Magma counseling

Ramiro Diaz Trepat ramiro at novamens.com
Thu Jul 1 17:23:14 UTC 2004


Thank you very much guys.
Marco, I know GOODS is an excellent oodb, it's been used in my company 
with great success (in a C++ comertial project). 
Since I am coding squeak mostly for fun, I wanted to try the *pure* 
squeak way, and hence I wanted to give Magma a fair chance.  Besides,  I 
have an "irrational" belief in it (by now at least), and respect for the 
impressive undertaking that Chris Müller faced.  So before I give up on 
it, I want to test it more thoroughly and hear more oppinons of people 
using it, there must be more out there...

So... another important question: 
Does Magma support bidirectional relations?
I have a very simple situation where it all hangs.  Is a very simple 
line, that commits a class which holds a collection of elements that 
also have a reference to the main class.  Its so simple that I can't 
find any other explanation.
Thanks again.


r.





-- 
Ramiro Díaz Trepat
http://novamens.com
http://neosmt.com


goran.krampe at bluefish.se wrote:

>Hi!
>
>Marco Paga <seaside at marco-paga.de> wrote:
>  
>
>>I had problems with Magma too. I switched to goods OO database and it's really 
>>working without any problems. You just read some examples and you can start 
>>using it.
>>    
>>
>
>Nothing wrong with GOODs of course, I played with it a bit and Jonas
>here is actually migrating a Hibernate app over to GOODs - will be very
>interesting to see the results, especially compared to Hibernate which
>people are so excessively worked up about. ;)
>
>But I have also used Magma, and I have had almost no problems.
>
>  
>
>>Am Mittwoch, 30. Juni 2004 16:53 schrieb Ramiro Diaz Trepat:
>>    
>>
>>>Does anybody have a more detailed guide or code examples on using Magma
>>>than what is on the main Squeak Swiki?
>>>      
>>>
>
>Eh, no. :) But I am making a demo app that uses Magma. Though I am not
>sure when it will be ready for "consumption".
>
>  
>
>>>I am running into problems, at a very eary stage, and I am almost sure
>>>that these problems are caused because of my meager knowledge on how to
>>>use the framework.
>>>For example, all the collections held as attributes by classes that you
>>>intend to persist should be MagmaCollections?
>>>      
>>>
>
>No, that is not needed. You can use MagmaCollections if you want the
>features they give though. I haven't used them yet.
>
>  
>
>>>How does the fact of using Magma affect the code and development
>>>process?  What are the most important things to keep in mind?
>>>      
>>>
>
>Well, since I haven't done a lot with Magma yet - but I do have some
>experience with OOdbs in general. Object migration is likely the most
>"tricky" part. Which means the problem of migrating you old objects over
>to new evolved classes. I haven't seen exactly what limitations Magma
>has in that respect - though I think it can handle some cases.
>
>A general technique that might be useful though is if you have an
>import/export format of some kind that will not evolve. One system I
>built needed XML import/export for a large sub part of the domain model.
>We used that feature to be able to "reload" test data into an empty db
>during development.
>
>So in short - having a test db that can be recreated from either
>external files of from "instantiation code" can be a real time saver
>during development. Then the problem of object migration will not rear
>its ugly head until after the first deployment. :)
>
>Note: The above technique is not specific for OOdbs, IMHO it applies
>equally well to any system with persistent data.
>
>Finally - the development process with Magma is IMHO more or less like
>pretending you are only working in RAM. :) You just sprinkle your
>application code (NOT your domain model) with some suitable
>begin/commits.
>
>regards, Göran
>
>  
>

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