5 May
2008
5 May
'08
5:55 p.m.
Hi All,
This question "might" be related to the thread that has been active in the
past couple of days about the data model.
We have a similar situation with the only difference being that we want to
create lists or collections (like Groups) of certain pre- created Objects.
The Object as a whole may/will belong to more than one such collection -
which means that if we were to use a Document to link a Collection and its
contents, then every document will have a COPY of the same object and this
is definitely not desirable for good performance - Right?
So, in that case, we have 2 alternatives:
1) Use the techiniques used in XWiki to create Groups: each group has
objects of class XWikiGroup with just one field that refers to the Member
name. OR
2) Use XWiki.getHashmap() and add the Collection and its members to the
hashmap (as the Key and Value resp.)
The XWiki API indicates that the option #2 must be used in xwiki when
Objects can not be created.
My Question is:
-> Even though I could use option #1 and create objects and add them to the
document that would represent the Collection, can I still use option #2
because I think that it will provide better performance. Am I right in my
assumption? What should I do?
Thanks a lot for all help!
5 May
5 May
8:45 p.m.
Kamna Jain wrote:
Hi All,
This question "might" be related to the thread that has been active in the
past couple of days about the data model.
We have a similar situation with the only difference being that we want to
create lists or collections (like Groups) of certain pre- created Objects.
The Object as a whole may/will belong to more than one such collection -
which means that if we were to use a Document to link a Collection and its
contents, then every document will have a COPY of the same object and this
is definitely not desirable for good performance - Right?
Right. Any duplication (except for backup purposes) is bad.
So, in that case, we have 2 alternatives:
1) Use the techiniques used in XWiki to create Groups: each group has
objects of class XWikiGroup with just one field that refers to the Member
name. OR
Yes, this is somehow similar to the Foreign Key concept in databases, so
it should be a good way to approach your problem.
2) Use XWiki.getHashmap() and add the Collection and
its members to the
hashmap (as the Key and Value resp.)
The XWiki API indicates that the option #2 must be used in xwiki when
Objects can not be created.
My Question is:
-> Even though I could use option #1 and create objects and add them to the
document that would represent the Collection, can I still use option #2
because I think that it will provide better performance. Am I right in my
assumption? What should I do?
#2 is a bit faster, but it does not provide persistence. When the
current request is over, that hashmap is gone. Given the fact that you
probably have to store your data in a database, in the end you get
almost the same performance as #1, but you have to reimplement what the
XWiki platform already offers.
When using a platform (any platform), you have to get used to the best
practices of that platform; this is true for XWiki also: although some
might be used to low level improvements of storage and SQL queries, and
feel that they know better how queries should be written, XWiki offers a
simple, high-level data model that should be used. The Google BigTable
model was also received by some with dismay, since it doesn't follow the
classical SQL principles.
--
Sergiu Dumitriu
http://purl.org/net/sergiu/
7 May
7 May
12:06 a.m.
Sergiu Dumitriu wrote:
This explanation easies things for me at least. Please, could you
provide an example? Some thing like how could we retrieve the email
address for all members of a given group? Thanks!
Regards,
Ricardo
--
Ricardo RodrÃguez
Your EPEC Network ICT Team
So, in that
case, we have 2 alternatives:
1) Use the techiniques used in XWiki to create Groups: each group has
objects of class XWikiGroup with just one field that refers to the Member
name. OR
Yes, this is somehow similar to the Foreign Key concept in databases, so
it should be a good way to approach your problem.
12 May
12 May
1:17 a.m.
Hi!
Sergiu Dumitriu wrote:
Kamna Jain wrote:
I feel myself a bit more comfortable with classical SQL concepts so far! :-)
Please, does XWiki provide Referential Integrity? Cascading delete and
cascading update are my concerns at the current point.
I've tried by renaming a document used to "link" a given group-like
class with a number of "group-members". It seems that after I rename
the document, the content of the "link" record remains unchanged.
Working with groups and group members the situation is a bit different:
if I rename an user, she/he is removed from the group/groups it belongs
to. But, in any case, a rename action doesn't respect groups membership
for a given user.
I am working with XE 1.3.8295. Any insight will be welcome!
Thanks!
Cheers,
Ricardo
--
Ricardo RodrÃguez
Your EPEC Network ICT Team
So, in that case, we have 2 alternatives:
1) Use the techiniques used in XWiki to create Groups: each group has
objects of class XWikiGroup with just one field that refers to the Member
name. OR
Yes, this is somehow similar to the Foreign Key concept in databases, so
it should be a good way to approach your problem.
5 May
5 May
11:17 p.m.
New subject: [xwiki-devs] Hashmap vs. Objects (theoretical question about a data model)
Thanks Sergiu.
Your response was very helpful!
On 5/5/08, Kamna Jain <kammy.scorpi(a)gmail.com> wrote:
Hi All,
This question "might" be related to the thread that has been active in the
past couple of days about the data model.
We have a similar situation with the only difference being that we want
to create lists or collections (like Groups) of certain pre- created
Objects.
The Object as a whole may/will belong to more than one such collection -
which means that if we were to use a Document to link a Collection and its
contents, then every document will have a COPY of the same object and this
is definitely not desirable for good performance - Right?
So, in that case, we have 2 alternatives:
1) Use the techiniques used in XWiki to create Groups: each group has
objects of class XWikiGroup with just one field that refers to the Member
name. OR
2) Use XWiki.getHashmap() and add the Collection and its members to the
hashmap (as the Key and Value resp.)
The XWiki API indicates that the option #2 must be used in xwiki when
Objects can not be created.
My Question is:
-> Even though I could use option #1 and create objects and add them to
the document that would represent the Collection, can I still use option #2
because I think that it will provide better performance. Am I right in my
assumption? What should I do?
Thanks a lot for all help!
6 May
6 May
5:05 p.m.
New subject: [xwiki-devs] Hashmap vs. Objects (theoretical question about a data model)
Ok. So I am using Option #1 and now I need to add objects to the document at
the click of a button.
I am able to successfully add the objects to the document but NOT able to
display them on the page (because the template of teh class is not getting
copied)
Thats becuase, I am nto sure how to set the template for that page.
I tried:
1) $doc.setDefaultTemplate..but this did not work
2) I also tried
$response.sendRedirect($projDoc.getURL("view","template=${etemplate}"))
(where etemplate is the encoded template name)
but this gives the error that the document already exists !
3) The only thing that works is when I manually copy
#includeForm("Classsheet") in the wiki editor of my page.
Q: How can I set the template once, so it is used for all objects of that
class.
Thanks
On 5/5/08, Kamna Jain <kammy.scorpi(a)gmail.com> wrote:
Thanks Sergiu.
Your response was very helpful!
On 5/5/08, Kamna Jain <kammy.scorpi(a)gmail.com> wrote:
Hi All,
This question "might" be related to the thread that has been active in
the past couple of days about the data model.
We have a similar situation with the only difference being that we want
to create lists or collections (like Groups) of certain pre- created
Objects.
The Object as a whole may/will belong to more than one such collection -
which means that if we were to use a Document to link a Collection and its
contents, then every document will have a COPY of the same object and this
is definitely not desirable for good performance - Right?
So, in that case, we have 2 alternatives:
1) Use the techiniques used in XWiki to create Groups: each group has
objects of class XWikiGroup with just one field that refers to the Member
name. OR
2) Use XWiki.getHashmap() and add the Collection and its members to the
hashmap (as the Key and Value resp.)
The XWiki API indicates that the option #2 must be used in xwiki when
Objects can not be created.
My Question is:
-> Even though I could use option #1 and create objects and add them to
the document that would represent the Collection, can I still use option #2
because I think that it will provide better performance. Am I right in my
assumption? What should I do?
Thanks a lot for all help!
6025
days inactive
6031
days old
5 comments
3 participants
participants (3)
-
[Ricardo Rodriguez] Your EPEC Network ICT Team -
Kamna Jain -
Sergiu Dumitriu