[Zope3-Users] Re: FW: ZODB storage ways

j.kartnaller j.kartnaller at robotech.at
Tue Apr 4 01:51:28 EDT 2006


Hi David.

Yesterday I implemented an integration for SQLAlchemy into zope.

Currently it contains a data manager which handles zope transactions and
a container for mapped sqlalchemy objects.

I will setup a svn repository this week.

There are some open configuration things.
I started with some ZCML configuration directives to be able to setup
the database in ZCML (not very popular these days :).

Jürgen

David Pratt wrote:
> Hi Pete. I have been looking at SQLAlchemy for Zope3. Can you advise how 
>  you are using this with zope's transactions. It seems that there are 
> some folks using SQLAlchemy with Zope3 for sure. I am hoping to see a 
> few things formalized somewhere or some work on assembling a small 
> package like SQLOS did for SQLObject. I think SQLAlchemy is a more 
> feature rich ORM and am simply looking for a way to use it in Zope3.
> 
> Regards,
> David
> 
> Pete Taylor wrote:
>> I agree with Marco that the use case i can most readily imagine for
>> needing to tie zodb objects back to an rdb is to allow people to run
>> reports or get at historical data in more conventional ways...
>>
>> I've had to make allowances for that in a number of projects i'm
>> currently working on for zope3...  this may not be immediately
>> helpful, but sqlalchemy (http://www.sqlalchemy.org) provides a really
>> nice way to simply write your classes as you would, tie the relevant
>> elements back to an rdb with a simple mapper on the class, without
>> restricting your class design too much.
>>
>> as an example, i have a BTreeContainer derivative that maps a number
>> of it's Bool, TextLine, and Date attributes to a msyql database, while
>> letting other objects it contains be treated just like any other
>> BTreeContainer.  So long as you tie the sqlalchemy's sessions in
>> correction and commit when you know the zodb will be committing, it's
>> been pretty seamless so far, for my experience.
>>
>> i admit, tables i'm using are not complex, nor are the objects that
>> are tied to them, so your mileage may vary...
>>
>> On 4/3/06, Pete Taylor <jtaylor at thig.com> wrote:
>>
>>>
>>> -----Original Message-----
>>> From: zope3-users-bounces at zope.org 
>>> [mailto:zope3-users-bounces at zope.org] On
>>> Behalf Of Marco Mariani
>>> Sent: Monday, April 03, 2006 1:14 PM
>>> To: Andreas Jung; reinhold.strobl at gmx.net; 
>>> zope3-users at zope.org
>>> Subject: Re: [Zope3-Users] ZODB storage ways
>>>
>>> Andreas Jung wrote:
>>>
>>>
>>>>> I am searching for a way to change transparently the storage of ZODB
>>>>> from file-base to a relational database. In general, Zope books
>>>>> state, that this is possible.
>>>>>
>>>>
>>>> one solution:
>>>>
>>>> <http://hathawaymix.org/Software/PGStorage>
>>>
>>> Unfortunately, pickles are not even remotely a SQL datatype... :)
>>>
>>> I guess many people just want a SQL backend to allow queries from third
>>> parties in the way they are used to.
>>>
>>> If I do NOT want to be able to modify the data via SQL, and performance
>>> is not a concern (not huge systems..), wouldn't it be better to "adapt"
>>> :-) the data structure to a DBMS backend, with sane natural keys, but
>>> without the hassle of advanced integrity constraints?
>>>
>>> After all, as Joe Celko says, a table is not a (file|class) and a row is
>>> not a (record|instance).. the structure we manipulate objects in ZODB is
>>> not always the one we would like to use to perform SQL queries.
>>>
>>> I mean, not dumping the whole ZODB on the DBMS, but run a few SQL
>>> commands whenever an object "the clerks are interested into" changes its
>>> state or data, gets deleted or whatever.
>>>
>>> This, and adding a dump function to wipe out and recreate the SQL DB
>>> should we have the need (structure changes, whatever).
>>>
>>> I've yet to look at zope events, maybe it can be done without too much
>>> effort?
>>>
>>>
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>>> Zope3-users at zope.org
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>>
>>
>>
>>
>> -- 
>> "All guilt is relative, loyalty counts, and never let your conscience
>> be your guide."
>>   - Lucas Buck, American Gothic
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>>



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