uniCloud云函数中通过传统方式操作数据库的-增删改查

来自湖南的阿晨

已于 2023-06-29 20:05:27 修改

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分类专栏： uniapp全栈文章标签：前端

于 2023-03-10 16:52:53 首次发布

本文链接：https://blog.youkuaiyun.com/weixin_52479803/article/details/129439115

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本文详细介绍了如何使用uniCloud的云函数进行数据库的查询、增加、修改和删除操作，包括通过where条件、limit、skip、orderBy和field等方法精细化操作数据，以及批量处理和正则表达式查询。此外，还提到了数据权限系统和JQL语法在数据管理中的应用。

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云函数

可以看做java或者php，作为后端服务

cloudfunctions/myCloud/index.js

exports.main = async (event, context) => {
  const { name, age } = event
    return `我是${name},今年${age}`
};

pages/index/index.vue

//callFunction方法 在前端和云端都可以调用另一个云函数
uniCloud.callFunction({
   name: "myCloud",
   data:{
   name:"小白",
   age:22
 }
}).then(res => {
  console.log(res)
})

浏览器

db.command

查询及更新指令用于在 where 中指定字段需满足的条件，指令可通过 db.command 对象取得

云函数通过传统方式操作数据库

查-cloudfunctions/cloudDome/index.js

const db = uniCloud.database();
exports.main = async (event, context) => {
  // 获取 `users` 集合的引用
  const collection = await db.collection('users').get()

  return collection
};

查-pages/index/index.vue

<template>
  <view class="content" v-for="item in user" :key="item._id">
    {{item.name}} -- {{item.gender}}
  </view>
</template>

<script>
import { reactive, toRefs } from "vue"
  export default {
    setup() {
      const data = reactive({
        user:{}
      })
      uniCloud.callFunction({
        name: "cloudDome",
        data:{}
      }).then(res => {
        data.user = res.result.data
      })
      return {
        ...toRefs(data)
      }
    }
  }
</script>

查-浏览器

doc，指定 id 的记录的引用

const db = uniCloud.database();
exports.main = async (event, context) => {
  const collection = await db.collection('users').doc("640aa8330c801c2ac9373731").get()
  return collection
};

limit

const db = uniCloud.database();
exports.main = async (event, context) => {
  const collection = await db.collection('users').limit(3).get()
  return collection
};

skip，与limit实现翻页效果，skip指跳过的数据

const db = uniCloud.database();
exports.main = async (event, context) => {
  const collection = await db.collection('users').limit(3).skip(3).get()
  return collection
};

orderBy

const db = uniCloud.database();
exports.main = async (event, context) => {
  const collection = await db.collection('users').orderBy("_id","desc").get()
  return collection
};

field，指定返回字段

const db = uniCloud.database();
exports.main = async (event, context) => {
  const collection = await db.collection('users').field({ 'name': true,'_id':false }).get()
  return collection
};

where与查询筛选指令 Query Command

const db = uniCloud.database();
const dbCmd = db.command
exports.main = async (event, context) => {
  const collection = await db.collection('users').where({
  //age:dbCmd.gt(20).and(dbCmd.lt(48)) 
  age:dbCmd.and(dbCmd.gt(8),dbCmd.lt(48))
  //age:dbCmd.or(dbCmd.and(dbCmd.gt(8),dbCmd.lt(48)),dbCmd.eq(50)) 
  }).get()
  return collection
};

正则表达式查询

const db = uniCloud.database();
const dbCmd = db.command
exports.main = async (event, context) => {
  const {  keyWord  } = event
  const collection = await db.collection('users').where({
    name: new RegExp(keyWord,'ig')  //i表示忽略大小写 g表示全局搜索
  }).get()
  return collection
};

增-cloudfunctions/cloudDome/index.js

const db = uniCloud.database();
exports.main = async (event, context) => {
  const obj = {
    "name": "小红",
    "gender": "未知",
    "tel": 1333333333,
    "mail": "564654654@qq.com"
  }
  const collection = await db.collection('users').add(obj)
  return collection
};

增-pages/index/index.vue

uniCloud.callFunction({
        name: "cloudDome",
        data:{}
}).then(res => {
        console.log(res)
})

增-数据库

改-cloudfunctions/cloudDome/index.js

const db = uniCloud.database()
exports.main = async (event, context) => {
  const {  keyWord  } = event
  const collection = await db.collection('users').doc("640aa8330c801c2ac9373731").update({
    name:'张三被改名了',
    age:0
  })
  return {
    message:'修改成功',
    collection
  }
};

改-数据库

批量改-cloudfunctions/cloudDome/index.js

const db = uniCloud.database()
const dbCmd = db.command
exports.main = async (event, context) => {
  const {  keyWord  } = event
  const collection = await db.collection('users').where({
    age:dbCmd.lt(20)
  }).update({
    text:'小于二十岁的小年轻'
  })
  return {
    message:'修改成功',
    collection
  }
};

批量改-数据库

push，向数组尾部追加元素

const db = uniCloud.database()
const dbCmd = db.command
exports.main = async (event, context) => {
  const {  keyWord  } = event
  const collection = await db.collection('users').doc("640aa867f43e603fbeb7771b").update({
    like:dbCmd.push(["烟花"])
  })
  return {
    message:'修改成功',
    collection
  }
};
//中间添加
const collection = await db.collection('users').doc("640aa867f43e603fbeb7771b").update({
    like: dbCmd.push({
      each: ["大","白"],
      position: 1
    })
})

inc，多用户的点赞

  const collection = await db.collection('users').doc("640aa867f43e603fbeb7771b").update({
    love:dbCmd.inc(1)
  })

删-cloudfunctions/cloudDome/index.js

const db = uniCloud.database()
exports.main = async (event, context) => {
  const collection = await db.collection('users').doc("640aae9ff43e603fbeb96150").remove()
  return {
    message: '修改成功',
    collection
  }
};

批量删-cloudfunctions/cloudDome/index.js

const db = uniCloud.database()
const dbCmd = db.command
exports.main = async (event, context) => {
  const collection = await db.collection('users').where({
    name:/小/ig
  }).remove()
  return {
    message: '修改成功',
    collection
  }
};

云对象

展示-cloudfunctions/demoObj/index.obj.js

const db = uniCloud.database()
module.exports = {
  _before: function() { // 通用预处理器 这个不用管，留着就好
  },
  async get(num) {
    return await db.collection("user").limit(num).get()
  },
  add: async () => {
    await db.collection('user').add({
      name:'张麻子',
      content:'我张麻子没有麻子'
    })
  }
}

展示-pages/index/index.vue

  const cloudObj = uniCloud.importObject("demoObj") //导入云对象
    export default {
     setup() {
      cloudObj.get(3).then(res=>{
        console.log(res)
      })
      cloudObj.add().then(res =>{
        console.log(res)
      })
      return {}
    }
}

DB Schema属性节点

foreignKey外键

文章表通过外键的形式绑定user表_id，这样文章就能绑定单个用户，形成关联

//user表
{
    "_id": "606e721280b8450001e773c6",
    "category_id": "606e6feb653b8400017214a3",
    "title": "这里是标题",
    "content": "这里是正文",
    "user_id": "60b9315801033700011ba9ed",
    "publish_date": 1617850851000,
    "publish_ip": "119.131.174.251"
}

//文章表
"properties": {
  "_id": {
    "description": "存储文档 ID（用户 ID），系统自动生成"
  },
  "user_id": {
    "bsonType": "string",
    "description": "文章作者ID， 参考`uni-id-users` 表",
    "foreignKey": "uni-id-users._id",
    "defaultValue": {
      "$env": "uid"
    }
  },
  "title":{},
  "content":{}
}

permission数据权限系统

变量名

说明

auth.uid

用户id

doc	数据库中的目标数据记录，用于匹配记录内容/查询条件

{
  "permission": {
    "read": "doc.status==true", // 任何用户都可以读status字段的值为true的记录，其他记录不可读
    "create": "doc.userid == auth.uid", // 文章中携带的userid 登录 用户id，才能进行发布文章
    "update": false, // 禁止更新数据（admin权限用户不受限）
    "delete": false // 禁止删除数据（admin权限用户不受限）
  }
}

JQL语法

art文章表关联了 user标的_id，并命名为userid

const db = uniCloud.database()

//结尾的方法是getTemp，对usersTemp与artList表过滤 得到临时表
let userTemp = db.collection("usersTemp").field("_id,username,nickname").getTemp();
let artTemp = db.collection("artList").field("userid,title,content,").getTemp();
db.collection(artTemp,userTemp).orderBy("_id desc").get().then(res=>{
  console.log(res)
 })
}