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This article mainly explains the "MongoDB installation and common operation commands", the content of the article is simple and clear, easy to learn and understand, the following please follow the editor's ideas slowly in depth, together to study and learn "MongoDB installation and common operation commands" bar!

Environment: centos7

Ip: 172.16.200.48

.

I. installation and start-up of Mongodb

1. Installation of mongo

Step 1. Download:

# cd / usr/local/src/ # wget https://fastdl.mongodb.org/linux/mongodb-linux-x86_64-rhel70-3.4.3.tgz # tar-zxvf mongodb-linux-x86_64-rhel70-3.4.3.tgz

Step 2. Configure environment variables

# vim / etc/profile

Add the following:

Export MONGODB_HOME=/usr/local/mongodb export PATH=$MONGODB_HOME/bin:$PATH

Step 3. View mongodb version information

# mongod-v

Installation succeeded.

2. The startup of mongo

Step 4. Create a database directory (MongoDB requires a self-built database folder)

# mkdir-p / data/mongodb # mkdir-p / data/mongodb/log # touch / data/logs/mongodb/mongodb.log

Step 5. Add a profile

Create a new mongodb.conf configuration file and start it through this configuration file.

# vim / etc/mongodb.conf

Profile parameter description:

Parameter description of mongodb:


-dbpath database path (data file)


-logpath log file path


-- master designated as the master machine


-- slave specified as slave machine


-- source specifies the IP address of the host machine


-- pologSize specifies that the log file size does not exceed 64m. Because resync is very heavy and time-consuming, * avoid resync by setting a large enough oplogSize (the default oplog size is 5% of the free disk size).


-- added at the end of the logappend log file


-port enable port number


-- fork runs in the background


-- only specifies which database to replicate


-slavedelay refers to the time interval detected from replication


-whether auth needs to verify permission login (username and password)

Configuration file content:

Dbpath=/data/mongodb

Logpath=/data/logs/mongodb/mongodb.log

Logappend=true

Port=27017

Fork=true

# # auth = true # turn it off first, then create the user before starting

Step 6. Start through the configuration file

# mongod-f / etc/mongodb.conf # # launch

The presence of successfully indicates that the startup is successful.

Description

Startup of MongoDB:

It is not recommended to use service mongod start or chkconfig mongod on to start MongoDB, because mongod needs parameters every time it starts, otherwise it will cause errors.

It is recommended to use the mongod command to start. After setting up the configuration file / etc/mongod.conf, use the command to start each time: mongod-f / etc/mongodb.conf

Or set boot restart: echo "mongod-f / etc/mongod.conf" > > / etc/rc.d/rc.local

Shutdown of MongoDB

Forced shutdown of MongoDB: service mongod stop is not recommended

Recommended: close from admin in mongodb

> use admin switched to db admin > db.shutdownServer () server should be down...

Or mongod-- shutdown.

Use shutdownServer to shut down MongoDB, and if there is a MongoDB master-slave server, synchronize the master-slave server before the service is shut down; forced shutdown will not

Step 7. Go to the background of mongodb to manage shell

# cd / usr/local/mongodb/bin #. / mongo

Step 8. Create the database

Creating a database test with use test

Create a database using use DATABASE_NAME. If the database does not exist, create the database, otherwise switch to the specified database.

2. Commands commonly used in Mongo

[root@snails ~] # ps-ef | grep mongod [root@snails ~] # mongo-- host=127.0.0.1-- port=27017 MongoDB shell version: 3.2.7 connecting to: 127.0.0.1:27017/test > show dbs # display database list > show collections # display current database collection (similar to tables in relational database) > show users # display user > use # switch the current database, and create a database if the database does not exist. > db.help () # shows database operation commands, in which there are many commands > db.foo.help () # shows collection operation commands, and there are also many commands. Foo refers to a collection called foo under the current database, not a real command > db.foo.find () # to look up the data of the foo collection in the current database (because there are no conditions) All data will be listed) > db.foo.find ({a: 1}) # look up the foo collection in the current database, provided that there is an attribute called an in the data And the value of an is 1 > db.dropDatabase () # Delete the current database > db.cloneDatabase ("127.0.0.1") # Clone the data from the database on the specified machine to the current database > db.copyDatabase ("mydb", "temp") "127.0.0.1") # copy the local mydb data to the temp database > db.repairDatabase () # repair the current database > db.getName () # View the database currently in use You can also directly use db > db.stats () # to display the current db status > db.version () # current db version > db.getMongo () # to view the linked machine address of the current db > db.serverStatus () # to view the status of the database server

3. Basic operations in Shell: add, delete, modify and check

1. # mongo

Start the mongodb database

2. > db

You can see which database db is currently pointing to.

3. Enter the database > use test

Using use DATABASE_NAME, you can switch the database currently pointed to by the global variable db using the use database name. Note: the use operation can also create a database. If use+ has a database name that does not exist, after use executes, MongoDB will create the corresponding database.

4. Query database > show dbs; (at least one document must be inserted to display the database)

5. Delete database > db.dropDatabase ()

6. Create, delete collections

CreateCollection () method

Db.createCollection (name, options)

In the command, name is the name of the collection to be created. Options is a file that specifies a collection of configurations

Delete collection: drop () method

Db.COLLECTION_NAME.drop () is used to delete a collection from the database

# create collection # enter database mongos > use test; mongos > db.createCollection ("mycollection") {"ok": 1} mongos > show collections; # View collection mycollection # Delete collection # enter database mongos > use testdb; mongos > show collections; mycollection mongos > db.mycollection.drop (); true mongos > show collections

7. Insert document

MongoDB inserts a document into the collection using the insert () or save () method, with the following syntax:

Db.COLLECTION_NAME.insert (document)

Insert document

> use test switched to db test > db.col.insert ({name:'morris',age:22}) WriteResult ({"nInserted": 1})

In the above example, col is the name of the collection, and if the collection is not in the database, MongoDB automatically creates the set and inserts the document.

View inserted documents

> db.col.find () {"_ id": ObjectId ("56e12c22de2a8692a3099065"), "name": "morris", "age": 22}

When we insert a document, if we do not specify _ id,mongodb for the document, an ObjectId will be automatically created for our document that will not be repeated.

Conditional query has been inserted into the document

Db. [collection name] .find (,) # > db.user.find ({name: "user2"}) # # query the record whose name is user2 # > db.user.find ({name: "user2"}, {age:1}); # # query the age field of the record where name is user2

Define variables to insert into the document

> doc= {name:'jack',age:20} {"name", "age": 20} > db.col.insert (doc) WriteResult ({"nInserted": 1}) > db.col.find () {"_ id": ObjectId ("56e12c22de2a8692a3099065"), "name": "morris", "age": 22} {"_ id": ObjectId ("56e12f49de2a8692a3099068"), "name": "jack" "age": 20}

You can also use the db.col.save (document) command to insert a document. If you do not specify the _ id field, the save () method is similar to the insert () method. If you specify the _ id field, the data for that _ id is updated.

Insert multiple documents

If we pass multiple documents into insert, mongodb will insert only * * documents, and only * * documents will be inserted in the following code.

> db.user.find () > db.user.insert ({name: "user1"}, {name: "user2"}) > db.user.find () {"_ id": ObjectId ("519cd757f83727a8baf0a8e2"), "name": "user1"}

If we want to insert more than one document at a time, we can combine the multiple documents into an array so that the insertion can be successful. The example code is as follows:

> db.user.find () > db.user.insert ([{name: "user1"}, {name: "user2"}]) > db.user.find () {"_ id": ObjectId ("519cd842f83727a8baf0a8e3"), "name": "user1"} {"_ id": ObjectId ("519cd842f83727a8baf0a8e4"), "name": "user2"}

We can use javascript to insert data in bulk. Because mongodb shell is simply a javascript shell, javascript code can be run in mongodb shell, so we can use javascript code to insert data in batches. For example, we insert 10 users into the user collection as follows:

> for (iSuppli db.col.find (); {"_ id": ObjectId ("55113e5477eaee1608881c84"), "name": "antian"} # Update document mongos > db.col.update ({"name": "antian"}, {"name": "wuhan"}); # display collection document mongos > db.col.find (); {"_ id": ObjectId ("55113e5477eaee1608881c84"), "name": "wuhan"}

9. Delete document

# Delete document content mongos > db.col.remove ({"name": "antian"}); # Delete collection: db.col.drop ()

10. Restricted record

Mongos > db.col.find ({}, {"sip": 1) .limit (2)

11. Sort documents

Descending order

Mongos > db.col.find ({}, {"age": 1) sort ({"age":-1})

Ascending order

Mongos > db.col.find ({}, {"age": 1) sort ({"age": 1})

twelve。 Create an index

Mongos > db.col.ensureIndex ({"id": 1}) Thank you for reading, these are the contents of "installation of MongoDB and common operation commands". After the study of this article, I believe you have a deeper understanding of the installation of MongoDB and common operation commands, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

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