I'm working on a personal website project.
I want to make my users understand their personal data on facebook, twitter etc ...
To do this, I will use Omniauth with the different API's.
But I have no idea what database I should use to store the data.
I'm actually using PostgreSQL on my rails app.
You can use any database, mysql, postgresql, sqlite etc. If you know that your data has some kind of schema, you can use any of these. If you want your app to save any kind of data, you can use any noSQL database like mongodb with mongoid or you can use hstore feature of postgresql.
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I am building an e-commerce application using spree in rails. The application uses PostgreSQL as database. I want it to be changed to MySQL. How do I achieve this?
The short answer is, you don't. I've been through three Spree migrations where we were either using legacy data, or switching databases and trust me; you want nothing to do with this.
If you don't need to take the old data with you, you should be fine just running the migrations on a fresh MySQL database. If you need the legacy data, God be with you...
Converting Spree database schema is nothing nice, and it's hard to just pull what you need out of the database since because almost every data model depends on a foreign key from another. There are dental procedures I would go through voluntarily before attempting what you are proposing. This also begs the question; why do you need to go to MySQL from Postgres?
Is it possible to use multiple couchdb databases for data in rails app while using the CouchRest Model gem? Right now in my rails app I specify the one couchDB database in config/couchdb.yml. I was wondering if it possible to have more than one couchdb databases being used by one rails app?
You might want to check out this answer - it worked for my case where I wanted a database for each user
Recommended use of couchrest model in a multi-tenant app
I want to create an website where users can create their own teaching resources, e.g. blocks of text with embedded images etc.
How should I store this in a database in rails? I've heard mongoDB is good for storing documents but I was planning on using postgresql for the user database etc. and have read that generally you shouldn't mix different types of db
I'm sure this is an obvious question but I couldn't find an answer anywhere...
Thanks,
Graham
There are several things you could do.
1. Use PostgreSQL for both the Users table and the TeachingResources table. You could simply use a content column of type text to save all the data.
2. Use PostgreSQL but use the HStore functionality to basically store a hash of objects of your choosing, this gives you more flexibility. Rails 4 will support this by default, but there is also a gem you can use.
3. Use a combination of PostgreSQL and MongoDB (or any other NoSQL solution) in your app. I don't see this as a bad solution, but it does put you outside of the "new user constraints" in Rails, so this might not be the best route to start with
4. Go NoSQL all the way. There is no reason you shouldn't be able to use MongoDB for your User model. However, you are right that this type of datastorage can not give full ACID guarantees, so be careful with product planning and know it's vulnerabilities (but also its strengths).
Can I use MongoDB and a PostgreSQL in one rails app? Specifically I will eventually want to use something like MongoHQ. So far I have failed to get this working in experimentation. And it concerns me that the MongoDB documentation specifically says I have to disable ActiveRecord. Any advice would be appreciated.
You don't need to disable ActiveRecord to use MongoDB. Check out Mongoid and just add the gem plus any models along side any of your existing ActiveRecord models. You should note that MongoHQ is just a hosting service for MongoDB and can be used alongside any Object Document Mapper (ODM).
For further details check http://mongoid.org/en/mongoid/docs/installation.html. Just skip the optional 'Getting Rid of Active Record' step.
On a recent client site I worked with a production system that merged MySQL and MongoDB data with a single Java app. To be honest, it was a nightmare. To join data between the two databases required complex Java data structures and lots of code, which is actually databases do best.
One use-case for a two database system is to have the pure transactional data in the SQL database, and the aggregate the data into MongoDB for reporting etc. In fact this had been the original plan at the client, but along the way the databases became interrelated for transactional data.
The system has become so difficult to maintain that is is planned to be scrapped and replaced with a MongoDB-only solution (using Meteor.js).
Postgres has excellent support for JSON documents via it's jsonb datatype, and it is fully supported under Rails 4.2, out of the box. I have also worked with this and I find it a breeze, and I would recommend this approach.
This allows an easy mix of SQL and NoSQL transactions, eg
select id, blast_results::json#>'{"BlastOutput2","report","results","search","hits"}'
from blast_caches
where id in
(select primer_left_blast_cache_id
from primer3_output_pairs where id in (185423,185422,185421,185420,185419) )
It doesn't offer the full MongoDB data manipulation features, but probably is enough for most needs.
Some useful links here:
http://nandovieira.com/using-postgresql-and-jsonb-with-ruby-on-rails
https://dockyard.com/blog/2014/05/27/avoid-rails-when-generating-json-responses-with-postgresql
There are also reports that it can outperform MongoDB on json:
http://www.slideshare.net/EnterpriseDB/the-nosql-way-in-postgres
Another option would be to move your Rails app entirely to MongoDB, and Rails has very good support for MongoDB.
I would not recommend running two databases, based on personal observations on how it can go bad.
I'm trying to build an app in Ruby on Rails that stores specified tweets in a database.
I think I'm going to use the Twitter gem, but I'm not sure how to go from displaying tweets to actually storing them.
Any help or resource links are greatly appreciated!
And which database would be best suited for this application?
When iterating results, you can store them in model objects, which in turn map to tables in sql databases (mysql, postgres, oracle), or documents in nosql dbs like mongodb.
Tweaking an example in the twitter gem's README:
# Find and store the 3 most recent marriage proposals to #justinbieber
Twitter::Search.new.containing("marry me").to("justinbieber").result_type("recent").per_page(3).each do |r|
MyLocalTweetModel.create!(:from_user => r.from_user, :text => #{r.text}")
end
This can be done with any database, really.
The decision over which database to use depends on many other factors, such as where your app will be hosted, what traffic you expect, how you plan to scale it... and taste is definitely one of these factors, and not an unimportant one. I hate Active Record migrations, for instance, though I like its many other niceties. Active Record is the default ORM rails uses for sql databases.
If you're new to all this, just start on a simple sqlite database with Active Record. There's more of a learning-curve to the alternatives.