notes.md b/_posts/2015-1-1-MongoDB-Notes.md
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+---
+layout: post
+title: MongoDB最佳实践笔记
+published: true
+categories: [MongoDB, Maizi]
+---
+
+主要还得看官网
+
+1.  安装命令
+•   sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
+•   echo 'deb http://downloads-distro.mongodb.org/repo/ubuntu-upstart dist 10gen' | sudo tee /etc/apt/sources.list.d/mongodb.list
+•   sudo apt-get update
+•   sudo apt-get install -y mongodb-org
+
+Try MongoDB: http://try.mongodb.org
+
+              停止服务： 
+                   sudo service mongod stop
+              启动服务：
+                   sudo service mongod start
+              切换数据库
+                   use  数据库名  
+
+2.  插入命令
+
+插入数据到students collection
+db.students.insert({name: "张三", school: {name: "清华大学", city: "北京"}, age: 19, gpa: 3.97})
+
+db.students.insert({name: "李四", school: {name: "北京大学", city: "北京"}, age: 20, gpa: 3.3})
+
+db.students.insert({name: "王二", school: {name: "交通大学", city: "上海"}, age: 22, gpa: 3.68})
+
+db.students.insert({name: "小牛", school: {name: "哈工大", city: "哈尔滨"}, age: 21, gpa: 3.50})
+
+db.students.insert({name: "小马", school: {name: "交通大学", city: "西安"}, age: 21, gpa: 3.70})
+
+db.students.insert({name: "小朱"})
+
+
+3.  查询命令
+
+值精确匹配的查询
+db.students.find({name: "张三"})
+两个条件（逻辑与）
+db.students.find({"school.name": "交通大学", "school.city": "西安"})
+通过ID
+db.students.find({"_id" : ObjectId("542717c4a47ef7e2347ffbe0")})
+逻辑或
+db.students.find({$or: [{"school.name": "交通大学"}, {"school.city": "北京"}]})
+逻辑与
+db.students.find({$and: [{"school.name": "交通大学"}, {"school.city": "北京"}]})
+大于小于等
+db.students.find({age:{$lte:20}})
+db.students.find({age:{$gte:20}})
+db.students.find({age:{$lt:20}})
+db.students.find({age:{$gt:20}})
+db.students.find({age:{$ne:20}})
+
+关于数据字段存在与否的查询
+db.students.find({school:{$exists:false}})
+
+基于正则表达式的逻辑查询
+db.students.find({name: /^小/})
+db.students.find({name: /.*四/})
+
+
+3.  Update命令
+
+
+
+4.  Bson Document
+Data Model设计参考资料
+http://docs.mongodb.org/manual/data-modeling/
+
+
+6.  内嵌数组查询
+db.students.insert({name: "张三", school: {name: "清华大学", city: "北京"}, courses:[{name:"MongoDB", grade:88, quiz:[9,8,9,10]},{name:"Java", grade:99,quiz:[3,2,1,5]}], age: 19, gpa: 3.97})
+
+db.students.insert({name: "李四", school: {name: "北京大学", city: "北京"}, courses:[{name:"MongoDB", grade:86, quiz:[5,4,3,7]},{name:"Java", grade:92}, {name:"C++", grade:65}], age: 20, gpa: 3.3})
+
+db.students.insert({name: "王二", school: {name: "交通大学", city: "上海"}, age: 22, gpa: 3.68})
+
+db.students.insert({name: "小牛", school: {name: "哈工大", city: "哈尔滨"}, courses:[{name:"Java", grade:81}, {name:"C++", grade:99}], age: 21, gpa: 3.50})
+
+db.students.insert({name: "小马", school: {name: "交通大学", city: "西安"}, courses:[{name:"MongoDB", grade:96, quiz:[5,4,3,7]}], age: 21, gpa: 3.70})
+
+db.students.insert({name: "小朱"})
+
+
+7.  地理位置查询
+db.pois.insert({name:"AAA Store", loc:{type:"Point", coordinates:[70,30]}})
+db.pois.insert({name:"BBB Bank", loc:{type:"Point", coordinates:[69.99,30.01]}})
+db.pois.insert({name:"CCC Park", loc:{type:"Polygon", coordinates:[[[70,30],[71,31],[71,30],[70,30]]]}})
+db.pois.insert({name:"DDD Forest", loc:{type:"Polygon", coordinates:[[[65,68],[67,68],[67,69],[65,68]]]}})
+
+附近地点查询
+db.pois.find({loc:{
+  $near: {
+     $geometry: {
+        type: "Point" ,
+        coordinates: [ 70 , 30 ]
+     },
+     $maxDistance: 1000000
+  }
+}})
+
+区域内地点查询
+db.pois.find({loc:{ 
+    $geoWithin:{ 
+        $geometry :{ 
+            type : "Polygon",
+                        coordinates : [[[70,30],[71,31],[71,30],[70,30]]]
+                } 
+    } 
+}})
+
+使用geoNear command
+db.runCommand(
+   {
+     geoNear: "pois",
+     near: { type: "Point", coordinates: [ 70, 30 ] },
+     spherical: true,
+     minDistance: 3000,
+     maxDistance: 7000
+   }
+)
+
+9.  全文搜索
+
+db.text.insert({content:"text performs a text search on the content of the fields indexed with a text index."})
+db.text.insert({content:"When dealing with a small number of documents, it is possible for the full-text-search engine to directly scan the contents of the documents with each query, a strategy called 'serial scanning.' This is what some rudimentary tools, such as grep, do when searching."})
+db.text.insert({content:"Soros enjoys playing mongo."})
+db.text.insert({content:"Why don't you use mongo-db?"})
+
+
+
+
+
+10. 学生成绩Group命令
+db.students.group({
+        key:{age:1},
+        cond: {age:{$exists:true}},
+        reduce:function(cur, result) { result.count += 1; result.total_gpa += cur.gpa; result.ava_gpa = result.total_gpa / result.count;},
+        initial: { count: 0 , total_gpa: 0}
+    })
+
+11. 数据聚合 -- 流水线
+各年龄段平均GPA计算和排序
+
+db.students.aggregate([
+    {$match:{age:{$exists:true}}}, 
+    {$group:{_id:"$age", count: {$sum:1}, total_gpa:{$sum:"$gpa"}}},
+    {$project: {_id:1, ava_gpa:{$divide: ["$total_gpa", "$count"]}}},
+    {$sort:{ava_gpa:1}}
+    ])
+
+选课数量统计
+db.students.aggregate(
+    [
+        {$match: {age:{$exists:true},courses:{$exists:true}}},
+        {$project: {age:1, courses_count:{$size:"$courses"}}},
+        {$group: {_id:"$age", acc:{$avg:"$courses_count"}}},
+        {$sort:{acc:-1}}
+    ]
+)
+
+选课不同种类统计
+db.students.aggregate(
+    [
+        {$match: {age:{$exists:true},courses:{$exists:true}}},
+        {$project: {_id:-1, age:1, "courses.name":1}},
+        {$unwind:"$courses"},
+        {$group: {_id:"$age", courses:{$addToSet:"$courses.name"}}},
+        {$project: {_id:1, cc:{$size:"$courses"}}},
+        {$sort: {cc:-1}}
+    ]
+)
+
+
+12 数据聚合MapReduce
+
+按age分组计算平均gpa (错误)
+db.students.mapReduce(
+    function(){
+        emit(this.age, this.gpa);
+    },
+    
+    function(key, values){
+        return Array.sum(values)/values.length;
+    },
+    
+    {
+        query : {age : {$exists : true}, gpa : {$exists : true}},
+        out : {inline:1}
+    }
+)
+
+按age分组计算平均gpa (正确)
+db.students.mapReduce(
+    function(){
+        emit(this.age, {gpa:this.gpa, count:1});
+    },    
+    function(key, values){
+    reducedVal = { gpa: 0, count: 0 };
+        for (var i = 0; i < values.length; i++) {
+            reducedVal.count += values[i].count;
+                reducedVal.gpa += values[i].gpa;
+        }
+        return reducedVal;                  
+    },    
+    {
+        query : {age : {$exists : true}, gpa : {$exists : true}},
+        out : {inline:1},
+    finalize:function(key, value){
+        value.avg = value.gpa / value.count;
+        return value;
+    }   
+    }
+)
+
+课程推荐
+db.students.mapReduce(
+    function(){
+        var course_names = this.courses.map(
+            function(course){
+                return course.name
+            });
+        var intersection_names = course_names.filter(
+            function(c_name){
+                return params.indexOf(c_name) != -1
+            });
+        var diff_names = course_names.filter(
+            function(c_name){
+                return params.indexOf(c_name) == -1
+            });
+        diff_names.forEach(
+            function(c_name){
+                emit(c_name, intersection_names.length / course_names.length)
+            });
+    },    
+    function(key, values){
+    var total = values.reduce(function(p, c) {
+            return p + c;
+        });
+
+        return total;                   
+    },    
+    {
+        query : {courses : {$exists : true}},
+        out : {inline:1},
+    scope: {params: ["MongoDB"]}    
+    }
+)
+
+推荐课程（使用Pipeline）
+db.students.aggregate([
+    {$project:{"c_names":{$map:{input: "$courses", as:"course", in:"$$course.name"}}}},
+    {$project:{c_names:1, 
+        intersection_names:{$setIntersection:[["MongoDB"], "$c_names"]},
+        diff_names:{$setDifference:["$c_names", ["MongoDB"]]}
+        }},
+    {$unwind:"$diff_names"},
+    {$project:{diff_names:1, score: {$divide:[{$size: "$intersection_names"}, {$size:"$c_names"}]}}},
+    {$group: {_id:"$diff_names", score: {$sum: "$score"}}}
+    
+])
+
+
