This document discusses using PostgreSQL as the database for Rails applications. It covers several PostgreSQL features like advanced data types (JSON, arrays, hstore), UUIDs, full text search, indexes, and PostGIS for geospatial data. Examples are provided for implementing JSON, arrays, hstore, range types like daterange and int4range, and network data types in a Rails application using PostgreSQL. Gems for full text search and database insights are also mentioned.

1. Powering Rails
Application with
PostgreSQL
Nidhi Sarvaiya

2. Who am I?
➢ Developer at Icicle technologies from last 7
years.
➢ Ruby/Ruby on Rails developer since 2009
➢ Official Handle @ice_on_rails
➢ Personal Handle @sarvaiya_nidhi

3. What Are We Covering Today?
➢ Why PostgreSQL
➢ Advance Inbuilt Data Types
➢ UUID
➢ Full Text Search
➢ Indexes
➢ Third Party Gems

4. Why PostgreSQL?
➢ First stable version was 6.0
released in 1996
➢ Latest stable version 9.3.5
➢ Fast and reliable
➢ Free, community support

5. Rails 4 Handshakes with PostgreSQL
➢ As of Rails 4, many
PostgreSQL features
are supported out of box
by Active Record

6. Built In Data Types
➢ JSON
➢ Arrays
➢ hstore
➢ Range Types
➢ PostGis
➢ Network Types

7. JSON
Scenario
Storing different social media information in your Rails
Application.
Traditional Approach
Each social media sites returns different type of information
so we usually go for NoSQL database
Alternative
Store data in JSON format in PostgreSQL

8. JSON Implementation
Migration
create_table :socials do |t|
t.json 'profile'
end
Querying
Social.first.profile['name'] => nidhi
Social.select(“profile”)
Sample Twitter JSON
{
“username” :“sarvaiya_nidhi”,
“name”:”nidhi”,
“followers”:80
}

9. Array
Scenario
Need to add multiple tags and ratings for Book
Traditional Approach
Add Separate table and map it with Book
Alternative
Add array field in Book table to map multiple tags and
ratings

10. Array Implementation
Migration
create_table :books do |t|
t.string :title
t.string :tags, array: true
end
Querying
Get Books with specific tag
Book.where("’fiction’ = ANY (tags)")
Get Books with all tags or multiple tags
Book.where("’fiction’ = ALL (tags)")
Book.where("tags @> ARRAY[?]::varchar[]",
["fantasy", "fiction"])
Sampe Book Data
Book 1
<Book id: 1, title: "Brave New World", tags:
["fantasy", "fiction"] >
Book 2
<Book id: 2, title: "The Hit", tags:
["suspense", "thriller"] >

11. Hstore
HStore is a key value store within Postgres.
Scenario
Need to apply different configuration for different clients
Traditional Approach
Maintain multiple entries in settings table by adding
Key/Value details for each client
Alternative
Use Hstore to maintain all setting for client in single record

12. HStore Implementation
Migration
def self.up
execute "CREATE EXTENSION hstore"
end
create_table :clients do |t|
t.hstore 'settings'
end
Querying
client = Client.first
client.settings # => { "background-color" => "blue",
“font-size”:”14px" }
Get Specific value - client.settings["-background-color"]
= "blue"
Sample Hstore Data
settings: { "background-color" =>
"blue",
“font-size”:”14px" }

13. Range Types
➢ daterange
➢ int4range
➢ int8range
➢numrange
➢ tsrange
➢ tstzrange
Let’s look at some of the them with example ->

14. Range Type - daterange
Scenario
Implement functionality of booking hotels room for specific
duration
Traditional Approach
Need to maintain two different fields capturing start date
and end date for booking duration
Alternative
Use daterange data type to store duration details

15. daterange Implementation
Migration
create_table :rooms do |t|
t.daterange 'duration'
end
Querying
All Events on a given date:
Room.where("duration @> ?::date",
Date.new(2014, 8, 14))
Sample Data
Room1
10/08/2014 - 14/08/2014
Room1
16/08/2014 - 21/08/2014

16. Range Type - int4range
Scenario
Implement functionality of capturing weather forecast
Traditional Approach
Need to maintain two different fields capturing high and low
temperature details
Alternative
Use int4range data type to store temperature details

17. int4range Implementation
Migration
create_table :forecasts do |t|
t.string :city
t.int4range :hi_lo
end
Querying
Forecast.create!(city: “mumbai”, hi_lo:
29..32)
Forecast.first.hi..lo => 29..32
Sample Data
Mumbai: 29..32
Delhi: 31..24

18. PostGis
➢ Geospatial extension to Postgres
➢Support for Geographic objects
➢New data types
➢Functions to work with those data types
➢ Spatial Index Support

19. Setup & Configuration
➢ Installing Postgis
➢ Add gems to support postgis with Active Record
○ activerecord-postgis-adaptor
○ rgeo
➢ Add postgis adaptor in database.yml
Reference
http://daniel-azuma.com/articles/georails

20. Postgis Data Types
➢ geometry - Any geometric type
➢ point - Point data
➢ line_string - LineString data
➢ polygon - Polygon data
➢ geometry_collection - Any collection type
➢ multi_point - A collection of Points
➢ multi_line_string - A collection of LineStrings
➢ multi_polygon - A collection of Polygons

21. Network DataType
➢ PostgreSQL comes with column types exclusively for IPv4, IPv6,
and MAC addresses.
➢ Active Record datatypes - inet, cidr and macaddre
Migration
create_table :network_addresses do |t|
t.inet :inet_address
t.cidr :cidr_address
t.macaddr :mac_address
end

22. UUID (Universally Unique Identifier)
➢ Most of the applications now have API, so use UUID rather than
integer for the ids
➢ The uuid column type represents a universally unique identifier
(UUID), a 128-bit value that is generated by an algorithm that
makes it highly unlikely that the same value can be generated
twice.
➢ Sharding would be easier. Even re-merging all the data into a
single database, if that's something you need at some point.

23. UUID ImplementaTion
Enabling UUID Support
def change
enable_extension 'uuid-ossp'
end
Migration
create_table :users, id: false do |t|
t.primary_key :id, :uuid
end
or
create_table :revisions do |t|
t.column :identifier, :uuid
end

24. Full Text Search
➢ Since PostgreSQL 8.3
➢ TSVECTOR to represent text data
➢ TSQUERY to represent search predicates
➢ Use pg_search gem for Rails application

25. Indexes Support in PostgreSQL
➢B-Tree Indexes
○ Unique Index
○ Sorted Index
○ Partial Indexes
➢ Functional Indexes
➢ Multi Column Indexes
➢ GIST & GIN indexes

26. Gems
➢ Full Text Search Gem
○ pg_search - https://github.com/Casecommons/pg_search
➢Database Insight
○ pghero - https://github.com/ankane/pghero
➢ Postgres Extensions
○ postgres_ext - https://github.com/dockyard/postgres_ext

27. References
http://edgeguides.rubyonrails.org/active_record
_postgresql.html
http://www.informit.com/articles/article.aspx?p=
2220311&seqNum=13

28. THANK
YOU