mongodb

1. mongodb的基本操作
   
   show dbs; // 查看数据库
   use student; 创建数据库
   //创建表
   db.createCollection("teacher", {
       capped:true,
       size: 10000
   });
   //插入数据
   db.teacher.insertOne({
       "tno": 1,
       "tname": "123",
       "tage":20
   });
   
   db.createCollection("teacher");
   //插入多条数据
   db.teacher.insertMany([
       {
           "tno": 2,
           "tname": "124",
           "tage":21,
           "students":[106,107,108]
       },
       {
           "tno": 3,
           "tname": "125",
           "tage":22,
           "students":[107,108,109]
       }
   ]);
   // 更新数据
   db.teacher.update({
       "tname":"124"
   },{
       $push: {
           "students":125
       }
   })
   db.teacher.find({"tname":"124"});
   //com.mongodb.MongoWriteException: cannot remove from a capped collection: student.teacher
   db.teacher.remove({"tno":123});//
   db.teacher.find({});
   show collections;
   db.teacher.drop();
   db.student.insert({
       "sno":101,
       "sname":"王五",
       "sage":20,
       "ssex":1,
       "hobby": ["吃饭","工作","睡觉"]
   });
   
   db.createCollection("weather", {
       timeseries: {
           timeField:"timestammp",
           metaField:"metadata",
           granularity:"hours"
       }
   });
   db.student.ensureIndex({"sno":1}, {unique:true});
   db.student.insertOne({
       "sno":105,
       "sname":"zhaoliu",
       "sage":24,
       "ssex":1,
       "hobby":["工作","学习"]
   });
   
   --链接查询--
   db.student.aggregate([
       {
           $match:{
               "sno":106
           }
       },
       {
           $lookup:{
               from:"teacher",
               localField:"students",
               foreignField:"sno",
               as:"result"
           }
       }
   ]);
   
   db.student.find({
       "sno":106
   });
   db.student.find({
       "sname":"王五"
   });
   
   db.student.updateMany(
       {
   
           "sname":"zhangsan"
   
       },
       {
   
           $set: {
               "sage":20,
               "ssex":1,
               "hobby":["读书","写字"],
               "ssex":1
           }
       }
   );
   db.student.insertMany([{
       "sno":105,
       "sname":"zhaoliu",
       "sage":24,
       "ssex":1,
       "hobby":["工作","学习"]
   },{
       "sno":106,
       "sname":"zhaoliu",
       "sage":23,
       "ssex":1,
       "hobby":["工作","学习"]
   },{
       "sno":107,
       "sname":"zhaoliu",
       "sage":22,
       "ssex":1,
       "hobby":["工作","学习"]
   }]);
   
   db.student.updateMany({
       "sname":"zhaoliu"
   },{
       $inc:{
           "sage":2
       }
   });
   
   db.student.find({
       "sname":"zhaoliu"
   });
   
   db.student.remove({
       "sname":"zhangsan"
   });
   
   db.student.find({
       "sage": {
           $gt:10,
           $lt:20
       },
       "sname":"zhaoliu",
       "sno": {
           $lte: 103
       }
   });
   
   # -1为降序, 1为升序
   db.student.find({}).sort({"sage":-1}).limit(5).skip(2);
   db.student.remove({});
   db.student.getIndexes();
   db.student.createIndex({
       "sno":1,
       unique:true
   
   });
   db.student.dropIndex("sno_1");

2.mogodb的事务

3.mongodb的数据备份恢复，分片