MongoDB

Standardization of NoSQL databases

Portability between non-relational databases

CouchDB

PostgreSQL

AGPL license

PostgreSQL license (like the BSD license)

MySQL is GPLv2

Drizzle has rewritten their MySQL driver so it’s not GPL

Oracle’s behavior toward products they own that compete

InnoDB MySQL engine

Microsoft SQL – The price hike and bug report that drove Josh to PostgreSQL

Customer expectations vs Intended functionality

GreenPlum

Alexa

Implementing the minimum feature set and getting feedback.

Transactional DDL – All operations are transactional except create database.

Database Migrations – PostgreSQL can do migrations with no downtime.

Memcached

Redis

Solr

ElasticSearch

Foreign Data Wrappers – a driver for external data sources that can then be managed through PostgreSQL

Lucene

Hadoop HBase

Cassandra

Project Voldemort

HyperTable

Riak

Amazon Cap Theorem Papers

VoltDB

ActiveRecord models are based upon tables in relational databases. This, of course, means that they can be relational. Models can associate in three main ways: one to many, one to one, and many to many.

One to many is usually achieved by calling has_many on the model representing the “one” to state that it “has many” of its counterparts. The model that represents the “many” calls

belongs_to . Here’s an example:

class User < ActiveRecord::Base

has_many :posts

end

class Post < ActiveRecord::Base

belongs_to :user

end

In addition, the model that represents the “many” needs a reference column or foreign key for the “one”. In this case, the posts table would have a user_id column.

One to one works the same way one to many works except it uses has_one instead of has_many.

Many to many is implemented in one of two different ways. The first--and generally default--way of doing this is has_and_belongs_to_many. As you can imagine, this is used just like has_many or belongs_to except you call it in both models.

class Tag < ActiveRecord::Base

has_and_belongs_to_many :posts

end

class Post < ActiveRecord::Base

has_and_belongs_to_many :tags

end

The Rogues talk about metaprogramming in Ruby.

You can get cassandra at cassandra.apache.org and the ruby gem by running:

gem install cassandra

I did run into a problem with the trift_client gem when installing. If you get a Load Error, run this.

sudo chmod 644 /usr/local/lib/ruby/gems/1.8/gems/thrift_client-0.6.3/lib/thrift_client/*.rb

sudo chmod 755 /usr/local/lib/ruby/gems/1.8/gems/thrift_client-0.6.3/lib/thrift_client/connection

Here are some of the Cassandra commands from the video:

#connects to the cassandra server using the Twitter keyspace

store = Cassandra.new(“Twitter”)

# create a new column family in the Twitter keyspace called Users

cf_def = CassandraThrift::CfDef.new(:keyspace => “Twitter”, :name => “Users”)

store.add_column_family(cf_def)

# add or create a row to the column family

store.insert(“Users”, “cmaxw”, {“name” => “Charles Max Wood”, “description” => “Awesome coder”})

# remove a column from a row

store.remove(“Users”, “cmaxw”, “description”)

Download 17.2 MB

Download (iPod & iPhone) 20.9 MB

Take the 2011 Readers Survey

You can get cassandra at cassandra.apache.org and the ruby gem by running:

gem install cassandra

I did run into a problem with the trift_client gem when installing. If you get a Load Error, run this.

sudo chmod 644 /usr/local/lib/ruby/gems/1.8/gems/thrift_client-0.6.3/lib/thrift_client/*.rb

sudo chmod 755 /usr/local/lib/ruby/gems/1.8/gems/thrift_client-0.6.3/lib/thrift_client/connection

Here are some of the Cassandra commands from the video:

#connects to the cassandra server using the Twitter keyspace

store = Cassandra.new(“Twitter”)

# create a new column family in the Twitter keyspace called Users

cf_def = CassandraThrift::CfDef.new(:keyspace => “Twitter”, :name => “Users”)

store.add_column_family(cf_def)

# add or create a row to the column family

store.insert(“Users”, “cmaxw”, {“name” => “Charles Max Wood”, “description” => “Awesome coder”})

# remove a column from a row

store.remove(“Users”, “cmaxw”, “description”)

Download 17.2 MB

Download (iPod & iPhone) 20.9 MB

Take the 2011 Readers Survey

You can get cassandra at cassandra.apache.org and the ruby gem by running:

gem install cassandra

I did run into a problem with the trift_client gem when installing. If you get a Load Error, run this.

sudo chmod 644 /usr/local/lib/ruby/gems/1.8/gems/thrift_client-0.6.3/lib/thrift_client/*.rb

sudo chmod 755 /usr/local/lib/ruby/gems/1.8/gems/thrift_client-0.6.3/lib/thrift_client/connection

Here are some of the Cassandra commands from the video:

#connects to the cassandra server using the Twitter keyspace

store = Cassandra.new(“Twitter”)

# create a new column family in the Twitter keyspace called Users

cf_def = CassandraThrift::CfDef.new(:keyspace => “Twitter”, :name => “Users”)

store.add_column_family(cf_def)

# add or create a row to the column family

store.insert(“Users”, “cmaxw”, {“name” => “Charles Max Wood”, “description” => “Awesome coder”})

# remove a column from a row

store.remove(“Users”, “cmaxw”, “description”)

Download 17.2 MB

Download (iPod & iPhone) 20.9 MB

Take the 2011 Readers Survey

How PostgreSQL got started

Ingres

The Apache Foundation

The PostgreSQL core team and it’s role.

Data Warehousing

It’s community property like Linux

The SQL Query Language

The C Programming Language

gcc

Standardization

Google Summer of Code

XML Indexing

XPath Support

ISN/ISBN Data Type

Array Data Types

HStores (Dictionary or Hash)

Full Text Search

Tri-grams

Sphinx

Lucene

Why people switch from MySQL

Performance

Reliability

Special Features

Supports really complex queries

Worry about the future of MySQL

Skype – 200 Postgres servers

Sky tools clustering platform

Heroku

San Francisco PostgreSQL User Group

Differences between MySQL and PostgreSQL

MySQL was originally written to please web developers

Postgres was written by DBA’s

Postgres will throw out a feature they can’t stabilize

MySQL will accept a feature and then try to stabilize it

Postgres really allows you to run code inside the database

Postgres is more reliable and secure

Lowers admin cost due to better uptime

Rails was originally built around MySQL

You can get some boosts by bypassing the ORM and going directly to the database

Full JSON support is upcoming

Django

The PostgreSQL Ruby driver

ByteA binary data type

Simplified data types (Text data type)

Why people switch from PostgreSQL to MySQL

MySQL has been commercially successful longer than postgres

Vendor tools

Cheap hosting for MySQL

A lot of things are designed to work out of the box with PostgreSQL

PGSQL Novice list

Postgres Open

Postgres has a new version coming out soon (changelog)

Postgres 9.2

Multi-core support

Postgres included documentation

Beginning Databases with Postgres – Dated but gives the basics

Download (iPod & iPhone) 4.61 MB

In your Rails controllers you have filters you can place on incoming requests, outgoing responses, or wrap around your actions.

Before filters are run on requests before the request gets to the controller’s action. It can return a response itself and completely bypass the action.

The most common use of before filters is validating a user’s authentication before granting them access to the action designated to handle their request. I’ve also seen them used to load a resource from the database, check permissions on a resource, or manage redirects under other circumstances.

After filters are run after the action completes. It can modify the response. Most of the time if something is done in an after filter, it can be done in the action itself, but if there is some logic to be run after running any of a set of actions, then an after filter is a good place to do it.

Generally, I’ve seen after and around filters used for logging.

Around filters may have logic before and after the action being run. It simply yields to the action in whatever place is necessary. Note that it doesn’t need to yield to the action and may run without doing so like a before filter.

You can use around filters for exception handling, setup and teardown, and a myriad of other cases.

The Rogues discuss corporate sponsors of Open Source Software.

You can get a full list of the ActiveRecord callbacks here.

Callbacks are a handy way of insuring specific behaviors on your models as well as managing the events that follow the callbacks.

For example, a before_destroy callback can be called to destroy associated objects. (This is best done on the association with :dependent => :destroy, but it makes sense here too.)

You can also stop the destroy process if you have dependent objects you can’t destroy by returning false.

I’ve used ActiveRecord Callbacks to:

Set default values

Format specific fields (like phone numbers)

Send emails when an object is updated or deleted

Create child objects from comma delimited lists in a string

Change an object’s state