Re: Mongoose 0.1.1

Ruby
1

-----Original Message-----
From: Jamey C. [mailto:[email protected]]
Sent: Thursday, July 20, 2006 1:03 PM
To: ruby-talk ML
Subject: [ANN] Mongoose 0.1.1

What is Mongoose?

Mongoose is a database management system written in Ruby. It has an
ActiveRecord-like interface, uses Skiplists for its indexing, and
Marshal for its data serialization. I named it Mongoose,
because, like
Rudyard Kipling’s Rikki-Tikki-Tavi, my aim is for it to be
small, quick,
and friendly.

What does Mongoose mean in terms of the future of KirbyBase? Is
KirbyBase defunct?

Regards,

Dan

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2

Berger, Daniel wrote:

What does Mongoose mean in terms of the future of KirbyBase? Is
KirbyBase defunct?

I will continue to support and maintain KirbyBase. It is pretty mature
and stable at this point. Some of the new things I wanted to try were
going to be hard to retrofit into KirbyBase, due to it’s philosophy and
architecture.

My plan is to slowly bring Mongoose up to the same feature set as
KirbyBase. Because of its architecture, I think Mongoose has more
potential for scalability than KirbyBase.

If there is a new feature that anyone would like to see in KirbyBase, I
will definitely consider it. Or, if there is a particular feature of
KirbyBase that you would really like to see implemented in Mongoose,
please let me know.

Jamey

3

On Jul 20, 2006, at 2:21 PM, Jamey C. wrote:

My plan is to slowly bring Mongoose up to the same feature set as
KirbyBase.

Does ?hat mean Mongoose will gain a plain text output, maybe using
YAML instead of Marshal to dump?

I realize Marshal is a key element of the knew performance. I’m just
wondering if there could be an option, for those who was the easily
edited data and are willing to make the speed sacrifice.

James Edward G. II

4

James Edward G. II wrote:

edited data and are willing to make the speed sacrifice.
I think I am going to tackle this one using a two-pronged approach:

1). I will soon add #import and #export methods to the Table class, so
that if you needed to edit a table as text, you could simply #export all
of the records to a text file, edit it, then #import the text file back
into the table. I was planning on making the format CSV (taking
advantage of FasterCSV, perhaps you’ve heard of it :wink: ). Would people
prefer YAML instead? My thought with YAML was just that, with a large
table, it could quite large, since it places each field on a newline.

2). Down the road a bit, I plan on offering the option to switch off
the serialization via Marshal and just have the table stored as a
line-delimited plain-text file (just like KirbyBase). You would
definitely lose some speed, but then you could edit the table files
directly.

I would be interested in any feedback on my approach. If you would
really like to see a feature be implemented sooner, please speak up!

Jamey

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5

On Jul 20, 2006, at 3:10 PM, Jamey C. wrote:

just wondering if there could be an option, for those who was the
large, since it places each field on a newline.
Ooo, I really like this option actually. This way you keep all the
speed and can still edit as needed.

My only request would be to keep the interface to this trivial to get
at. It would be perfect if you could do something like:

ruby -r mongoose -e ‘…DUMP CODE HERE…’ > table.csv

James Edward G. II

6

Brilliant! Great direction for you to go in my opinion. Will Mongoose be
compatible with rails at some point?

7

Simon H. wrote:

Brilliant! Great direction for you to go in my opinion. Will Mongoose be
compatible with rails at some point?

Boy! I could write a book about this question! I don’t mean to be
flippant, but it all depends on what you mean by “compatible”.

Warning I am not a Rails guru (I’m not a Ruby guru, for that
matter). I’ve built a few Rails apps, but I am definitely not an
expert, especially on the internals of Rails. That being said…***

If you mean, “Will there ever be an ActiveRecord adapter for
Mongoose?”. Hmm, that’s a toughie. ActiveRecord really likes dbms’s
that use SQL and that implement the relational model. Assaph M., the
author of Pimki, actually wrote an ActiveRecord adapter for KirbyBase
for Rails 1.0, called Ackbar. He had to go through quite a few code
gyrations to map Rails SQL proclivities to KirbyBase’s query language.
It worked, but I don’t know how maintainable it was. Assaph himself
indicated that as ActiveRecord changed, if it broke Ackbar, it might be
too much trouble to maintain. And indeed, when Rails 1.1 came out, the
current version of Ackbar broke.

Now, Mongoose’s api is much more ActiveRecord-like than KirbyBase’s
interface. Would that make it easier to write an ActiveRecord adapter
for Mongoose (possible code name: Rikki :slight_smile: )? I don’t know enough
about writing ActiveRecord adapters to say. It might be an ironic
experience, since you would possibly have to go from ActiveRecord’s
interface, to some quasi-SQL translation in the guts, back to an
ActiveRecord-like api in Mongoose. Which leads me to my next point…

If you mean, “Will I be able to use Mongoose as a database backend for
Rails with reasonable success?”. Ahh, now you are on to something!
Recently, I was able to get KirbyBase functioning as a Rails back end,
simply by having my Rails models not inherit from ActiveRecord::Base.
Sure, I had to write my own #find method, etc. But it worked. I was
able to have it go all the way through the controller to the view and
show up in the scaffold-generated code. I didn’t pursue it much
further, because I would have had to write a whole ActiveRecord-like
frontend for KirbyBase in the model. Also, I noticed that the nice
error objects that are attached to your model didn’t, of course, work,
since I hadn’t subclassed ActiveRecord::Base.

But, this limited success leads me to believe that I might be much
more successful using Mongoose with Rails, because Mongoose is going to
stick very close to the ActiveRecord api. So, it might be as easy as
having your model classes subclass Mongoose::Table, instead of
ActiveRecord::Base. Things that wouldn’t work would be stuff like
migrations, I think. Also, it would be great if I could figure out how
to get the integrated errors working like the ActiveRecord stuff does.
I haven’t really looked at that.

So, to, hopefully, answer your question. I think it is very possible to
be able to use Mongoose as a Rails backend, with the probable loss of
some functionality. Who knows, maybe in the future, ActiveRecord won’t
be as tied to SQL and it will be much easier to write adapters for
non-SQL dbmss.

See I told you I could write a book about this!

Jamey

8

Hey Jamey-

I love mongoose! I'm digging around in the code now to see how

things work and one of the first things I miss when creating a new
record is the create method that takes a hash of key => value pairs
and saves a new record. So here is my first little patch for you.
this goes in the Table class:

#-----------------------------------------------------------------------

create

#-----------------------------------------------------------------------

def self.create(options={})
rec = new
options.each do |k,v|
rec.send("#{k}=", v) if self.column_names.include? k
end
rec.save
rec
end

It lets you do this:

irb(main):005:0> rec = Foo.create :title => ‘foo title’, :body =>
‘fooooo’
=> #<Foo:0x56d61c @body=“fooooo”, @id=3, @title=“foo title”>

I will have a look at the query language and see if there is

anything I can do to help. Is there anything specific that you would
like to see from ez_where that you couldn’t figure out?

Cheers-
-Ezra

9

I haven’t really looked at that.
You’ve aroused my curiosity. Had a little bit of trouble figuring out
how to use mongoose (some example code would have been nice), but the
following gets some validation going. I couldn’t get
validates_presence_of to work for some reason, but here’s
validates_numericality_of working. Putting together a
Mongoose::ActiveTable that has most of the functionality of an
activerecord doesn’t look to be that difficult. If implementations of
the rest of the methods on ActiveRecord::Base were added, you’d be able
to use validations and the other activerecord modules.

require ‘mongoose’

require ‘active_support’
require ‘active_record/base’
require ‘active_record/validations’

require ‘mongoose’

require ‘active_support’
require ‘active_record/base’
require ‘active_record/validations’

class Mongoose::ActiveTable < Mongoose::Table
RecordNotSaved = ActiveRecord::RecordNotSaved
def update_attribute(name, value)
send(name.to_s + ‘=’, value)
save
end
def new_record?
@id.nil?
end
def self.human_attribute_name(attribute_key_name) #:nodoc:
attribute_key_name.humanize
end
def save!
save || raise(RecordNotSaved)
end

def self.init_column(col_name, col_def, col_class)
super
meth = <<-END_OF_STRING
def #{col_name}_before_type_cast
#{col_name}
end
END_OF_STRING
self.class_eval(meth)
end

include ActiveRecord::Validations
end

class Monkey < Mongoose::ActiveTable
validates_numericality_of :arms
end

Mongoose::Table.db = Mongoose::Database.new(:path => ‘c:/temp/mongoose’)
unless Mongoose::Table.db.table_exists?(‘monkey’)
Mongoose::Table.db.create_table(‘monkey’) do |t|
t.add_column ‘arms’, :integer
end
end

m = Monkey.new()
m.arms = ‘2a’
m.save!

10

On Jul 20, 2006, at 11:37 PM, Daniel S. wrote:

I haven’t really looked at that.
to use validations and the other activerecord modules.

There’s example code distributed with Mongoose. (It’s actually the
same examples from KirbyBase, re written in a Mongoosian style.)

11

On 7/20/06, Jamey C. [email protected] wrote:

If there is a new feature that anyone would like to see in KirbyBase, I
will definitely consider it. Or, if there is a particular feature of
KirbyBase that you would really like to see implemented in Mongoose,
please let me know.

One of the great features of KirbyBase is that the tables are
hand-editable. I recently had the need to store an Array (and could
also
justify a Hash). Since these were missing from VALID_FIELD_TYPES, I
resorted to storing YAML. Perhaps a new feature could be:

  • adding support for Array and Hash (maybe in the form used by irb and
    pp?)

Of course, each element would have to be one of the other supported
types.
Maybe YAMLizing any other type would be conceivable. Just a thought…

  • Dimitri
12

There’s example code distributed with Mongoose. (It’s actually the
same examples from KirbyBase, re written in a Mongoosian style.)

Bah - I see now. That would have made it easier… I was looking for
rdoc with embedded examples and forgot to look for the ‘examples’
directory. I think I figured it out from the code well enough though.

13

Daniel S. wrote:

Thanks, Daniel. This is cool. I already implemented
validates_presence_of in the Table class, so that’s probably why it
didn’t work in your class.

My goal is to implement as many methods from ActiveRecord::Base as
possible. Your code gives me a great starting point for how to Mongoose
interact with ActiveRecord validations.

Jamey

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14

On 7/21/06, Logan C. [email protected] wrote:

On 7/21/06, Dimitri A. [email protected] wrote:

  • adding support for Array and Hash (maybe in the form used by irb and
    pp?)

See, I think that if you need to store an array you should transform it
into
a one-to-many relation. Hashes can just be a relation (id, key, value).

Ah, good point. Hadn’t thought of it that way.

Remember, a relational database is not “PStore + Searches”.

This I know. I just never considered KirbyBase to be a relational
database.
:slight_smile:

There’s always

gonna be an issue of mapping from the objects to the db. (Hence the
existence of things like ActiveRecord and Mongoose’s AR-like API.)

And Og. /me goes to improve the KirbyBase support in Og…

  • Dimitri
15

On 7/21/06, Dimitri A. [email protected] wrote:

One of the great features of KirbyBase is that the tables are

  • Dimitri
    See, I think that if you need to store an array you should transform it
    into
    a one-to-many relation. Hashes can just be a relation (id, key, value).
    Remember, a relational database is not “PStore + Searches”. There’s
    always
    gonna be an issue of mapping from the objects to the db. (Hence the
    existence of things like ActiveRecord and Mongoose’s AR-like API.)