mongodb (non-relational database: data collection and document storage)
Sequence of operations
1. Open the database server
Mongod --dbpath e:data2(新建的自定义路径)
2, the client opens (not servers, open at the root of the installation mongoose)
3、mongo
4, there are several users view
show dbs
5, using a database (if the user does not create a database)
use + 数据库
6, insert data
db.表名.insert({"":""})
7, view the current collection
show collections
8, view the current contents of the collection
db.当前集合名.find()
9, a plurality of data inserted
for(var i=0;i<10;i++){
db.数据库名.insert({"name":"stu"+i,"age":"10+i"})
}
10, query data
(lt(小于),gt(大于),gte(大于等于),lte(小于等于))
. 11, db collection name .find ({ 'fields': {key: value}})
找到年龄大于15的数据
db.集合名.find({'age':{$gte:15}})
12, remove a piece of data
db.集合名.remove(条件)
13, the query $ or (or table)
db.集合名.find({$or:[{字符:值},{字符:值}]})
14, the query (and represented)
db.集合名.find({"age":{$gt:15,$lt:18}})
15, modify (update)
db.集合名.update({"name":"stu"},{$set:{key:value}})
16, ascending and descending
db.集合名.find().sort({age:-1}) -1表示降序
db.集合名.find().sort({age:1}) 1表示升序
17, delete the current collection
db.集合名.drop()
18, password encryption (one-way encryption and two-way encryption)
1、什么是加密？
crypto 模块提供了加密功能，包括对 OpenSSL 的哈希、HMAC、加密、解密、签名、以及验证功能的一整套封装。
2、如何实现？
const crypto = require('crypto')
const secret = 'abcdefg';
const hash = crypto.createHmac('sha256', secret)
.update('I love cupcakes')
.digest('hex');
console.log(hash);
打印:c0fa1bc00531bd78ef38c628449c5102aeabd49b5dc3a2a516ea6ea959d6658e