I have some data that will not naturally live as an item in a folder. If I'm using Zope, how do I establish a root for it? The ZODB docs talk about how to handle a free-standing database, but I don't see info about how to use the one that Zope has already set up. I recall there's some way to get a handle to the open database, but I don't recall exactly what. Can anybody help me out? If I use a class variable, will that be persisted automatically, e.g. class MyManager(Persistence.Persistent): MyClassVariable = SomePersistentClass() ..... ? (Actually, I'm not sure if it matters whether MyManager is a subclass of Persistent). Or, if it is not automatically persistent, is there anything I can do to make it persistent so that it will obey the transaction boundaries coming from web requests? Final question, which is distinct from the root objects issue: if I use Zope's Persistent List, will that avoid the problem of faulting in the whole list if I don't need it? I am looking for a good way to keep a record of transactions. ZODB's raw transaction recording is probably not quite right since it has the wrong granularity, it mixes a lot of unrelated transactions (it's only some I want), and I think it can get zapped if I do various database compactions and cleanups. Thanks.
At 09:37 PM 1/23/02 -0800, Ross Boylan wrote:
I have some data that will not naturally live as an item in a folder. If I'm using Zope, how do I establish a root for it? The ZODB docs talk about how to handle a free-standing database, but I don't see info about how to use the one that Zope has already set up. I recall there's some way to get a handle to the open database, but I don't recall exactly what. Can anybody help me out?
If I use a class variable, will that be persisted automatically, e.g. class MyManager(Persistence.Persistent): MyClassVariable = SomePersistentClass() ..... ? (Actually, I'm not sure if it matters whether MyManager is a subclass of Persistent).
Or, if it is not automatically persistent, is there anything I can do to make it persistent so that it will obey the transaction boundaries coming from web requests?
I just realized that I can hang the persistent object off the item or folder that is my product. I'm still curious what the other options are.
Final question, which is distinct from the root objects issue: if I use Zope's Persistent List, will that avoid the problem of faulting in the whole list if I don't need it? I am looking for a good way to keep a record of transactions. ZODB's raw transaction recording is probably not quite right since it has the wrong granularity, it mixes a lot of unrelated transactions (it's only some I want), and I think it can get zapped if I do various database compactions and cleanups.
Thanks.
At 09:37 PM 1/23/02 -0800, Ross Boylan wrote:
I have some data that will not naturally live as an item in a folder. If I'm using Zope, how do I establish a root for it? The ZODB docs talk about how to handle a free-standing database, but I don't see info about how to use the one that Zope has already set up. I recall there's some way to get a handle to the open database, but I don't recall exactly what. Can anybody help me out?
Continuing to talk to myself.... I finally found some old notes. For the record (unless things have changed) conn = aPersistentObject._p_jar will retrieve the connection. One can then get the root with conn.root() Thanks to Jim Fulton who originally explained this to me. I'm still wondering about class variables being persistent and the efficiency of PersistentList, if anyone has any comments.
If I use a class variable, will that be persisted automatically, e.g. class MyManager(Persistence.Persistent): MyClassVariable = SomePersistentClass() ..... ? (Actually, I'm not sure if it matters whether MyManager is a subclass of Persistent).
Or, if it is not automatically persistent, is there anything I can do to make it persistent so that it will obey the transaction boundaries coming from web requests?
Final question, which is distinct from the root objects issue: if I use Zope's Persistent List, will that avoid the problem of faulting in the whole list if I don't need it? I am looking for a good way to keep a record of transactions. ZODB's raw transaction recording is probably not quite right since it has the wrong granularity, it mixes a lot of unrelated transactions (it's only some I want), and I think it can get zapped if I do various database compactions and cleanups.
Thanks.
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On Wed, 23 Jan 2002, Ross Boylan wrote:
I'm still wondering about class variables being persistent and the efficiency of PersistentList, if anyone has any comments.
Class variables are *not* persisted, since they are class data and not instance data. I believe that a PersistentList is a monolithic object (a Python dictionary that just has "trigger the persistence machinery" hooks wrapped around the data access methods), so accessing it will bring the whole list into memory. If you want to avoid that, and only pull in (mostly) the data that you need, take a look at the BTree object type. --RDM
participants (2)
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R. David Murray -
Ross Boylan