使用Mongoose对MongoDB进行操作

const mongoose = require('mongoose');
mongoose.connect('mongodb://localhost/test',{
})

Mongoose中的Schema

• 定义Schema categorySchema

const categorySchema = new mongoose.Schema({name:String,description: String,createdAt:{type: Date,default: Date.now}
});

• 通过model方法获得该模型

const Category = mongoose.model('Category', categorySchema);

• 实例化一个新的对象来新增数据

const category = new Category({name: 'test',description: 'test category'
});

• 通过save方法,保持对象到数据库中

category.save(err=>{if(err){console.error(err);return}console.log('saved');
})

• 直接通过模型的Create方法

Category.create({name:'test',description: 'test category'
}, (err, category)=>{if(err){console.error(err);} else {console.log(category)}
});

• 通过find方法,查询name='test’的结果

Category.find({name:'test'
}, (err, res) =>{if(err){console.error(err)} else{console.log(res);}
});

• 删除数据

Category.remove({name:'test'
}).then(()=>{
})

• 更新数据

Category.update({name:'test'
},{name:'test1',description: 'test1'
}).thenm(()=>{})

栗子

• 目录结构如下
  

• 说明:
  course.js:定义了Course表的结构
  coon.js:连接数据库
  db.js:接口的封装
  app.js:负责路由处理和基本的koa相关的配置

• /mongoDB/model/course.js

const mongoose = require('mongoose');
const timeRangeSchema = new mongoose.Schema({hour: {type: Number,max: 24,min: 8},minute: {type: Number,max: 59,min: 0},time: {type: Number,get() {return this.get('hour') * 100 + this.get('minute');}}
});const courseSchema = new mongoose.Schema({name: String,startTime: timeRangeSchema,endTime: timeRangeSchema
})
const Course = mongoose.model('Course', courseSchema);module.exports = Course;

• db.js

const Course = require('./model/course');const getCourseList = async () => {return await Course.find({}).sort({'startTime.time': 1});
}const getCourseById = async (id) => {return await Course.findById(id);
}const getCourseByTime = async (start, end, weekday) => {return await Course.find({weekday: weekday}).where('startTime.time').gte(start.hour * 100 + start.minute).where('endTime.time').lte(end.hour * 100 + end.minute);
}
const addCourse = async (course) => {const { name, weekday, startTime, endTime } = course;const item = await getCourseByTime(startTime, endTime, weekday);if (item) {throw new Error('当前时间段已经安排了课程');}return await Course.create(course);
}const updateCourse = async (id, course) => {return await Course.update({_id: id}, course);
}const removeCourse = async (id) => {return await Course.remove({_id: id});
}module.exports = {getCourseList,getCourseById,addCourse,updateCourse,removeCourse
}

• conn.js

const mongoose = require('mongoose');const connect = async () => {await mongoose.connect('mongodb://localhost/course', {useNewUrlParser: true,useUnifiedTopology: true});
}const close = async () => {await mongoose.connection.close();
}module.exports = { connect, close }

• app.js

const koa = require('koa');
const app = new koa();
const router = new require('koa-router')();
const bodyParser = require('koa-bodyparser');
const {getCourseList,getCourseById,addCourse,updateCourse,removeCourse
} = require('./db');const {connect,close
} = require('./conn');const JSON_MIME = 'application/json';router.get('/course', async ctx => {ctx.type = JSON_MIME;ctx.body = {status: 0,data: await getCourseList()}
});router.get('/course/:id', async ctx => {ctx.type = JSON_MIME;ctx.body = {status: 0,data: await getCourseById(ctx.params.id)}
});router.post('/course', async ctx => {ctx.type = JSON_MIME;await addCourse(ctx.body);ctx.body = {status: 0}
});router.put('/course/:id', async ctx => {await updateCourse(ctx.params.id, ctx.body);ctx.body = {status: 0}
});router.delete('/course/:id', async ctx => {await removeCourse(ctx.params.id);ctx.body = {status: 0}
})app.use(async (ctx, next) => {await connect()await next()await close()
})app.use(bodyParser());
app.use(router.routes());
app.listen(3000, async () => {console.log('Server is running at http://localhost:3000');
})