Are Rails and Django communities re-inventing the wheel?(intosimple.blogspot.in)
intosimple.blogspot.in
Are Rails and Django communities re-inventing the wheel?
http://intosimple.blogspot.in/2012/12/rails-in-re-inventing-wheel.html
10 comments
Yes! I work for a commercial mathematics company that does OR consulting. We deliver our tools to our customers via SaaS and the user base is basically nothing in comparison to what I have scaled for in the past. The biggest problem we have is writing maintainable code at speed, performance is only a concern on a UX side and is easy to manage.
Not everyone is on the same growth path.
Not everyone is on the same growth path.
> Models are intended to serve only as an abstraction to the database.
> They are meant to be 'models of data'.
TL;DR: MVC Model is Logical model - business object (invoice) with business logic (delete_line_item), Rails Model is Physical model - persistence layer for RDBMS (add, update, delete, find rows).
In all but the most trivial applications, the latter assertion contradicts the former, and the former, is just outright wrong.
In MVC, Models are meant to model the logical objects of the system. An invoice is an object one which one acts. It is probably composed of several other objects (header, line items, addresses, etc.) which may in turn be composed of other objects.
Only the most trivial application have a one-to-one mapping from RDBMS rows to objects, which is what the OP asserts.
One does not write one's Models with the persistence layer in mind, one writes them with the business logic in mind.
So to me, this is where Rails gets the name Model wrong. The untrained, just starting out with rails learn that business logic goes in the model, so there is goes. But add_address() has no business living int he rails Model file for the invoice header, because that model is meant to be dedicated to manipulating invoice_header records in our RDBMS.
TL;DR: MVC Model is Logical model - business object (invoice) with business logic (delete_line_item), Rails Model is Physical model - persistence layer for RDBMS (add, update, delete, find rows).
In all but the most trivial applications, the latter assertion contradicts the former, and the former, is just outright wrong.
In MVC, Models are meant to model the logical objects of the system. An invoice is an object one which one acts. It is probably composed of several other objects (header, line items, addresses, etc.) which may in turn be composed of other objects.
Only the most trivial application have a one-to-one mapping from RDBMS rows to objects, which is what the OP asserts.
One does not write one's Models with the persistence layer in mind, one writes them with the business logic in mind.
So to me, this is where Rails gets the name Model wrong. The untrained, just starting out with rails learn that business logic goes in the model, so there is goes. But add_address() has no business living int he rails Model file for the invoice header, because that model is meant to be dedicated to manipulating invoice_header records in our RDBMS.
mew , we all lived the Java/JEE nightmare , and pragmatic programmers got us out of that mess, with no desire to go back to that stuff. I'll take ruby/active record flaws over the "bloated and unecessary entreprise pattern" code anytime.
It might not be wise to go back to bloated JEE. However, it would certainly be unwise to leave the knowledge behind. People working in Rails and Django applications need to learn those important lessons. It can save them from a lot of common pitfalls. I have seen people using a large number of servers for Rails applications while similar load is handled by less half their number of servers using Java.
How did J2EE become a night mare. It was pretty clear to me that you put your business logic in session beans, and they manipulated entity beans along the way.
I think that the most important idea may be in the title.
Yes, every new platform or framework reinvents the wheel, because they are almost all designed to do basically the same things, like CRUD.
I think the only way to avoid reinventing the wheel is to to adopt a common machine-processable abstraction that is at a higher level than the language and domain and use that to build the language and platform. Some type of knowledge representation maybe. Of course I'm not suggesting that is an easy thing to do.
http://en.wikipedia.org/wiki/Knowledge_representation_and_re...
Yes, every new platform or framework reinvents the wheel, because they are almost all designed to do basically the same things, like CRUD.
I think the only way to avoid reinventing the wheel is to to adopt a common machine-processable abstraction that is at a higher level than the language and domain and use that to build the language and platform. Some type of knowledge representation maybe. Of course I'm not suggesting that is an easy thing to do.
http://en.wikipedia.org/wiki/Knowledge_representation_and_re...
"Models are intended to serve only as an abstraction to the database"
I'm really tired of hearing this unqualified argument. Fat models is not a creed. It's a practical and natural design choice that we've made because it fits real world workflows best. Do you really want to be copy/pasting your order total calculation logic into 5 separate controller actions? Obviously not. And fat models doesn't mean 800 line source files. On reasonably sized Rails applications the logic gets bundled into nicely organized and maintainable concerns.
I'm really tired of hearing this unqualified argument. Fat models is not a creed. It's a practical and natural design choice that we've made because it fits real world workflows best. Do you really want to be copy/pasting your order total calculation logic into 5 separate controller actions? Obviously not. And fat models doesn't mean 800 line source files. On reasonably sized Rails applications the logic gets bundled into nicely organized and maintainable concerns.
I am not against fat models. However, the point of separating code into tiers makes it cleaner. The author does approve of concerns. His point is models are becoming too fat over time and people need to follow techniques like concerns and use cases to take out business logic. Essentially something already well known in other platforms is unknown in these communities.
I've been thinking the same thing recently, what with the debates about where logic goes in Rails apps (was here on HN a few days ago), and the debates about concerns etc. that I've seen on Rails oriented blogs and twitter accounts. I'm a .NET developer that has always admired rails (and dabbled in it a bit myself), but I have to say in .NET land these are all solved problems, and everybody just gets on with building their apps.
Seems to be missing the obvious; ruby and python (with some framework sugar) will mostly allow you there quicker than writing java with its framework sugar. I guess the trade off is rather quick to write as opposed to quick to execute. Interestingly, i also hear my colleagues say this about C and Java. Seems to be a recurring question of human understanding vs machine, no?
Wow. I am interested to know how C is reinventing the wheel. Do tell us more about it.
I think he's saying Java is recreating what C made.I don't agree since Java allows writing of code at a higher level. (with a garbage collector etc)
Every programming language sort of recreates the basics. They are the basics after all. The neat programming languages/frameworks are the ones that 'reinvent' something. Do something in a completely new way. On a programminglanguage-level it's difficult. A lot of the practices were already invented in early languages like lisp, eifel & smalltalk.
I like Ruby because it's not ashamed of taking the great parts from other programming languages and putting it together in an easily understandable language.
Every programming language sort of recreates the basics. They are the basics after all. The neat programming languages/frameworks are the ones that 'reinvent' something. Do something in a completely new way. On a programminglanguage-level it's difficult. A lot of the practices were already invented in early languages like lisp, eifel & smalltalk.
I like Ruby because it's not ashamed of taking the great parts from other programming languages and putting it together in an easily understandable language.
Nope, i'm saying is that the more you abstract and take out of the way of the coder, the quicker they can write code. Java did this to C type languages, and people got quicker. Ruby and python did this to Java. But the inverse im often told by my C colleagues is that the abstraction means you fundamentally lose control of performance. I don't agree with this statement, but what I do agree with is that if you want high level, human oriented lprogramming languages that you can quickly write code in, you need to solve very similar problems
Possibly, but like most technology there's is a set compromises you're willing to make. Rails and Django seem to be focused on getting something up and running ASAP and then dealing with whatever scaling issues you're going to have when you know exactly what they're going to be. Face it, a good amount of webapps out there won't need to be sharded. 37Signals just threw hardware at basecamp for a while (they still do?). Instagram made a few tweaks to django once they started growing rapidly, same with Disqus and i'm going to assume Pinterest did something similar as well. I would focus on the product rather than how to scale it in the early on. Once you hit the point of "How am I going to deliver this product to a group a users an order of magnitude high than I am right now" you'll hopefully have good test coverage and be able to make the right choice among sharding/read-slaves/better caching with the metrics you're able to collect.
I agree, if you dont have a product up and running at first place, how your non existence app scales doesnt matter.
"Django, the most advanced Python framework for web applications is yet to come at par with it."
In what ways is Django sub-par compared to Rails?
In what ways is Django sub-par compared to Rails?
The latest Java/Spring/JEE platforms are much more lightweight than they were 5 years ago. Look at annotated JAX-RS and you'll be amazed. You defectors should really give it a objective try. Nowadays us Java guys can focus on building our applications because our frameworks and APIs are so mature.
"Models are intended to serve only as an abstraction to the database. They are meant to be 'models of data'."
It's about Ruby or common? Because I'm sure Models could have 0 code of working with database and business-logic only. It depends on architecture of project.
It's about Ruby or common? Because I'm sure Models could have 0 code of working with database and business-logic only. It depends on architecture of project.
Model classes in Rails inherit ActiveRecord::Base. So, you can call a class method like update_all which is equivalent to an update statement on the table.
'Models could have 0 code of working with database and business-logic only' Well the business logic creeping in is one of the issues here. That is why there are attempts to separate out the business logic as in case of the use of /app/use_cases [refer to the link of use cases in the article].
'Models could have 0 code of working with database and business-logic only' Well the business logic creeping in is one of the issues here. That is why there are attempts to separate out the business logic as in case of the use of /app/use_cases [refer to the link of use cases in the article].
There's nothing forcing your model classes to inherit ActiveRecord::Base. It's perfectly acceptable to use other ORMs or even bare Ruby classes as models. If the only thing you want to do is database operations, ORM is a waste of time anyway.
"Not everyone is solving a scaling problem.
Django and Rails solve a problem that you can argue is much more common: writing concise yet readable code without needing reams of boilerplate to handle common cases."