2023-04-03

使用Node.js開發(fā)App的步驟

創(chuàng)建項(xiàng)目目錄

mkdir myapp
cd myapp
# 合并以上兩步驟
mkdir myapp && cd myapp

初始化

npm init --yes //目的：創(chuàng)建package.json文件，該文件記錄了項(xiàng)目項(xiàng)目信息及項(xiàng)目中所有使用的模塊。

創(chuàng)建項(xiàng)目結(jié)構(gòu)

myapp
- views 
- public
- routes
- package.json
- package-lock.json
- app.js

安裝模塊
```
npm install express
```
引入模塊
```
const express = require('express')
```
寫需求
```
.....
```

網(wǎng)站根目錄

根目錄 VS 用戶根目錄
```
     \           vs        ~
```
查看當(dāng)前位置： pwd
項(xiàng)目根目錄：訪問權(quán)限設(shè)置為公開的磷脯、任何人都可以訪問的声怔。

public目錄

定義

Public 目錄是Node.js中存放網(wǎng)站靜態(tài)文件的目錄。靜態(tài)文件包括：

圖片
css文件
js文件
字體文件

mkdir public && cd public
mkdir css js images

Public : 公共的添瓷、共同的、公開

express框架

框架的核心是構(gòu)造函數(shù)express()
Express()** 構(gòu)造函數(shù)用于創(chuàng)建一個(gè)APP實(shí)例（服務(wù)器類型的app）**
express是基于Node.js平臺(tái)
Node.js平臺(tái)是運(yùn)行js文件的。

Node.js項(xiàng)目目錄
- index.js app.js server.js
- views
  - html視圖模版
    - ejs視圖引擎
- public
  - 引入靜態(tài)資源
普通項(xiàng)目目錄
- index.html
- css
  - style.css
- js
  - Script.js

知識(shí)點(diǎn)1：express.static()

定義

語法

返回值

示例

知識(shí)點(diǎn)2：創(chuàng)建數(shù)據(jù)庫

方案1：創(chuàng)建本地mongodb數(shù)據(jù)庫

啟動(dòng)mongodb數(shù)據(jù)庫

# window系統(tǒng)
服務(wù) => 右鍵 => 啟動(dòng)
# Mac OS
brew services start mongodb/brew/mongodb-community

連接數(shù)據(jù)庫（怎么和數(shù)據(jù)庫通信陷寝？）
1. 可以使用可視化軟件Compass
2. 非可視化軟件：mongosh

mongosh "mongodb://localhost:27017"

創(chuàng)建數(shù)據(jù)庫: zhangsanblog
1. 使用compass手動(dòng)創(chuàng)建
2. 使用mongosh手動(dòng)創(chuàng)建
```
use zhangsanblog
```

創(chuàng)建數(shù)據(jù)庫用戶

語法

Db.createUser({
  user: 'zhangsan',
  pwd: '123456',
  roles: [{ role:"readWrite",db:"config"},"clusterAdmin"],
  roles: ["readWrite"]
})

方案2：創(chuàng)建云數(shù)據(jù)庫

登錄Atlas賬戶
創(chuàng)建數(shù)據(jù)庫： zhangsanblog
創(chuàng)建用戶: zhangsan Zxcvbn123456

知識(shí)點(diǎn)3：連接字符串

定義

連接字符串特指在App開發(fā)過程中連接數(shù)據(jù)庫的地址。

語法

"協(xié)議://用戶名:密碼@數(shù)據(jù)庫地址/數(shù)據(jù)庫名"

云數(shù)據(jù)庫的連接字符串

從云數(shù)據(jù)庫復(fù)制的連接字符串：
'mongodb+srv://<username>:<password>@zhangsanblog.4t6hj0s.mongodb.net/?retryWrites=true&w=majority'
用你的用戶名和密碼替換<username>和<password>
'mongodb+srv://zhaolusiblong:202303013@zhaolusiblong.towdlc9.mongodb.net/?retryWrites=true&w=majority'

本地?cái)?shù)據(jù)庫的連接字符串

"mongodb://zhangsan:123456@127.0.0.1:27107/zhangsanblog"
"mongodb://zhangsan:123456@localhost:27107/zhangsanblog"

知識(shí)點(diǎn)4：Node和MongoDB的通信

通信方式有兩種：

Mongodb模塊:
- mongodb模塊是Node.js原生提供的與mongoDB數(shù)據(jù)庫通信的API其馏。
Mongoose模塊:
- 是第三方提供的在Node平臺(tái)與MongoDB數(shù)據(jù)庫通信的方式凤跑。
- Mongoose是一個(gè)庫。
- 庫：就是函數(shù)的集合尝偎。
- Mongoose庫包裹Node API饶火。

知識(shí)點(diǎn)5：使用Mongoose模塊連接數(shù)據(jù)庫

const mongoose = require('mongoose')

mongoose.connect(uri)
    .then((result) => {
        console.log('數(shù)據(jù)庫已經(jīng)連接')
    })
    .catch( err => console.log(err))

mongoose是什么？

核心：mongoose()構(gòu)造函數(shù)
mongoose是一個(gè)ODM（對(duì)象數(shù)據(jù)模型）致扯。（object Data Model）
使用js對(duì)象的語法來映射mongoose數(shù)據(jù)庫種的表和document
collection：數(shù)據(jù)庫中的表肤寝；
document：數(shù)據(jù)中的文檔；

打印mongoose

const mongoose = require('mongoose') 引入mongoose模塊會(huì)自動(dòng)創(chuàng)建mongoose實(shí)例對(duì)象抖僵。

mongoose是一個(gè)對(duì)象
Mongoose.connections 屬性
mongoose.Schema :構(gòu)造函數(shù)
Mongoose.model：函數(shù)

Mongoose {
  connections: [
    NativeConnection {
      base: [Circular *1],
      collections: {},
      models: {},
      config: {},
      replica: false,
      options: null,
      otherDbs: [],
      relatedDbs: {},
      states: [Object: null prototype],
      _readyState: 0,
      _closeCalled: false,
      _hasOpened: false,
      plugins: [],
      id: 0,
      _queue: [],
      _listening: false
    }
  ],
  nextConnectionId: 1,
  models: {},
  events: EventEmitter {
    _events: [Object: null prototype] {},
    _eventsCount: 0,
    _maxListeners: undefined,
    [Symbol(kCapture)]: false
  },
  __driver: {
    Collection: [Function: NativeCollection],
    Connection: [Function: NativeConnection] { STATES: [Object: null prototype] }
  },
  options: {
    pluralization: true,
    autoIndex: true,
    autoCreate: true,
    [Symbol(mongoose:default)]: true
  },
  _pluralize: [Function: pluralize],
  Schema: [Function: Schema] {
    reserved: [Object: null prototype] {
      validate: 1,
      toObject: 1,
      save: 1,
      remove: 1,
      populated: 1,
      isNew: 1,
      isModified: 1,
      init: 1,
      get: 1,
      errors: 1,
      collection: 1,
      removeListener: 1,
      listeners: 1,
      emit: 1,
      prototype: 1
    },
    Types: {
      String: [Function],
      Number: [Function],
      Boolean: [Function],
      DocumentArray: [Function],
      Subdocument: [Function],
      Array: [Function],
      Buffer: [Function],
      Date: [Function],
      ObjectId: [Function],
      Mixed: [Function],
      Decimal: [Function],
      Decimal128: [Function],
      Map: [Function],
      UUID: [Function],
      Oid: [Function],
      Object: [Function],
      Bool: [Function],
      ObjectID: [Function]
    },
    ObjectId: [Function: ObjectId] {
      schemaName: 'ObjectId',
      defaultOptions: {},
      get: [Function (anonymous)],
      set: [Function: set],
      _checkRequired: [Function (anonymous)],
      _cast: [Function: castObjectId],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    }
  },
  model: [Function (anonymous)],
  plugins: [
    [ [Function: removeSubdocs], [Object] ],
    [ [Function: saveSubdocs], [Object] ],
    [ [Function], [Object] ],
    [ [Function: trackTransaction], [Object] ],
    [ [Function: validateBeforeSave], [Object] ]
  ],
  default: [Circular *1],
  mongoose: [Circular *1],
  cast: [Function: cast],
  STATES: [Object: null prototype] {
    '0': 'disconnected',
    '1': 'connected',
    '2': 'connecting',
    '3': 'disconnecting',
    '99': 'uninitialized',
    disconnected: 0,
    connected: 1,
    connecting: 2,
    disconnecting: 3,
    uninitialized: 99
  },
  setDriver: [Function: setDriver],
  set: [Function (anonymous)],
  get: [Function (anonymous)],
  createConnection: [Function (anonymous)],
  connect: [AsyncFunction: connect],
  disconnect: [AsyncFunction: disconnect],
  startSession: [Function (anonymous)],
  pluralize: [Function (anonymous)],
  deleteModel: [Function (anonymous)],
  modelNames: [Function (anonymous)],
  plugin: [Function (anonymous)],
  version: '7.0.3',
  Mongoose: [Function: Mongoose],
  SchemaType: [Function: SchemaType] {
    cast: [Function: cast],
    set: [Function: set],
    get: [Function (anonymous)],
    _isRef: [Function (anonymous)],
    checkRequired: [Function (anonymous)],
    CastError: [class CastError extends MongooseError],
    ValidatorError: [class ValidatorError extends MongooseError]
  },
  SchemaTypes: {
    String: [Function: SchemaString] {
      schemaName: 'String',
      defaultOptions: {},
      _cast: [Function: castString],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      get: [Function (anonymous)],
      set: [Function: set],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    Number: [Function: SchemaNumber] {
      get: [Function (anonymous)],
      set: [Function: set],
      _cast: [Function: castNumber],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      schemaName: 'Number',
      defaultOptions: {},
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    Boolean: [Function: SchemaBoolean] {
      schemaName: 'Boolean',
      defaultOptions: {},
      _cast: [Function],
      set: [Function: set],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)],
      '$conditionalHandlers': [Object]
    },
    DocumentArray: [Function: DocumentArrayPath] {
      schemaName: 'DocumentArray',
      options: [Object],
      defaultOptions: {},
      set: [Function: set]
    },
    Subdocument: [Function: SubdocumentPath] {
      defaultOptions: {},
      set: [Function: set]
    },
    Array: [Function: SchemaArray] {
      schemaName: 'Array',
      options: [Object],
      defaultOptions: {},
      set: [Function: set],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    Buffer: [Function: SchemaBuffer] {
      schemaName: 'Buffer',
      defaultOptions: {},
      _checkRequired: [Function (anonymous)],
      set: [Function: set],
      checkRequired: [Function (anonymous)]
    },
    Date: [Function: SchemaDate] {
      schemaName: 'Date',
      defaultOptions: {},
      _cast: [Function: castDate],
      set: [Function: set],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    ObjectId: [Function: ObjectId] {
      schemaName: 'ObjectId',
      defaultOptions: {},
      get: [Function (anonymous)],
      set: [Function: set],
      _checkRequired: [Function (anonymous)],
      _cast: [Function: castObjectId],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    Mixed: [Function: Mixed] {
      schemaName: 'Mixed',
      defaultOptions: {},
      get: [Function (anonymous)],
      set: [Function: set]
    },
    Decimal: [Function: Decimal128] {
      schemaName: 'Decimal128',
      defaultOptions: {},
      _cast: [Function: castDecimal128],
      set: [Function: set],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    Decimal128: [Function: Decimal128] {
      schemaName: 'Decimal128',
      defaultOptions: {},
      _cast: [Function: castDecimal128],
      set: [Function: set],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    Map: [class Map extends SchemaType] {
      schemaName: 'Map',
      defaultOptions: {}
    },
    UUID: [Function: SchemaUUID] {
      schemaName: 'UUID',
      defaultOptions: {},
      _cast: [Function (anonymous)],
      set: [Function: set],
      cast: [Function: cast],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    Oid: [Function: ObjectId] {
      schemaName: 'ObjectId',
      defaultOptions: {},
      get: [Function (anonymous)],
      set: [Function: set],
      _checkRequired: [Function (anonymous)],
      _cast: [Function: castObjectId],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    },
    Object: [Function: Mixed] {
      schemaName: 'Mixed',
      defaultOptions: {},
      get: [Function (anonymous)],
      set: [Function: set]
    },
    Bool: [Function: SchemaBoolean] {
      schemaName: 'Boolean',
      defaultOptions: {},
      _cast: [Function],
      set: [Function: set],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      _checkRequired: [Function (anonymous)],
      checkRequired: [Function (anonymous)],
      '$conditionalHandlers': [Object]
    },
    ObjectID: [Function: ObjectId] {
      schemaName: 'ObjectId',
      defaultOptions: {},
      get: [Function (anonymous)],
      set: [Function: set],
      _checkRequired: [Function (anonymous)],
      _cast: [Function: castObjectId],
      cast: [Function: cast],
      _defaultCaster: [Function (anonymous)],
      checkRequired: [Function (anonymous)]
    }
  },
  VirtualType: [Function: VirtualType],
  Types: {
    Array: [Function: MongooseArray],
    Buffer: [Function: MongooseBuffer] {
      pathSymbol: Symbol(mongoose#Buffer#_path),
      mixin: [Object],
      Binary: [Function]
    },
    Embedded: [Function: ArraySubdocument] {
      _events: undefined,
      _eventsCount: 0,
      _maxListeners: undefined,
      setMaxListeners: [Function: setMaxListeners],
      getMaxListeners: [Function: getMaxListeners],
      emit: [Function: emit],
      addListener: [Function: addListener],
      on: [Function: addListener],
      prependListener: [Function: prependListener],
      once: [Function: once],
      prependOnceListener: [Function: prependOnceListener],
      removeListener: [Function: removeListener],
      off: [Function: removeListener],
      removeAllListeners: [Function: removeAllListeners],
      listeners: [Function: listeners],
      rawListeners: [Function: rawListeners],
      listenerCount: [Function: listenerCount],
      eventNames: [Function: eventNames]
    },
    Document: [Function: ArraySubdocument] {
      _events: undefined,
      _eventsCount: 0,
      _maxListeners: undefined,
      setMaxListeners: [Function: setMaxListeners],
      getMaxListeners: [Function: getMaxListeners],
      emit: [Function: emit],
      addListener: [Function: addListener],
      on: [Function: addListener],
      prependListener: [Function: prependListener],
      once: [Function: once],
      prependOnceListener: [Function: prependOnceListener],
      removeListener: [Function: removeListener],
      off: [Function: removeListener],
      removeAllListeners: [Function: removeAllListeners],
      listeners: [Function: listeners],
      rawListeners: [Function: rawListeners],
      listenerCount: [Function: listenerCount],
      eventNames: [Function: eventNames]
    },
    DocumentArray: [Function: MongooseDocumentArray],
    Decimal128: [class Decimal128 extends BSONValue],
    ObjectId: [class ObjectId extends BSONValue] { index: 7107676 },
    Map: [class MongooseMap extends Map],
    Subdocument: [Function: Subdocument]
  },
  Query: [Function: Query] {
    base: {
      toConstructor: [Function: toConstructor],
      setOptions: [Function (anonymous)],
      collection: [Function: collection],
      collation: [Function (anonymous)],
      '$where': [Function (anonymous)],
      where: [Function (anonymous)],
      equals: [Function: equals],
      eq: [Function: eq],
      or: [Function: or],
      nor: [Function: nor],
      and: [Function: and],
      gt: [Function (anonymous)],
      gte: [Function (anonymous)],
      lt: [Function (anonymous)],
      lte: [Function (anonymous)],
      ne: [Function (anonymous)],
      in: [Function (anonymous)],
      nin: [Function (anonymous)],
      all: [Function (anonymous)],
      regex: [Function (anonymous)],
      size: [Function (anonymous)],
      maxDistance: [Function (anonymous)],
      minDistance: [Function (anonymous)],
      mod: [Function (anonymous)],
      exists: [Function (anonymous)],
      elemMatch: [Function (anonymous)],
      within: [Function: within],
      box: [Function (anonymous)],
      polygon: [Function (anonymous)],
      circle: [Function (anonymous)],
      near: [Function: near],
      intersects: [Function: intersects],
      geometry: [Function: geometry],
      select: [Function: select],
      slice: [Function (anonymous)],
      sort: [Function (anonymous)],
      limit: [Function (anonymous)],
      skip: [Function (anonymous)],
      batchSize: [Function (anonymous)],
      comment: [Function (anonymous)],
      maxTimeMS: [Function (anonymous)],
      maxTime: [Function (anonymous)],
      hint: [Function (anonymous)],
      j: [Function: j],
      slaveOk: [Function (anonymous)],
      setReadPreference: [Function (anonymous)],
      read: [Function (anonymous)],
      r: [Function (anonymous)],
      readConcern: [Function (anonymous)],
      tailable: [Function (anonymous)],
      w: [Function: writeConcern],
      writeConcern: [Function: writeConcern],
      wTimeout: [Function: wtimeout],
      wtimeout: [Function: wtimeout],
      merge: [Function (anonymous)],
      find: [Function (anonymous)],
      _find: [AsyncFunction: _find],
      cursor: [Function (anonymous)],
      findOne: [Function (anonymous)],
      _findOne: [AsyncFunction: _findOne],
      count: [Function (anonymous)],
      _count: [AsyncFunction: _count],
      distinct: [Function (anonymous)],
      _distinct: [AsyncFunction: _distinct],
      updateMany: [Function: updateMany],
      _updateMany: [AsyncFunction (anonymous)],
      updateOne: [Function: updateOne],
      _updateOne: [AsyncFunction (anonymous)],
      replaceOne: [Function: replaceOne],
      _replaceOne: [AsyncFunction (anonymous)],
      deleteOne: [Function (anonymous)],
      _deleteOne: [AsyncFunction (anonymous)],
      deleteMany: [Function (anonymous)],
      _deleteMany: [AsyncFunction (anonymous)],
      findOneAndUpdate: [Function (anonymous)],
      _findOneAndUpdate: [AsyncFunction (anonymous)],
      findOneAndDelete: [Function (anonymous)],
      findOneAndRemove: [Function (anonymous)],
      _findOneAndRemove: [AsyncFunction (anonymous)],
      setTraceFunction: [Function (anonymous)],
      exec: [AsyncFunction: exec],
      then: [AsyncFunction (anonymous)],
      selected: [Function: selected],
      selectedInclusively: [Function: selectedInclusively],
      selectedExclusively: [Function: selectedExclusively],
      _mergeUpdate: [Function (anonymous)],
      _optionsForExec: [Function (anonymous)],
      _fieldsForExec: [Function (anonymous)],
      _updateForExec: [Function (anonymous)],
      _ensurePath: [Function (anonymous)],
      _validate: [Function (anonymous)]
    },
    'use$geoWithin': true
  },
  Model: Model { undefined },
  Document: [Function: Document] {
    _events: undefined,
    _eventsCount: 0,
    _maxListeners: undefined,
    setMaxListeners: [Function: setMaxListeners],
    getMaxListeners: [Function: getMaxListeners],
    emit: [Function: emit],
    addListener: [Function: addListener],
    on: [Function: addListener],
    prependListener: [Function: prependListener],
    once: [Function: once],
    prependOnceListener: [Function: prependOnceListener],
    removeListener: [Function: removeListener],
    off: [Function: removeListener],
    removeAllListeners: [Function: removeAllListeners],
    listeners: [Function: listeners],
    rawListeners: [Function: rawListeners],
    listenerCount: [Function: listenerCount],
    eventNames: [Function: eventNames],
    ValidationError: [class ValidationError extends MongooseError]
  },
  ObjectId: [Function: ObjectId] {
    schemaName: 'ObjectId',
    defaultOptions: {},
    get: [Function (anonymous)],
    set: [Function: set],
    _checkRequired: [Function (anonymous)],
    _cast: [Function: castObjectId],
    cast: [Function: cast],
    _defaultCaster: [Function (anonymous)],
    checkRequired: [Function (anonymous)]
  },
  isValidObjectId: [Function (anonymous)],
  isObjectIdOrHexString: [Function (anonymous)],
  syncIndexes: [Function (anonymous)],
  Decimal128: [Function: Decimal128] {
    schemaName: 'Decimal128',
    defaultOptions: {},
    _cast: [Function: castDecimal128],
    set: [Function: set],
    cast: [Function: cast],
    _defaultCaster: [Function (anonymous)],
    _checkRequired: [Function (anonymous)],
    checkRequired: [Function (anonymous)]
  },
  Mixed: [Function: Mixed] {
    schemaName: 'Mixed',
    defaultOptions: {},
    get: [Function (anonymous)],
    set: [Function: set]
  },
  Date: [Function: SchemaDate] {
    schemaName: 'Date',
    defaultOptions: {},
    _cast: [Function: castDate],
    set: [Function: set],
    cast: [Function: cast],
    _defaultCaster: [Function (anonymous)],
    _checkRequired: [Function (anonymous)],
    checkRequired: [Function (anonymous)]
  },
  Number: [Function: SchemaNumber] {
    get: [Function (anonymous)],
    set: [Function: set],
    _cast: [Function: castNumber],
    cast: [Function: cast],
    _defaultCaster: [Function (anonymous)],
    schemaName: 'Number',
    defaultOptions: {},
    _checkRequired: [Function (anonymous)],
    checkRequired: [Function (anonymous)]
  },
  Error: [class MongooseError extends Error] {
    messages: {
      DocumentNotFoundError: null,
      general: [Object],
      Number: [Object],
      Date: [Object],
      String: [Object]
    },
    Messages: {
      DocumentNotFoundError: null,
      general: [Object],
      Number: [Object],
      Date: [Object],
      String: [Object]
    },
    DocumentNotFoundError: [class DocumentNotFoundError extends MongooseError],
    CastError: [class CastError extends MongooseError],
    ValidationError: [class ValidationError extends MongooseError],
    ValidatorError: [class ValidatorError extends MongooseError],
    VersionError: [class VersionError extends MongooseError],
    ParallelSaveError: [class ParallelSaveError extends MongooseError],
    OverwriteModelError: [class OverwriteModelError extends MongooseError],
    MissingSchemaError: [class MissingSchemaError extends MongooseError],
    MongooseServerSelectionError: [class MongooseServerSelectionError extends MongooseError],
    DivergentArrayError: [class DivergentArrayError extends MongooseError],
    StrictModeError: [class StrictModeError extends MongooseError],
    StrictPopulateError: [class StrictPopulateError extends MongooseError]
  },
  now: [Function: now],
  CastError: [class CastError extends MongooseError],
  SchemaTypeOptions: [class SchemaTypeOptions],
  mongo: {
    BSON: [Getter],
    Binary: [Getter],
    BSONRegExp: [Getter],
    BSONSymbol: [Getter],
    BSONType: [Getter],
    Code: [Getter],
    DBRef: [Getter],
    Decimal128: [Getter],
    Double: [Getter],
    Int32: [Getter],
    Long: [Getter],
    MaxKey: [Getter],
    MinKey: [Getter],
    ObjectId: [Getter],
    Timestamp: [Getter],
    MongoBulkWriteError: [Getter],
    ChangeStreamCursor: [Getter],
    MongoAPIError: [Getter],
    MongoAWSError: [Getter],
    MongoBatchReExecutionError: [Getter],
    MongoChangeStreamError: [Getter],
    MongoCompatibilityError: [Getter],
    MongoCursorExhaustedError: [Getter],
    MongoCursorInUseError: [Getter],
    MongoDecompressionError: [Getter],
    MongoDriverError: [Getter],
    MongoError: [Getter],
    MongoExpiredSessionError: [Getter],
    MongoGridFSChunkError: [Getter],
    MongoGridFSStreamError: [Getter],
    MongoInvalidArgumentError: [Getter],
    MongoKerberosError: [Getter],
    MongoMissingCredentialsError: [Getter],
    MongoMissingDependencyError: [Getter],
    MongoNetworkError: [Getter],
    MongoNetworkTimeoutError: [Getter],
    MongoNotConnectedError: [Getter],
    MongoParseError: [Getter],
    MongoRuntimeError: [Getter],
    MongoServerClosedError: [Getter],
    MongoServerError: [Getter],
    MongoServerSelectionError: [Getter],
    MongoSystemError: [Getter],
    MongoTailableCursorError: [Getter],
    MongoTopologyClosedError: [Getter],
    MongoTransactionError: [Getter],
    MongoUnexpectedServerResponseError: [Getter],
    MongoWriteConcernError: [Getter],
    AbstractCursor: [Getter],
    Admin: [Getter],
    AggregationCursor: [Getter],
    CancellationToken: [Getter],
    ChangeStream: [Getter],
    ClientSession: [Getter],
    Collection: [Getter],
    Db: [Getter],
    FindCursor: [Getter],
    GridFSBucket: [Getter],
    GridFSBucketReadStream: [Getter],
    GridFSBucketWriteStream: [Getter],
    ListCollectionsCursor: [Getter],
    ListIndexesCursor: [Getter],
    MongoClient: [Getter],
    OrderedBulkOperation: [Getter],
    UnorderedBulkOperation: [Getter],
    BatchType: [Getter],
    GSSAPICanonicalizationValue: [Getter],
    AuthMechanism: [Getter],
    Compressor: [Getter],
    CURSOR_FLAGS: [Getter],
    AutoEncryptionLoggerLevel: [Getter],
    MongoErrorLabel: [Getter],
    ExplainVerbosity: [Getter],
    ServerApiVersion: [Getter],
    ReturnDocument: [Getter],
    ProfilingLevel: [Getter],
    ReadConcernLevel: [Getter],
    ReadPreferenceMode: [Getter],
    ServerType: [Getter],
    TopologyType: [Getter],
    ReadConcern: [Getter],
    ReadPreference: [Getter],
    WriteConcern: [Getter],
    CommandFailedEvent: [Getter],
    CommandStartedEvent: [Getter],
    CommandSucceededEvent: [Getter],
    ConnectionCheckedInEvent: [Getter],
    ConnectionCheckedOutEvent: [Getter],
    ConnectionCheckOutFailedEvent: [Getter],
    ConnectionCheckOutStartedEvent: [Getter],
    ConnectionClosedEvent: [Getter],
    ConnectionCreatedEvent: [Getter],
    ConnectionPoolClearedEvent: [Getter],
    ConnectionPoolClosedEvent: [Getter],
    ConnectionPoolCreatedEvent: [Getter],
    ConnectionPoolMonitoringEvent: [Getter],
    ConnectionPoolReadyEvent: [Getter],
    ConnectionReadyEvent: [Getter],
    ServerClosedEvent: [Getter],
    ServerDescriptionChangedEvent: [Getter],
    ServerHeartbeatFailedEvent: [Getter],
    ServerHeartbeatStartedEvent: [Getter],
    ServerHeartbeatSucceededEvent: [Getter],
    ServerOpeningEvent: [Getter],
    TopologyClosedEvent: [Getter],
    TopologyDescriptionChangedEvent: [Getter],
    TopologyOpeningEvent: [Getter],
    SrvPollingEvent: [Getter]
  },
  mquery: [Function: Query] {
    permissions: {
      distinct: [Function],
      findOneAndRemove: [Function],
      findOneAndUpdate: [Function],
      count: [Function]
    },
    _isPermitted: [Function (anonymous)],
    canMerge: [Function (anonymous)],
    setGlobalTraceFunction: [Function (anonymous)],
    utils: {
      clone: [Function: clone],
      cloneObject: [Function: cloneObject],
      cloneArray: [Function: cloneArray],
      merge: [Function: merge],
      mergeClone: [Function: mergeClone],
      readPref: [Function: readPref],
      readConcern: [Function: readConcern],
      toString: [Function (anonymous)],
      isObject: [Function (anonymous)],
      keys: [Function: keys],
      create: [Function: create],
      inherits: [Function (anonymous)],
      isArgumentsObject: [Function (anonymous)]
    },
    env: { isNode: [Array], isMongo: false, isBrowser: false, type: 'node' },
    Collection: [class NodeCollection extends Collection],
    BaseCollection: [Function: Collection] { methods: [Array] }
  },
  sanitizeFilter: [Function: sanitizeFilter],
  trusted: [Function: trusted],
  skipMiddlewareFunction: [Function: skipWrappedFunction],
  overwriteMiddlewareResult: [Function: overwriteResult]
}

mongoose是什么鲤看？

Mongoose 是 MongoDB 的對(duì)象建模工具。

Mongoose 用于和MongoDB 通信(增刪改查)耍群。

Mongoose運(yùn)行在Node.js 平臺(tái)义桂。

Mongoose()是一個(gè)構(gòu)造函數(shù)
引入mongoose模塊會(huì)自動(dòng)創(chuàng)建一個(gè)mongoose實(shí)例對(duì)象。

mongoose.connect()

定義：

mongoose.connect()用于連接MongoDB數(shù)據(jù)庫蹈垢。

它是一個(gè)異步函數(shù)慷吊。

語法

mongoose.connect(uri)
mongoose.connect(數(shù)據(jù)庫連接字符串)

返回值

返回一個(gè)Promise對(duì)象

示例

promise.then()

定義

then()方法為promise綁定回調(diào)函數(shù)。

語法

promise.then(resolved,rejected)
promise.then((data) => {
  //在異步操作成功時(shí)曹抬，處理異步操作的結(jié)果
},(error) => {
  //在異步操作失敗時(shí)溉瓶，輸出錯(cuò)誤的原因
})

//一個(gè)參數(shù)：大多時(shí)候我們更加關(guān)注異步操作成功
promise.then((resolved) => {
  //在異步操作成功時(shí)，處理異步操作的結(jié)果
})

//then()方法可以鏈?zhǔn)秸{(diào)用
promise.then((resolved) => {
  //在異步操作成功時(shí)，處理異步操作的結(jié)果
})
  .then((resolved) => {})
    .then((resolved) => {})
    .catch(error => {//捕獲錯(cuò)誤信息})

then() 方法最多接受兩個(gè)參數(shù)：

resolved :Promise 已完成的回調(diào)函數(shù)堰酿。
rejected: Promise已拒絕的回調(diào)函數(shù)疾宏。

返回值

返回一個(gè)等效的prmose對(duì)象。

示例

promise.catch()

定義：

catch()方法用于為promise對(duì)象綁定請(qǐng)求失敗時(shí)的回調(diào)函數(shù)触创。

catch()方法用于捕獲錯(cuò)誤信息坎藐。

語法

promise.catch((err) => {})

返回值

返回一個(gè)promise對(duì)象。

示例

mongoose.model()

定義：

用于創(chuàng)建與MongoDB數(shù)據(jù)庫通信的工具哼绑。

該工具在這里意思就是：指一個(gè)構(gòu)造函數(shù)岩馍。

構(gòu)造函數(shù)可以實(shí)例化一個(gè)對(duì)象。

通過實(shí)例對(duì)象的方法與數(shù)據(jù)庫進(jìn)行通信凌那。

語法

const Blog = mongoose.model('模型名稱',模型原型)
const Blog = mongoose.model('模型名稱',blogSchema)

返回值

返回大寫的構(gòu)造函數(shù)（Model()）

示例

Schema()

定義：

Schema()是一個(gè)構(gòu)造函數(shù)/類兼雄。

Schema()用于描述數(shù)據(jù)表的結(jié)構(gòu)。

數(shù)據(jù)庫：由多個(gè)數(shù)據(jù)庫表構(gòu)成
數(shù)據(jù)庫表：由多個(gè)document(記錄)構(gòu)成帽蝶。
Document: 由字段和值構(gòu)成赦肋。

語法

 new Schema({定義表結(jié)構(gòu)},{選項(xiàng)對(duì)象})

const blogSchema = new Schema({
  //定義title字段
  title: {
    //字段類型：字符串
    type: String,
    //字段是否必寫: true
    required: true
  },
  body: {
    type: String,
    required: true
  }
}, {})

定義表結(jié)構(gòu)：定義有哪些字段、每個(gè)字段的數(shù)據(jù)類型励稳、是否必填等
選項(xiàng)對(duì)象：提供了一些參數(shù)佃乘，用來配置第一個(gè)參數(shù)

返回值

返回schema實(shí)例對(duì)象,表示數(shù)據(jù)結(jié)構(gòu)。

示例：

Bootstrap:.Containers

<div class='Containers'></div>
-定義：
- 表示一個(gè)容器驹尼。
- Containers類是Bootstrap是一個(gè)構(gòu)建基本結(jié)構(gòu)的類趣避；
- 用法1：寬度固定

- 用法2：寬度不固定100%；流式布局

------
Background：背景色+文字顏色

bg-body-tertiary


-------
#.link：設(shè)置鏈接顏色
- 定義：link-primary

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