MONGO practice-operation via JS Shell MONGO

MONGO practice-operation via JS Shell MONGO

Save command:

J={name: "Wangjingjing", age:15}

Db.user.save (j);

Query command:

var cursor = Db.user.find ();

while (Cursor.hasnext ()) Printjson (Cursor.next ());

Printjson (Cursor[4]);

var arr = Cursor.toarray ();

Db.user.find ({name: "wangjingjing"});

Select age from user where name= ' wangjingjing '

Db.user.find ({name: "wangjingjing"},{age:true});

Db.user.findOne ();

Db.user.find (). limit (3);

To modify a command:

Db.user.update ({name: "wangjingjing"},{$set: {name: "Jingjing"}});

Db.user.update ({name: "wangjingjing"},{$inc: {age:10}}); Add 10 to age

Db.user.update ({name: "wangjingjing"},{$push: {habit:["basketball", "Football"]}});

Delete command:

Db.user.remove ({name: "Jingjing"})

Advanced query Commands:

Db.user.find ({x:{$gt: 3}}); X>3

Db.user.find ({x:{$lt: 3}}); X<3

Db.user.find ({x:{$gte: 3}}); X>=3

Db.user.find ({x:{$lte: 3}}); X<=3

Db.user.find ({x:{$lte: 3, $gte: 2}}); 2<=x<=3

var x = {x:[3,4,5]}

Db.user.save (x);

Db.user.find ({x:{$all: [3,4]}}) match

Db.user.find ({x:{$all: [3,4,6]}}) mismatch

Db.user.find ({x:{$in: [3,4,6]}}) match

Db.user.find ({x:{$nin: [3,4,6]}}) match

Db.user.find ({x:{$exsits: true}) matches attributes with X

Db.user.find ({x:{$mod: [6,1]}}) modulo 6 equals 1

Db.user.find ({x:{$ne: 1}}) x!=1

Db.user.find ({$or: [{name: ' Jing '],[age:10]}) or action

Db.user.find ({x:{$size: 3}}) the number of elements in array x is 3

Db.user.find (). Skip (1). Limit (1). Count (True); A second record

Db.user.find (). Sort ({age:1}); ascending

Db.user.find (). Sort ({age:-1}); descending

Export File

mongoexport-d user-c User-o User.bat

Import file

mongoimport-d user-c User User.bat

Backup files

mongodump-d User-o My_user_dump

Recover files

mongorestore-d User My_user_dump\user\

Secure access

Mongod--bind_ip 192.168.1.103--port 28018

MONGO 192.168.1.103:28018

Build an index

Db.user.ensureIndex ({age:1},{background:true}); Ascending

Db.user.getIndexes ();

Interpreting execution

Db.user.find (). Explain ()

Copy set

Replica Set Usage Guide (configured on a single machine)

Brief introduction:

A replica-set is a set of n Mongod services that work together for backup support.

Building a replica-set requires two steps: Start the service on each node, and initialize the set.

In standard mode, 1 set contains 3 nodes. We're going to build one on the same server right now.

Once the Mongod service node is started, we need an instruction to initialize the set. After a few seconds, three nodes will select a

Master node, after which we can write or query data to this set.

Step One:

Allocate the location space for data storage for 3 nodes, respectively

$ mkdir-p/data/r0

$ mkdir-p/DATA/R1

$ mkdir-p/DATA/R2

After that, using the--replset parameter to start the Mongod service, this parameter requires us to specify the name of the Replica-set, here we call this set "foo"

$ mongod--replset foo--port 27017--dbpath/data/r0

$ mongod--replset foo--port 27018--dbpath/data/r1

$ mongod--replset foo--port 27019--dbpath/data/r2

Now 3 nodes are all running up. At this point, each node should have the following warning message:

————————

Mon 2 11:30:19 [startreplsets] replset can ' t get local.

System.replset config from self or any seed (emptyconfig)

————————

Don't be nervous, it's because we haven't initialized this set yet.

Step Two:

We can initialize this set by running the Replsetinitiate command from one of any 3 nodes.

[Email protected] ~$]$ MONGO localhost:27017

MongoDB Shell version:1.6.3

Connecting To:localhost:27017/test

> config = {_id: ' foo ', Members: [

{_id:0, Host: ' localhost:27017 '},

{_id:1, Host: ' localhost:27018 '},

{_id:2, Host: ' localhost:27019 '}]

}

> rs.initiate (config);

{

"Info": "Config now saved locally. Should come online in about a minute. ",

"OK": 1

}

We need to configure the Config object to indicate the name of the set and the members under this set. The config is then passed to Rs.initiate ().

If everything goes well here, we'll have to get a message saying: This set will start in 1 minutes. Within this time period, there is a

The node is selected as the primary node (master node).

If you want to see the current state of this set, use the Rs.status command:

> Rs.status ()

{

"Set": "Foo",

"Date": "Mon-11:39:08 GMT-0400 (EDT)",

"MyState": 1,

"Members": [

{

"Name": "arete.local:27017",

"Self": true,

},

{

"Name": "localhost:27019",

"Health": 1,

"Uptime": 101,

"Lastheartbeat": "Mon-11:39:07 GMT-0400",

},

{

"Name": "localhost:27018",

"Health": 1,

"Uptime": 107,

"Lastheartbeat": "Mon-11:39:07 GMT-0400",

}

],

"OK": 1

}

Here is a value of "mystate", if this value is 1, the description is the Master node (master), or 2, the slave node (slave).

At the same time, each group of Replica sets has only one Primary, which is used to accept write operations. It is then replicated asynchronously to the other member database. Once the primary is dead, it will automatically vote to elect the successor primary, and the original server becomes a regular member after the recovery. Data may be lost if the data has not been copied from the previous primary to the member server.

Primary> Db.test.insert ({"Name": "Foobar", "Age": 25})

Primary> Db.test.find ()

{"_id": ObjectId ("4f4f38fc47db2bfa5ceb2aee"), "name": "Foobar", "Age": 25}

Secondary> Db.test.find ()

Error: {"$err": "Not Master and Slaveok=false", "Code": 13435}

Secondary> Db.test.insert ({"Name": "Foobar", "Age": 25})

Not master

Set Slaveok=ok on the main library (tested to find that you need to set OK from the library)

Primary> Db.getmongo (). Setslaveok ()

secondary> Use test

Switched to DB test

Secondary> Db.test.find ()

{"_id": ObjectId ("4f4f38fc47db2bfa5ceb2aee"), "name": "Foobar", "Age": 25}

Then kill the main library, will be a candidate as the main library, when repaired, it becomes from the library

The ID generated when inserting data is divided into four time stamps, host number, process number, counter

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MONGO practice-operation via JS Shell MONGO