TABLE OF CONTENTS (HIDE)

MongoDB Get Started

 

Introduction

MongoDB (@ https://www.mongodb.com/) is one of the most popular NoSQL databases. It is document-oriented, and stores in BSON (Binary JSON).

"MongoDB is a general purpose, document-based, distributed database built for modern application developers and for the cloud era. No database makes you more productive."

[TODO] client-server diagram. Database organization - like MySQL.

Installation

To install mongoDB:

1. Goto https://www.mongodb.com/ ⇒ "Software" ⇒ "Community Server" ⇒
   1. (For Windows) In OS, select "Windows x64" ⇒ In Package, select "ZIP" ⇒ "Download" (e.g., "mongodb-win32-x86_64-2012plus-4.2.3.zip", 312KB) ⇒ UNZIP into a directory of your choice ⇒ Add the "bin" sub-directory into PATH (see "How to add a directory to the PATH").
   2. (For macOS)
   3. (For Ubuntu)

The "bin" sub-directory contains all the executables and tools:

• mongod: for starting mongoDB server (with suffix 'd' for daemon or server)
• mongo: for starting a command-line client
• mongoimport, monoexport:
• mongodump, mongorestore:

Getting Started

1. First, create a data directory for mongo, say "c:/mongo/data".
2. Start a CMD/Terminal/BashShell. Launch mongoDB server by running "mongod.exe", where the suffix 'd' denotes daemon (i.e., server). Observe the console message.

   mongod --dbpath "c:/mongo/data"
   ......
   2020-03-06T23:24:13.298-0700 I  NETWORK  [listener] Listening on 127.0.0.1
   2020-03-06T23:24:13.300-0700 I  NETWORK  [listener] waiting for connections on port 27017
   ......

3. Start "another" CMD/Terminal/BashShell. Launch the command-line client by running "mongo.exe" (without the suffix 'd' for client).

   mongo
   MongoDB shell version v4.2.3
   connecting to: mongodb://127.0.0.1:27017/?compressors=disabled&gssapiServiceName=mongodb
   ......
   > help
   show dbs                     show database names
   show collections             show collections in current database
   show users                   show users in current database
   show profile                 show most recent system.profile entries with time >= 1ms
   show logs                    show the accessible logger names
   show log [name]              prints out the last segment of log in memory, 'global' is default
   use <db_name>                set current database
   db.foo.find()                list objects in collection foo
   db.foo.find( { a : 1 } )     list objects in foo where a == 1
   it                           result of the last line evaluated; use to further iterate
   DBQuery.shellBatchSize = x   set default number of items to display on shell
   exit                         quit the mongo shell
   
   // show databases
   > show dbs
   admin   0.000GB
   config  0.000GB
   local   0.000GB
   
   // show collections (documents)
   > show collections
   
   // Create a database called "coffeeshopdb"
   // Database will be created when you create the first collection
   > use coffeeshopdb
   switched to db coffeeshopdb
   
   // Create a collection (document)
   > db.createCollection("beverage")
   { "ok" : 1 }
   
   > show dbs
   admin         0.000GB
   coffeeshopdb  0.000GB
   config        0.000GB
   local         0.000GB
   > show collections
   beverage
   
   // Insert one row
   > db.beverage.insert({ id: 1, name: 'Espresso', price: 5.5 })
   WriteResult({ "nInserted" : 1 })
   
   // Insert multiple rows as an array
   > db.beverage.insert([
         { id: 2, name: 'Cappuccino', price: 5.6 },
         { id: 3, name: 'Latte', price: 5.7 }
       ])
   BulkWriteResult({
     "writeErrors" : [ ],
     "writeConcernErrors" : [ ],
     "nInserted" : 2,
     "nUpserted" : 0,
     "nMatched" : 0,
     "nModified" : 0,
     "nRemoved" : 0,
     "upserted" : [ ]
   })
   
   // Query (or Find)
   > db.beverage.find().pretty()
   {
     "_id" : ObjectId("5e63453cd24e043c085e1014"),
     "id" : 1,
     "name" : "Espresso",
     "price" : 5.5
   }
   {
     "_id" : ObjectId("5e63461cd24e043c085e1015"),
     "id" : 2,
     "name" : "Cappuccino",
     "price" : 5.6
   }
   {
     "_id" : ObjectId("5e63461cd24e043c085e1016"),
     "id" : 3,
     "name" : "Latte",
     "price" : 5.7
   }
   
   // Find with filter
   > db.beverage.find({ id : 3 }).pretty()
   {
     "_id" : ObjectId("5e63461cd24e043c085e1016"),
     "id" : 3,
     "name" : "Latte",
     "price" : 5.7
   }
   
   // Update with $set
   > db.beverage.update({ name: 'Latte' }, { $set: { name: 'Latte New' }})
   WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
   > db.beverage.find({ id: 3 } ).pretty()
   {
     "_id" : ObjectId("5e63461cd24e043c085e1016"),
     "id" : 3,
     "name" : "Latte New",
     "price" : 5.7
   }
   
   // Update with $inc
   > db.beverage.update({ name: 'Latte New' }, { $inc: { price: -1.1 } })
   WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
   > db.beverage.find({ id: 3 }).pretty()
   {
     "_id" : ObjectId("5e63461cd24e043c085e1016"),
     "id" : 3,
     "name" : "Latte New",
     "price" : 4.6
   }
   
   // Update with $mul
   > db.beverage.update({ name: { $in: ['Espresso', 'Cappuccino'] } }, { $mul: { price: 1.2 }})
   WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })
   > db.beverage.find({ id: { $in: [1, 2] } }).pretty()
   {
     "_id" : ObjectId("5e63453cd24e043c085e1014"),
     "id" : 1,
     "name" : "Espresso",
     "price" : 6.6
   }
   {
     "_id" : ObjectId("5e63461cd24e043c085e1015"),
     "id" : 2,
     "name" : "Cappuccino",
     "price" : 5.6
   }
   
   > exit
   bye

[TODO] mongoimport: Import from JSON, CSV files

[TODO] graphical client, Studio 3T @ https://robomongo.org/

 

 

REFERENCES & RESOURCES

Latest version tested: MongoDB v4.2.3
Last modified: March, 2020