MongoDB Basic Query and monitoring

Basic view:

Show DBS; #查看所有的数据库
Show Collectios; #查看所有的集合
Use DB, switch database, create if not present
Db.dropdatabase (); #删除数据库

Additions and deletions to check:

Db.lhy.insert ({"Name": "Brigitte", "Age": "+", "Sex": "Nan"});
Db.zxy.insert ({"username": "lqx", "Password": "123456"});

Db.zxy.update ({"username": "zxy"},{"username": "Lhy", "Password": "123456"});
Db.zxy.insert ({"Name": "Lhy", "Age": "+", "Sex": "NV"});
Db.zxy.update ({"Age": "},{", "Age": 19});
Db.zxy.update ({"Age": "},{" $set: {' age ': 19}}); #如果要修改指定的key, just use $set.
Db.zxy.remove ({}); #删除整个集合里面的数据
Db.zxy.remove ({"Age": +, "name": "XXX"}); #删除指定的数据
Db.zxy.remove ({"Age": "18"});
Db.zxy.remove ({"Age": "},2"); #删除指定的条数
Db.zxy.find ({"Age": +, "name": "Sex"}); #查询指定的数据
Db.zxy.find (); #查看所有的;
Db.zxy.find ({"Name": "Lqx"}); #查看指定的数据;
Db.zxy.find ({"Name": "Lqx", "Age":); #and
Db.zxy.find (). Pretty (); #格式化数据
Db.zxy.find (). Count (); #查看行数
Db.zxy.find (). Sort ({"Name": -1}) #排序, 1 is ascending,-1 is descending
Db.zxy.find ({$or: [{"Sex": "Nan"},{"name": "Brigitte"}]}). Pretty (); #or操作
Db.zxy.find ({"Age": {$gte:}}). Pretty (); #做笔记操作, greater than or equal to 20
$gte: greater than or equal to
$GT: Greater Than
$lte: Less than or equal to
$LT: Less than

Profile (slow query):
Db.getprofilinglevel () #获取当然profile的级别
Db.setprofilinglevel (1,2000) #记录超过2s
Db.setprofilinglevel (2);
0: Do not open
1: Record slow command, default is greater than 100ms
2: Record all commands
Db.system.profie.find (); #查询慢查询的记录
TS: When the command is executed
OP: Type of operation
Query: Detailed information for this command
ResponseLength: Returns the size of the result set
Ntoreturn: The result set actually returned by this query
Millis: This command executes time-consuming, in milliseconds

Index:
Db.lhy.ensureIndex ({"Name": 1}) #创建一个普通索引
Db.lhy.ensureIndex ({"Name": 1, "Age": 1}); #多列索引
Db.lhy.ensureIndex ({"Name": 1},{"unique": true}); #唯一索引
Db.system.indexes.find (); #查看索引
Db.collections.getIndexes (); #查看当前集合中的索引
Db.lhy.dropIndex ({"Name": 1}); #删除指定索引
Db.user.dropIndexes (); Delete all indexes

Explain (parse):
Db.lhy.find ({"Name": "Zhaoxiaojing"}). Explain (); #解析查询语句
Millis: Time-consuming (ms
Indexbounds: The index used, if this field is not, the index is not used at all

MongoDB Basic Query and monitoring