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NoSQL

Mike Calvo

mike@citronellasoftware.com

Case Against Relational Data

• Transactional behavior may be too slow for extreme volumes
• Data models a document more than relationships
• Dynamic, frequently changing data structures
• Tree and graph structures require too much joining to be feasible

Types of NoSQL Data Stores

• Key-value store
• Document store
• Graph database
• Column database

Key-value Store

• Examples: Redis, Memcached, Couchbase
• Good for:
  • Persistent hash tables
  • Session tokens
  • Global state
  • Counters

Document-oriented Store

• Examples: MongoDB, CouchDB, Couchbase
• Good for:
  • User profile data
  • Questionnaire data
  • Retail product data

Graph Database

• Examples: Neo4J, OrientDB
• Good for:
  • Social network graphs
  • Directory and tree structures

Column Database

• Examples: HBase, Cassandra, Bigtable
• Good for:
  • Random realtime read/write access to large data sets
  • Time series data

Closer Look: MongoDB

• Database is a set of collections
  • Conceptually similar to tables
• Each collection holds a set of documents
  • Conceptually similar to rows
• Documents are stored as binary JSON (BSON)
• Each document has an Id property for fast lookup

Example MongoDB Document

{
  "_id": ObjectId("5248d92ae102251e9e94eb4b"),
  "title": "With or Without You",
  "releaseYear": 1987,
  "artist": {
    "name": "U2"
  }
}

MongoDB Features

• Scalability
  • Clustering
  • Sharding
• Files and binary data support
• Extensive cloud support (hosting)
• Command-line interactive shell

MongoDB Cloud Support

• Many options exist for Mongo SAAS providers
• Reduce the need to fully understand complex administration
• Popular options:
  • MongoLab (free developer instance)
  • MongoHQ
  • ObjectRocket

Install MongoDB Locally

• http://www.mongodb.org/downloads
  • Unzip
  • Add the mongo/bin directory to your path
• Mac: brew install mongodb
• Interactive shell: mongo <instance> -u user -p password

Simple Mongo Commands

• Insert a record: db.artists.insert({name: "U2"})
• Get the size of a collection: db.artists.count()
• Query the collection: db.artist.find({name: "U2"})

Setup MongoLab Instance

• Let’s setup a new developer instance at MongoLab and use the interactive console to connect to it

Enabling Mongo in Spring Boot

https://spring.io/guides/gs/accessing-data-mongodb/

• Gradle Dependency: compile("org.springframework.boot:spring-boot-starter-data-mongodb")

Mongo Repositories

• MongoRepository

import org.bson.types.ObjectId
import org.springframework.data.mongodb.repository.MongoRepository

interface ReviewNoteRepository extends MongoRepository<ReviewNote, ObjectId> {
  List<ReviewNote> findByRelease(Release release)
}

Mapping Classes to Mongo Collections

• Use @Document to mark a class as persist-able to Mongo
• Use @Id to mark a field as the id property
• Classes can contain both @Entity and @Document

MongoDb IDs

• Does not support long integers
• Supported Types:
  • java.lang.String
  • java.math.BigInteger
  • org.bson.types.ObjectId

Mixed JPA/Mongo

• Annotate your Config class:

  @EnableJpaRepositories(basePackages = "com.acme.repositories.jpa")
  @EnableMongoRepositories(basePackages = "com.acme.repositories.mongo")
  

Configuring MongoDB

• application.properties:

# MONGODB (MongoProperties)
spring.data.mongodb.authentication-database= # Authentication database name.
spring.data.mongodb.database=test # Database name.
spring.data.mongodb.field-naming-strategy= # Fully qualified name of the FieldNamingStrategy to use.
spring.data.mongodb.grid-fs-database= # GridFS database name.
spring.data.mongodb.host=localhost # Mongo server host.
spring.data.mongodb.password= # Login password of the mongo server.
spring.data.mongodb.port=27017 # Mongo server port.
spring.data.mongodb.repositories.enabled=true # Enable Mongo repositories.
spring.data.mongodb.uri=mongodb://localhost/test # Mongo database URI. When set, host and port are ignored.
spring.data.mongodb.username= # Login user of the mongo server.

Mongo Resources

• http://mongodb.org
• GORM for Mongo:
  • http://grails.github.io/grails-data-mapping/mongodb/manual/index.html
• MongoDB: The Definitive Guide by Chodorow and Dirolf