Introducing
RavenDB
Agile Persistence in .Net

About Johnny Graber
•Software Engineer - Swiss Medical Association
•Twitter: @j_graber
•E-Mail: JG@JGraber.ch
•Blog: ImproveAndRepeat.com Examples at

Today’s Main Topics
•NoSQL
•RavenDB
•Agile Persistence

Demo RavenDB .Net Client
How simple is it to access RavenDB?

NoSQL?

No SQL

Not only SQL

Polyglot Persistence

Relational Databases aren’t
Obsolete

Great for
•Optimized Writes
•Minimal Storage Footprint
•Flexible Querying

But
•Mostly Reads in Our Applications
•Storage Costs (Almost) Nothing
•Hard to Scale

NoSQL Provides Solutions

Main Types of NoSQL
•Key / Value Store
•Graph Database
•Column Database
•Document Store

RavenDB
•2nd Generation Document Database
•Built on .Net
•Schema Free

Some RavenDB Features
•Safe by Default
•Supports Transactions (ACID)
•Best Practices Built in

A Document in RavenDB
•Self-Contained
•Independent
•Redundant Data (History)

A Document in RavenDB

Running RavenDB
•Standalone Server
•Part of Your Web-Application
•Embedded Mode

Installing RavenDB

RavenDB Studio
•Look Into the Database
•Generate Sample Data
•Administration Tools

Demo RavenDB Studio
How does the administration interface works?

Connect to RavenDB
•.Net Client
Install-Package RavenDB.Client
•HTTP API

Demo HTTP API
Can you use RavenDB without .Net?

Querying RavenDB
var books = from books in session.Query<Book>()
where books.Title.StartsWith("Raven")
select books;
var book = session.Load<Book>("books/1");

Indexes in RavenDB
•All Queries Need an Index
•Static or Dynamic
•Created in Background (Stale Index)

Challenges for Index Creation
•Schema Free Data
•Fixed Structure to Find Data
•Closing the Gap with Map/Reduce

Map/Reduce
This is probably the most
common error that
people make with any
sort of data access
technology. "Just give me
the whole thing, I'll make
sense of it on the client
side." In the RDBMS
world, this would be
expressed as "SELECT *
FROM Orders".
The problem with such
queries is they can
potentially…
Map
Reduce

Demo Index Creation
How hard can it be?

Licencing RavenDB
•AGPL for Open Source Projects
•Commercial Licence: 399$/Year/Instance
•RavenHQ: Starting at 10$/Month

Agile Persistence

Development Today
•Agile Approach
•Embrace Change
•Fail Fast

Except in the Persistence Layer
•First Time Right
•Hard to Change
•Don’t Touch

“When the Database must be
correct the first time, every part of
the application must be known at
the beginning”

“Persistence should be
an application detail”

Domain-Driven Design
•Aggregates
•Bounded Context
•Entity or Value Object

Benefits of Following DDD Principles
•History of Documents
•Complete Change Tracking
•Optimised Data Access

Command Query
Responsibility Segregation (CQRS)
•Commands Modify State
•Queries Answer Questions
•Keep Them Apart

CQRS for Fast Applications

CQRS and RavenDB
•HTTP API (REST )
•When Unauthenticated Only Allow Read
•Done

TDD and RavenDB
•Don’t Abstract an Abstraction Layer!
•Use In-Memory Mode
•It’s Fast Enough

Changing Documents
•Easily Done
•Know the Impacts
•Worst Case: Full DB Update

Demo Schema Change
How can you change your schema?

Use RavenDB
•Hacking
•Pet Projects
•Prototypes

Try This at Home
NOT in Production!

What’s Missing
•Authorisation & Authentication
•Bulk Inserts
•Paging
•Sharding

More on RavenDB
•RavenDB.net
•Tekpub.com
•ImproveAndRepeat.com

More on Polyglot Persistence
•Martin Fowler:
http://martinfowler.com/bliki/CQRS.html
•Jimmy Bogard: Real World Polyglot Persistence
http://vimeo.com/68320412

Questions?
JG@JGraber.ch

Thank You!