Mongodb入门5

最近在用MongoDB➕Koa2做个小项目,记录一下：

首先,如何连接线上数据库：

const url = `mongodb://user:pwd@ipaddr:27017/Blog`;
const monk = require('monk');
const db = monk(url);

db.then(() => {
    console.log('MongoDB数据库连接成功!')
})

module.exports = db;

实际操作：

模糊查询

通过$regex来实现

const query = { name: { $regex: new RegExp(name) } };

 

获取查询出来的总数量，分页

        const count = await tagsCol.count(query);
        let list = await tagsCol.find(query, {
            projection: { _id: 0 },
            ...new ctx.MongoQuery.Pagination(page, size),
        });

　MongoQuery.js

var Pagination = require('./Pagination');

function MongoQuery() { }

MongoQuery.Pagination = Pagination;

module.exports = () => async (ctx, next) => {
    ctx.MongoQuery = MongoQuery;
    await next();
}

 

字段筛选

// 0 就是不显示,1就是显示
projection: { _id: 0 },

　　

整体代码如下：

const router = require('koa-router')()
const db = require('../db');
const tagsCol = db.get('tags')
router.prefix('/tags')

/**
 * @ / 查询列表分页
 * @ /insert 新增数据
 * @ /update 修改数据
 * @ /drop 删除数据
 * @ /all 查询所有数据
 */


router.get('/', async (ctx, next) => {
    const { name, page, size } = ctx.query;
    const query = { name: { $regex: new RegExp(name) } };
    try {
        const count = await tagsCol.count(query);
        let list = await tagsCol.find(query, {
            projection: { _id: 0 },
            ...new ctx.MongoQuery.Pagination(page, size),
        });
        ctx.body = new ctx.JsonResponse(200, { list, count })
    } catch (e) {
        ctx.body = new ctx.JsonResponse(500, {})
    }
    db.close();
});

router.get('/insert', async (ctx, next) => {
    ctx.body = '插入成功!';
});



router.post('/update', async (ctx, next) => {
    ctx.body = 'this is a users/bar response'
});


router.get('/drop', async (ctx, next) => {
    const { id } = ctx.query;
    try {
        await tagsCol.remove({ id: Number(id) });
        ctx.body = new ctx.JsonResponse(200)
    } catch (e) {
        ctx.body = new ctx.JsonResponse(500)
    }
    db.close();
});





module.exports = router