ENIB 2015-2016 - CAI Web - S01E01- MongoDB and NoSQL

Conception d'Applications
Interactives :
Applications Web et JEE
Séance #4
Une forge JavaScript
2/4 - MongoDb and NoSQL

What's MongoDB
open-source document database
that provides high performance,
high availability,
and automatic scaling

Document database
A record in MongoDB is a document, which is a
data structure composed of field and value
pairs
Documents are similar to JSON objects

Document database
Documents are stored in collections
Collections share common indexes

Collections & documents
● No predefined schema
○ Documents in a collection can have different fields
○ Fields can be added, modified or deleted at any time
● Documents follow BSON (JSON-like) format
○ Key-value pairs (hashes)
{
"_id": ObjectId("223EBC5477A124425"),
"Last Name": "Gonzalez",

Query data
● db.collection.find()
It returns a cursor, an iterable object

RDBMS vs MongoDB
RDBMS
● Databases have tables
● Tables have rows
● Rows have cell
● Cells contain types simples
● Schemas are rigid
MongoDB
● Database have collections
● Collections have documents
● Documents have fields
● Fields contain
○ Types simples
○ Arrays
○ Other documents
● Schemas are fluid

Key features
● High performance
● High availability
● Automatic scaling

High availability
● Election at initialization or when primary lost

Installing MongoDB
1. Download MongoDB http://www.mongodb.org/downloads
2. Install the msi (win) or uncompress the tgz
(linux)
e.g. C:mongodb or /opt/mongodb
3. Create a data directory
e.g. /opt/mongodb_data or C:mongodb_data
4. Run mongo demon

Running MongoDD
horacio@horacio-xps:~$ mongod --dbpath /opt/data/
2015-05-06T23:46:14.392+0200 I JOURNAL [initandlisten] journal dir=/opt/data/journal
2015-05-06T23:46:14.394+0200 I JOURNAL [initandlisten] recover : no journal files present, no recovery needed
2015-05-06T23:46:14.431+0200 I CONTROL [initandlisten] MongoDB starting : pid=5493 port=27017 dbpath=/opt/data/ 64-bit
host=horacio-xps
2015-05-06T23:46:14.431+0200 I CONTROL [initandlisten] db version v3.0.2
2015-05-06T23:46:14.431+0200 I CONTROL [initandlisten] git version: 6201872043ecbbc0a4cc169b5482dcf385fc464f
2015-05-06T23:46:14.431+0200 I CONTROL [initandlisten] build info: Linux build6.nj1.10gen.cc 2.6.32-431.3.1.el6.x86_64 #1 SMP
Fri Jan 3 21:39:27 UTC 2014 x86_64 BOOST_LIB_VERSION=1_49
2015-05-06T23:46:14.431+0200 I CONTROL [initandlisten] allocator: tcmalloc
2015-05-06T23:46:14.431+0200 I CONTROL [initandlisten] options: { storage: { dbPath: "/opt/data/" } }
2015-05-06T23:46:14.433+0200 I STORAGE [initandlisten] info openExisting file size 16777216 but mmapv1GlobalOptions.
smallfiles=false: /opt/data/startupweekendbrest.0
2015-05-06T23:46:14.440+0200 I INDEX [initandlisten] allocating new ns file /opt/data/local.ns, filling with zeroes...
2015-05-06T23:46:14.532+0200 I STORAGE [FileAllocator] allocating new datafile /opt/data/local.0, filling with zeroes...
2015-05-06T23:46:14.532+0200 I STORAGE [FileAllocator] creating directory /opt/data/_tmp
2015-05-06T23:46:14.572+0200 I STORAGE [FileAllocator] done allocating datafile /opt/data/local.0, size: 64MB, took 0.023 secs
2015-05-06T23:46:14.585+0200 I NETWORK [initandlisten] waiting for connections on port 27017

Tools in MongoDB
● mongod - primary daemon process
● mongo - command-line client
● mongostat - command-line stats summary
● mongotop - command-line performance
tracker

Connecting to a MongoDB instance
mongo --host 127.0.0.1 --port 27017
or using default parameters
mongo
● Default host: 127.0.0.1
● Default port: 27017
horacio@horacio-xps:~$ mongo
MongoDB shell version: 3.0.2

First steps
● To view available databases:
> show dbs
local 0.078GB
test 0.031GB
● To choose a database:
> use test
switched to db test

First steps
● To check what's the current database:
> db
● To get some help:
> help
● To show the collections within a database:
> show collections

Enter some data
> a = {"Last Name": "Gonzalez","First Name": "Horacio","Date of Birth": "1976-05-
05" }
{
"Last Name" : "Gonzalez",
"First Name" : "Horacio",
"Date of Birth" : "1976-05-05"
}
> db.test.insert(a)
WriteResult({ "nInserted" : 1 })
> b={"Field A": "Value A", "Field B": "Value B"}
{ "Field A" : "Value A", "Field B" : "Value B" }
> db.test.insert(b)

Query data
● Find all the elements in a collection
> db.test.find()
{ "_id" : ObjectId("554a9944b5091037c44dddcc"), "Last Name" : "Gonzalez",
"First Name" : "Horacio", "Date of Birth" : "1976-05-05" }
{ "_id" : ObjectId("554a998eb5091037c44dddcd"), "Field A" : "Value A", "Field
B" : "Value B" }

_id
● Primary key
● Automatically indexed
● Generated as an ObjectId if not provided
● Must be unique and immutable
ObjectId: Special 12 byte value unique across cluster

Using JavaScript in mongo
> for(var i=0; i<5; i++) db.test.insert({a:42, b:i})
> db.test.find()
{ "_id" : ObjectId("554a990f0ebf783b63a57776"), "Last Name" : "Gonzalez", "First
Name" : "Horacio", "Date of Birth" : "1976-05-05" }
{ "_id" : ObjectId("554a9944b5091037c44dddcc"), "Last Name" : "Gonzalez", "First
Name" : "Horacio", "Date of Birth" : "1976-05-05" }
{ "_id" : ObjectId("554a998eb5091037c44dddcd"), "Field A" : "Value A", "Field B" :
"Value B" }
{ "_id" : ObjectId("554a9c21b5091037c44dddce"), "a" : 42, "b" : 0 }
{ "_id" : ObjectId("554a9c21b5091037c44dddcf"), "a" : 42, "b" : 1 }
{ "_id" : ObjectId("554a9c21b5091037c44dddd0"), "a" : 42, "b" : 2 }

Query for specific documents
> db.test.find({"Field A": "Value A"})
{ "_id" : ObjectId("554a998eb5091037c44dddcd"), "Field A" : "Value A", "Field B" :
"Value B" }
> db.test.find({ b: { $gt: 2 } }).sort({ b: -1 })
Conditional operators:
$all, $exists, $type, $mod,
$or, $and, $not, $nor $size,
$eq, $ne, $lt, $lte, $gt, $gte, $in, $nin...

Querying with RegEx
> db.test.findOne({ "Last Name": /Gon/})
{
"_id" : ObjectId("554a990f0ebf783b63a57776"),
"Last Name" : "Gonzalez",
"First Name" : "Horacio",
"Date of Birth" : "1976-05-05"
}

Operations
> db.test.insert(record)
> db.test.find(query)[.skip(X)][.limit
(Y)]
> db.test.findOne(query)
> db.test.remove(query[,
justone=false])

Creating index
> db.test.ensureIndex({ b: 1 })
{
"createdCollectionAutomatically" : false,
"numIndexesBefore" : 1,
"numIndexesAfter" : 2,
"ok" : 1
}

Exercice 1
● Install MongoDB
● Run mongod
● Connect using mongo
● Create a collection, add some object, tests
some queries
References

Exercice 2
Model and create a collection to store the beer
data
for the Angular-Beers project
https://github.com/LostInBrittany/angular-beers
● Tests some queries

ENIB 2015-2016 - CAI Web - S01E01- MongoDB and NoSQL

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ENIB 2015-2016 - CAI Web - S01E01- MongoDB and NoSQL