Stored Procedures and Rails – Part 1

3 12 2007


There is no documentation in Rails about how to use stored procedures or atleast it is difficult to find where to look at. And according to DHH stored procedures is not the Rails Way to do things. DHH mentioned in his post

I want a single layer of cleverness: My domain model. Object-orientation is all about encapsulating clever. Letting it sieve half ways through to the database is a terrible violation of those fine intentions. And I want no part of it.

I somewhat agree to what DHH has to say. And that’s all fine but what if we don’t have any other option apart from using stored procedure and our stored procedure has some complex logic which we don’t want to put in our Ruby code then here is a little hack to it

ActiveRecord::Base.connection.execute("execute procedure_name")

But the above line will not return anything it will only execute your procedure, considering everything went OK.

Moreover, it’s not DRY if everytime you have to write that line of code just to call a procedure.

Here is a better way to do it:

1) Create a class and let’s call it

Class CallStoredProcedures
  your methods here .......
end

2) Create a class method within it

def self.fetch_db_records(proc_name_with_parameters)
  ActiveRecord::Base.connection.execute(proc_name_with_parameters)
end

Then simply call it as

CallStoredProcedures.fetch_db_records("exec procedure_name 'args1', 'args2', 'and so on' ")

Now you might say, that this will only execute a procedure (as I mentioned above) what if I want to return records or values from stored procedures. Then I will prefer class methods and this is how I would do it,

class CallStoredProcedures < ActiveRecord::Base

  def self.fetch_db_records(proc_name_with_parameters)
    connection.select_all(proc_name_with_parameters)
  end

  def self.insert_update_delete_calculate(proc_name_with_parameters)
    connection.execute(proc_name_with_parameters)
  end

  def self.fetch_val_from_sp(proc_name_with_parameters)
    connection.select_value(proc_name_with_parameters)
  end

end

And then simply call it like

CallStoredProcedures.method_name("exec procedure_name 'args1', 'args2', 'and so on' ")

Sweet…

If you know a better way to do it then I would love to know your views.

Stored Procedures and Rails – Part 2


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5 responses

26 03 2008
Nicholaslm

favorited this one, brother

31 07 2008
Do I need Stored Procedures? Maybe or Maybe not. « class Nasir < Jamal

[...] Maybe or Maybe not. 31 07 2008 I have written a couple of posts about 7-8 months back (here and here) on how to call stored procedures from a rails application. After using stored procedures [...]

16 09 2008
Stored Procedures in Ruby on Rails « Anand M Muranal

[...] More information click [...]

13 02 2009
Ric

Some good ideas here. Thanks.

13 05 2009
Sofija

Thank you! It is a really great to be able to find some solution when there is no core solution.

Anyway, for RoR to be able to be an enterprise class programming language and framework using stored procedures and views in an database should be part of core.
I’m not sure if there are RoR developers that are aware that procedures are best way to implement database logic, except for maybe some trivial models. That’s why I believe using stored procedures should be supported by core ActiveRecord and defined per each available datrabase adapter to support different usages. One ExecProc! should do it…
Also did anyone notice availability explicit of START TRANSACTION END TRANSACTION implementations? These are like crucial for any serious developement.

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