Le 14/12/11 22:05, Mark Stanton a écrit :
Hi Mark, > If I'm not mistaken (although I might be and I haven't got the time > to go back and check) and odb file is effectively a zip file with > various things in it. Yes. > I believe HSQL is a "cut down" database, on the basis that a lot of > the bells and whistles of a full database engine aren't required by > small applications. Hence it's a small, fast database, without it's > own data storage, I imagine, since the data for it *is* kept in the > odb file. Hmm, I wouldn't say "cut down", it is actually rather good, certainly in its latest incarnation, which is not included as the engine for OOo/LO ODB files. It can be used with its own independent storage too, but then you have to set it up in server/client mode, i.e. LO becomes the client (via and ODB file) and hsqldb.jar runs as a "server". In the current setup of LO/hsqldb, the data is effectively stored within the ODB file. In fact, the whole of the hsqldb.jar is loaded into memory when the ODB file is opened. This is then used (via a Java2uno bridge, at least that is how I understand it) to access tables, queries, forms, etc, so everything resides in memory, which is fine...until your app crashes, you run out of memory, or you have a power cut, and then...you cry your heart out, throw a wobbly, or swear til the air turns blue, when you discover your precious ODB file has either been corrupted or the data you have been entering for the last 3 hours has not been saved. And all of this is absolutely not hsqldb's fault, but OOo/LO's because of the way it was decided at the time to integrate hsqldb into OOo. There are moves afoot to switch to SQLite as the default db backend engine. Whether that will actually work, whether it will result in one or several files, remains to be seen. Personally, I hope that the multifile option will be chosen, and that we will just use the LO ODB container as a front end, so that the db data will always be accessible outside of the LO app and readable by any SQLite compliant reader. Here's hoping... Alex -- For unsubscribe instructions e-mail to: [email protected] Problems? http://www.libreoffice.org/get-help/mailing-lists/how-to-unsubscribe/ Posting guidelines + more: http://wiki.documentfoundation.org/Netiquette List archive: http://listarchives.libreoffice.org/global/users/ All messages sent to this list will be publicly archived and cannot be deleted
