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/ _______________________________________________ devs mailing list [email protected] http://lists.xwiki.org/mailman/listinfo/devs
