Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-14 Thread Mail List
From: Joachim Werner [EMAIL PROTECTED] This is true in the ZODB, but can be complicated by acquisition. If an object can acquire itself, it can cause issues. Plus it becomes difficult to know whether objects are clones or just identical instances, although this can be mitigated by

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-14 Thread Shane Hathaway
Joachim Werner wrote: Probably I'm daft because it is Friday night, but AFAIK ZODB and most OODB's store an object only once, keyed by its object id. The rest is just references through that oid, so objects that belong to more than one container can be added to all these containers

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-14 Thread Jeff
From: Joachim Werner [EMAIL PROTECTED] This is true in the ZODB, but can be complicated by acquisition. If an object can acquire itself, it can cause issues. Plus it becomes difficult to know whether objects are clones or just identical instances, although this can be mitigated by

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-14 Thread Juan David Ibáñez Palomar
P.S.: Shane, have you developed Symlinks any further? I think they could be extremely useful. I tried out the initial release and liked it, except for the fact that the symlinks looked EXACTLY like real ones, so they can be very irritating ... I'm not sure what to do with symlinks.

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-13 Thread Joachim Werner
This is true in the ZODB, but can be complicated by acquisition. If an object can acquire itself, it can cause issues. Plus it becomes difficult to know whether objects are clones or just identical instances, although this can be mitigated by exposing their Python instance id. Acquisition

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-13 Thread Joachim Werner
Probably I'm daft because it is Friday night, but AFAIK ZODB and most OODB's store an object only once, keyed by its object id. The rest is just references through that oid, so objects that belong to more than one container can be added to all these containers and n:m relations are

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-11 Thread Cees de Groot
Shane Hathaway [EMAIL PROTECTED] said: That's one reason ZODB is so nice. You can write an application without writing a formal schema. One of the reasons I am seriously considering to migrate our production database from PostgreSQL to ZODB. I am about to implement our product database, and it

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-11 Thread Joachim Werner
The other motivations for an RDBMS are (1) people have existing schemas and want Zope to access the same data as their existing apps, and they want it to be transparent, and (2) tables with millions of entries are easily stored in Zope but the perception is that the catalog isn't as fast as

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-11 Thread Casey Duncan
Cees de Groot wrote: Shane Hathaway [EMAIL PROTECTED] said: That's one reason ZODB is so nice. You can write an application without writing a formal schema. One of the reasons I am seriously considering to migrate our production database from PostgreSQL to ZODB. I am about to implement

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-11 Thread David Brown
At 11:45 AM 5/11/2001 -0600, Casey Duncan wrote: One of the biggest limitations in my mind is the lack of a general query language for the ZODB like what you get with most OODBMS and all RDBMS. I used to think this as well. But isn't Python a decent query language? Isn't it nice to be able to

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-11 Thread Joachim Werner
But isn't Python a decent query language? Isn't it nice to be able to have all of the facilities of Python at your disposal when manipulating data, rather than hoping that whatever database you are using doesn't have a brain-damaged implementation of SQL? Most of the time nobody will need

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-11 Thread David Brown
At 08:38 PM 5/11/2001 +0200, you wrote: E.g. how would you handle objects beloning to more than one container? In SQL this is easy (Just have a table that matches key pairs from the container table and the item table). I could do the same thing with Python, creating a dictionary that does

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-11 Thread Cees de Groot
Joachim Werner [EMAIL PROTECTED] said: [...]. E.g. how would you handle objects beloning to more than one container? In SQL this is easy (Just have a table that matches key pairs from the container table and the item table). And I don't know any good way of implementing many-to-many relations in

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-10 Thread Shane Hathaway
Tino Wildenhain wrote: I think the motivation people want an RDBMS storage beneth zodb is because they understand RDBMSes these days are performant, relieable and can quiete easy maintained. The other motivations for an RDBMS are (1) people have existing schemas and want Zope to access the

Re: oodb philosophics ;) was: Re: [Zope-dev] Experiments with ORMapping

2001-05-10 Thread Casey Duncan
Tino Wildenhain wrote: Hi shane, I think the motivation people want an RDBMS storage beneth zodb is because they understand RDBMSes these days are performant, relieable and can quiete easy maintained. I've seen Java implementations using this approach to achive persistens using as