mongodb数据库入门

官网地址https://www.mongodb.com/

  • mongo的安装

  1. 点击下载https://www.mongodb.com/download-center/community
  2. 点击exe程序一步一步向下安装直到结束
  3. 配置path环境，找到C:\Program Files\MongoDB\Server\3.4\bin这个目录。电脑属性==》高级==》环境变量==》编辑path==》添加刚刚这个目录到path
  4. 打开cmd,输入mongo,出现以下这些就说明配置成功了

mongodb数据库入门

 

 

  • 数据库的连接与使用

  1. 新建mongo文件夹，复制目录
  2. 开启服务，打开cmd，输入mongod --dbpath F:\2019\node\mongo(你的路径名字)mongodb数据库入门
  3. 管理数据库（ps:另开一个cmd，刚刚那个也不要关）,输入mongo  

        mongodb数据库入门

 

 

  • 数据库的增删改查

  1. 查看所有数据库show dbs 
    > show dbs
admin  0.000GB
local  0.000GB

     

  2. 清屏cls
  3. 使用并创建数据库 use <数据库名字>（ps:use就代表了已经创建这个数据库了） 
    > use school
switched to db school

     

  4. 插入数据  db.<集合名字>.insert({"name":"希望小学1"})   （ps:集合名字自己命名，插入数据之后就会自动创建集合）

    > db.class.insert({"name":"3年级"},{"name":"4年级"})
WriteResult({ "nInserted" : 1 })

     

  5. 显示集合名字 show collections

    > show collections
class
student

     

  6. 查找所有数据  db.<集合名字>.find()

    > db.student.find()
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红", "age" : "1" }
{ "_id" : ObjectId("5c89d9941eae9c63db0e378c"), "name" : "丽丽", "age" : "51" }

     

  7. 按条件查询，举个例子，查询年龄等于12的学生

    > db.student.find({age:"12"})
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }

    举个例子，查询年龄大于22的学生

    > db.student.find({age:{$gt:"22"}})
{ "_id" : ObjectId("5c89d9941eae9c63db0e378c"), "name" : "丽丽", "age" : "51" }
{ "_id" : ObjectId("5c89db3d1eae9c63db0e378e"), "name" : "wangwu", "age" : "32" }
{ "_id" : ObjectId("5c89db461eae9c63db0e378f"), "name" : "wangwu566", "age" : "32" }
{ "_id" : ObjectId("5c89db591eae9c63db0e3790"), "name" : "baby", "age" : "52" }

    举个例子，查询年龄小于22的学生

    > db.student.find({age:{$lt:"22"}})
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红", "age" : "1" }
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }

    举个例子，查询年龄小于等于12的学生

    > db.student.find({age:{$lte:"12"}})
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红", "age" : "1" }
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }

    举个例子，查询年龄大于12小于52的学生

    > db.student.find({age:{$lt:"52",$gt:"12"}})
{ "_id" : ObjectId("5c89d9941eae9c63db0e378c"), "name" : "丽丽", "age" : "51" }
{ "_id" : ObjectId("5c89db3d1eae9c63db0e378e"), "name" : "wangwu", "age" : "32" }
{ "_id" : ObjectId("5c89db461eae9c63db0e378f"), "name" : "wangwu566", "age" : "32" }

    举个例子，查询名字中有wangwu的学生

    > db.student.find({name:/wangwu/})
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }
{ "_id" : ObjectId("5c89db3d1eae9c63db0e378e"), "name" : "wangwu", "age" : "32" }
{ "_id" : ObjectId("5c89db461eae9c63db0e378f"), "name" : "wangwu566", "age" : "32" }

    举个例子，查询名字中以小开头的学生

    > db.student.find({name:/^小/})
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红", "age" : "1" }

    举个例子，查询指定列 name的数据

    > db.student.find({},{name:1})            
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红" }
{ "_id" : ObjectId("5c89d9941eae9c63db0e378c"), "name" : "丽丽" }
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu" }
{ "_id" : ObjectId("5c89db3d1eae9c63db0e378e"), "name" : "wangwu" }
{ "_id" : ObjectId("5c89db461eae9c63db0e378f"), "name" : "wangwu566" }
{ "_id" : ObjectId("5c89db591eae9c63db0e3790"), "name" : "baby" }
{ "_id" : ObjectId("5c89df6f1eae9c63db0e3791"), "name" : "小刚" }

    举个例子，查询按照年龄排序，升序1，降序-1

    > db.student.find().sort({age:1})
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红", "age" : "1" }
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }
{ "_id" : ObjectId("5c89db3d1eae9c63db0e378e"), "name" : "wangwu", "age" : "32" }
{ "_id" : ObjectId("5c89db461eae9c63db0e378f"), "name" : "wangwu566", "age" : "32" }
{ "_id" : ObjectId("5c89d9941eae9c63db0e378c"), "name" : "丽丽", "age" : "51" }
{ "_id" : ObjectId("5c89db591eae9c63db0e3790"), "name" : "baby", "age" : "52" }

    举个例子，查询前3条数据

    > db.student.find().limit(3)
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红", "age" : "1" }
{ "_id" : ObjectId("5c89d9941eae9c63db0e378c"), "name" : "丽丽", "age" : "51" }
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }

    举个例子，查询后3条以后的数据

    > db.student.find().skip(3)
{ "_id" : ObjectId("5c89db3d1eae9c63db0e378e"), "name" : "wangwu", "age" : "32" }
{ "_id" : ObjectId("5c89db461eae9c63db0e378f"), "name" : "wangwu566", "age" : "32" }
{ "_id" : ObjectId("5c89db591eae9c63db0e3790"), "name" : "baby", "age" : "52" }
{ "_id" : ObjectId("5c89df6f1eae9c63db0e3791"), "性别" : "男", "name" : "小刚" }

    举个例子，查询2-5之间的数据

    > db.student.find().limit(3).skip(2)
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }
{ "_id" : ObjectId("5c89db3d1eae9c63db0e378e"), "name" : "wangwu", "age" : "32" }
{ "_id" : ObjectId("5c89db461eae9c63db0e378f"), "name" : "wangwu566", "age" : "32" }

    举个例子，查询年龄为1或者年龄为12的数据

    > db.student.find({$or:[{age:"1"},{age:"12"}]})
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红", "age" : "1" }
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }

    举个例子，查找第一条数据

    > db.student.findOne()
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "name" : "小红", "age" : "1" }

    举个例子，查询某个结果的条数

    > db.student.find().count()
7

     

  8. 修改数据，举个例子，修改名字叫小红的，改成15岁

    > db.student.update({"name":"小红"},{$set:{"age":"15"}})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })

    如果想要完整替换，就不要出现关键字$set

    > db.student.update({"name":"小红"},{"age":"15"})
WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
> db.student.find()                              })
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "age" : "15" }
{ "_id" : ObjectId("5c89d9941eae9c63db0e378c"), "name" : "丽丽", "age" : "51" }
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }

     

  9. 删除数据db.collectionsNames.remove( {} )

    > db.student.remove({"age":"32"})
WriteResult({ "nRemoved" : 2 })
> db.student.find()
{ "_id" : ObjectId("5c89d9791eae9c63db0e378b"), "age" : "15" }
{ "_id" : ObjectId("5c89d9941eae9c63db0e378c"), "name" : "丽丽", "age" : "51" }
{ "_id" : ObjectId("5c89db361eae9c63db0e378d"), "name" : "wangwu", "age" : "12" }
{ "_id" : ObjectId("5c89db591eae9c63db0e3790"), "name" : "baby", "age" : "52" }
{ "_id" : ObjectId("5c89df6f1eae9c63db0e3791"), "性别" : "男", "name" : "小刚" }

    删除表db.collectionsNames.drop()

    > show collections
class
student
> db.class.drop()
true
> db.class.drop()
false
> show collections
student
>

    删除数据库db.dropDatabase();

 

 

 

  • MongoDB 索引 

索引是对数据库表中一列或多列的值进行排序的一种结构，可以让我们查询数据库变得更快。数字 1 表示 username 键的索引按升序存储，-1 表示 age 键的索引按照降序方式存储

  1. 创建索引： 
    > db.student.ensureIndex({"name":1})
{
        "createdCollectionAutomatically" : false,
        "numIndexesBefore" : 2,
        "numIndexesAfter" : 2,
        "note" : "all indexes already exist",
        "ok" : 1
}

     

  2. 获取当前集合的索引 
    > db.student.getIndexes()
[
        {
                "v" : 2,
                "key" : {
                        "_id" : 1
                },
                "name" : "_id_",
                "ns" : "school.student"
        },
        {
                "v" : 2,
                "key" : {
                        "name" : 1
                },
                "name" : "name_1",
                "ns" : "school.student"
        },
        {
                "v" : 2,
                "key" : {
                        "age" : 1
                },
                "name" : "age_1",
                "ns" : "school.student"
        }
]

     

  3. 删除索引 
    > db.user.dropIndex({"name":1})
{
        "ok" : 0,
        "errmsg" : "ns not found",
        "code" : 26,
        "codeName" : "NamespaceNotFound"
}

     

  4. 创建唯一索引，如果name添加相同数据的话会添加不上去

    > db.student.ensureIndex({"name":1},{"unique":true})
{
        "ok" : 0,
        "errmsg" : "Index with name: name_1 already exists with different options",
        "code" : 85,
        "codeName" : "IndexOptionsConflict"
}

     

  • 使用nodejs操作数据库

     文档地址参考：http://mongodb.github.io/node-mongodb-native/3.1/quick-start/quick-start/

  1. npm install mangodb --save-dev
  2. nodejs连接数据库 
    const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
const express = require("express");
const app = express()
const url = 'mongodb://localhost:27017'; 

// Database Name
const dbName = 'school';

// Create a new MongoClient
const client = new MongoClient(url, { useNewUrlParser: true });

app.get('/', function(req, res) {
    // Use connect method to connect to the Server
    client.connect(function(err) {

        res.writeHead(200, { "Content-Type": "text/html;charset=UTF8" });
        if (err) {
            res.send("数据库连接失败");
            return;
        }
        assert.equal(null, err);
        res.write("恭喜，数据库已经成功连接 \n");
        console.log("Connected successfully to server");

        const db = client.db(dbName);

    });
})

app.listen(8020)

    控制台输入node app.js,刷新页面http://localhost:8020/出现数据库连接成功就代表连上数据库了

  3. 插入数据 
    const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
const express = require("express");
const app = express()
const url = 'mongodb://localhost:27017';

// Database Name
const dbName = 'school';

// Create a new MongoClient
const client = new MongoClient(url, { useNewUrlParser: true });

app.get('/', function(req, res) {
    // Use connect method to connect to the Server
    client.connect(function(err) {

        res.writeHead(200, { "Content-Type": "text/html;charset=UTF8" });
        if (err) {
            res.send("数据库连接失败");
            return;
        }
        assert.equal(null, err);
        res.write("恭喜，数据库已经成功连接 \n");
        console.log("Connected successfully to server");

        const db = client.db(dbName);



        insertDocuments(db, function() {
            client.close();
        })


    });
})

app.listen(8020)

//插入数据
const insertDocuments = function(db, callback) {
    // Get the documents collection
    const collection = db.collection('student');
    // Insert some documents
    collection.insertMany([
        { name: "静静" }, { name: "忽略了" }, { name: "baby" }
    ], function(err, result) {
        assert.equal(err, null);
        assert.equal(3, result.result.n);
        assert.equal(3, result.ops.length);
        console.log("Inserted 3 documents into the collection");
        callback(result);
    });
}

     

  4. 显示数据 
    const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
const express = require("express");
const app = express()
const url = 'mongodb://localhost:27017';

// Database Name
const dbName = 'school';

// Create a new MongoClient
const client = new MongoClient(url, { useNewUrlParser: true });

app.get('/', function(req, res) {
    // Use connect method to connect to the Server
    client.connect(function(err) {

        res.writeHead(200, { "Content-Type": "text/html;charset=UTF8" });
        if (err) {
            res.send("数据库连接失败");
            return;
        }
        assert.equal(null, err);
        res.write("恭喜，数据库已经成功连接 \n");
        console.log("Connected successfully to server");

        const db = client.db(dbName);

        findDocuments(db, function() {
            client.close();
        })

    });
})

app.listen(8020)

const findDocuments = function(db, callback) {
    // Get the documents collection
    const collection = db.collection('student');
    // Find some documents
    collection.find().toArray(function(err, docs) {
        assert.equal(err, null);
        console.log("Found the following records");
        console.log(docs)
        callback(docs);
    });
}

  5. 改变数据

    const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
const express = require("express");
const app = express()
const url = 'mongodb://localhost:27017';

// Database Name
const dbName = 'school';

// Create a new MongoClient
const client = new MongoClient(url, { useNewUrlParser: true });

app.get('/', function(req, res) {
    // Use connect method to connect to the Server
    client.connect(function(err) {

        res.writeHead(200, { "Content-Type": "text/html;charset=UTF8" });
        if (err) {
            res.send("数据库连接失败");
            return;
        }
        assert.equal(null, err);
        res.write("恭喜，数据库已经成功连接 \n");
        console.log("Connected successfully to server");

        const db = client.db(dbName);

        updateDocument(db, function() {
            client.close();
        })

    });
})

app.listen(8020)

const updateDocument = function(db, callback) {
    // Get the documents collection
    const collection = db.collection('student');
    // Update document where a is 2, set b equal to 1
    collection.updateOne({ a: 2 }, { $set: { b: 1 } }, function(err, result) {
        assert.equal(err, null);
        assert.equal(1, result.result.n);
        console.log("Updated the document with the field a equal to 2");
        callback(result);
    });
}

     

  6. 删除数据

    const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
const express = require("express");
const app = express()
const url = 'mongodb://localhost:27017';

// Database Name
const dbName = 'school';

// Create a new MongoClient
const client = new MongoClient(url, { useNewUrlParser: true });

app.get('/', function(req, res) {
    // Use connect method to connect to the Server
    client.connect(function(err) {

        res.writeHead(200, { "Content-Type": "text/html;charset=UTF8" });
        if (err) {
            res.send("数据库连接失败");
            return;
        }
        assert.equal(null, err);
        res.write("恭喜，数据库已经成功连接 \n");
        console.log("Connected successfully to server");

        const db = client.db(dbName);

        removeDocument(db, function() {
            client.close();
        })

    });
})

app.listen(8020)
const removeDocument = function(db, callback) {
    // Get the documents collection
    const collection = db.collection('student');
    // Delete document where a is 3
    collection.deleteOne({ a: 3 }, function(err, result) {
        assert.equal(err, null);
        assert.equal(1, result.result.n);
        console.log("Removed the document with the field a equal to 3");
        callback(result);
    });
}

     

  7. 添加索引

    const MongoClient = require('mongodb').MongoClient;
const assert = require('assert');
const express = require("express");
const app = express()
const url = 'mongodb://localhost:27017';

// Database Name
const dbName = 'school';

// Create a new MongoClient
const client = new MongoClient(url, { useNewUrlParser: true });

app.get('/', function(req, res) {
    // Use connect method to connect to the Server
    client.connect(function(err) {

        res.writeHead(200, { "Content-Type": "text/html;charset=UTF8" });
        if (err) {
            res.send("数据库连接失败");
            return;
        }
        assert.equal(null, err);
        res.write("恭喜，数据库已经成功连接 \n");
        console.log("Connected successfully to server");

        const db = client.db(dbName);

        indexCollection(db, function() {
            client.close();
        })

    });
})

app.listen(8020)

const indexCollection = function(db, callback) {
    db.collection('student').createIndex({ "a": 1 },
        null,
        function(err, results) {
            console.log(results);
            callback();
        }
    );
};

     

 

 

 

 

 

 

 

 

 

 

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