MongoDB

Installation

Ubuntu 14.04, 15.10

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv EA312927
echo "deb http://repo.mongodb.org/apt/ubuntu trusty/mongodb-org/3.2 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-3.2.list
sudo apt-get update
sudo apt-get install -y mongodb-org

Check if service is active

sudo systemctl status mongd

If it's not working

sudo reboot

If it still not working, create and run the script enable_mongo.sh with:

echo '[Unit]
Description=High-performance, schema-free document-oriented database
After=syslog.target network.target
 
[Service]
User=mongodb
Group=mongodb
ExecStart=/usr/bin/mongod -f /etc/mongod.conf
 
[Install]
WantedBy=multi-user.target' > /lib/systemd/system/mongod.service

# Setup the required directories
mkdir -p /var/run/mongodb/
mkdir -p /var/log/mongodb/
mkdir -p /var/lib/mongodb/
mkdir -p /data/db/

chown mongodb:mongodb /var/run/mongodb/
chown mongodb:mongodb /var/log/mongodb/
chown mongodb:mongodb /var/lib/mongodb/
chown mongodb:mongodb /data/db

chmod 0755 /var/log/mongodb/
chmod 0755 /var/run/mongodb/
chmod 0755 /var/lib/mongodb/
chmod 0755 /data/db/

# Start the new service and enable it on boot
systemctl --system daemon-reload
systemctl enable mongod.service

echo "Starting"
systemctl start mongod.service

# Specific version install: sudo apt-get install -y mongodb-org=3.2.1 mongodb-org-server=3.2.1 mongodb-org-shell=3.2.1 mongodb-org-mongos=3.2.1 mongodb-org-tools=3.2.1

Enable authentication

• Connect to mongo instance:

mongo

• Add an admin user:

use admin
db.createUser(
  {
    user: "myUserAdmin",
    pwd: "abc123",
    roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
  }
)

• Edit configuration file

sudo nano /etc/mongod.conf

• Restart mongoDB server:

sudo service mongod restart

• connect to your instance:

security:
  authorization: enabled

Start/Stop/Restart MongoDB

sudo service mongod start | stop | restart

Verify that MongoDB has started successfully

Verify that the mongod process has started successfully by checking the contents of the log file at /var/log/mongodb/mongod.log for a line reading

[initandlisten] waiting for connections on port <port>

Guides

Enable authentication
Getting Started
Before deploying MongoDB in a production environment
Manage user accounts and roles

Data directories

/var/log/mongodb
/var/lib/mongodb

Create Database

use DATABASE_NAME

Show databases

show dbs
db.adminCommand('listDatabases')
db.getMongo().getDBNames()

• To view databases they must have data
  

To show the current database type:

db

Insert

db.COLLECTION_NAME.insert({"name":"data1"})

Get Colection Names

db.getCollectionNames()

Query

db.COLLECTION_NAME.find()
db.COLLECTION_NAME.find({"name": "data1"})

RDBMS Where Clause Equivalents in MongoDB

Operation	Syntax	Example	RDBMS Equivalent
Equality	{<key>:<value>}	db.mycol.find({"by":"tutorials point"}).pretty()	where by = 'tutorials point'
Less Than	{<key>:{$lt:<value>}}	db.mycol.find({"likes":{$lt:50}}).pretty()	where likes < 50
Less Than Equals	{<key>:{$lte:<value>}}	db.mycol.find({"likes":{$lte:50}}).pretty()	where likes <= 50
Greater Than	{<key>:{$gt:<value>}}	db.mycol.find({"likes":{$gt:50}}).pretty()	where likes > 50
Greater Than Equals	{<key>:{$gte:<value>}}	db.mycol.find({"likes":{$gte:50}}).pretty()	where likes >= 50
Not Equals	{<key>:{$ne:<value>}}	db.mycol.find({"likes":{$ne:50}}).pretty()	where likes != 50

AND / OR Example:
Likes greater than 100 and whose title is either 'MongoDB Overview' or by is 'tutorials point'.
Equivalent sql where clause is 'where likes>10 AND (by = 'tutorials point' OR title = 'MongoDB Overview')'

db.mycol.find({"likes": {$gt:10}, $or: [{"by": "tutorials point"}, {"title": "MongoDB Overview"}]}).pretty()

Security

To enable Client Access Control follow this steps:

1. Start the mongod service if not already running

   sudo service mongod start
   or if runnig mongo directly:
   mongod --port 27017 --dbpath /data/db1

2. Connect to the mongo instance without access control

   mongo --port 27017

3. Create the user administrator

   use admin
   db.createUser(
   {
   user: "myUserAdmin",
   pwd: "abc123",
   roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
   }
   )

4. Edit /etc/mongod.conf, add:

   security:
   authorization: enabled

5. Restart mongo service

    sudo service mongod restart

6. Connect to the mongo instance as the administrator:

   mongo --port 27017 -u "myUserAdmin" -p "abc123" --authenticationDatabase "admin"

7. Create Additional users as needed. Example:

   use reporting
   db.createUser(
   {
   user: "reportsUser",
   pwd: "12345678",
   roles: [
   { role: "read", db: "reporting" },
   { role: "read", db: "products" },
   { role: "read", db: "sales" },
   { role: "readWrite", db: "accounts" }
   ]
   }
   )