On 12/24/2014 11:04 AM, Dimitry Sibiryakov wrote: > 24.12.2014 16:59, Mark Rotteveel wrote: >> On 24-12-2014 16:56, Dimitry Sibiryakov wrote: >>> 24.12.2014 16:39, Jim Starkey wrote: >>>> Sorry, that's backwards. Changes to the minor version are upwards >>>> compatible -- a new engine can work against an older database. If a >>>> change is backwards compatible, there is no reason to change the ODS >>>> version at all. >>> How SELECT NEW_FIELD FROM SYSTEM_TABLE is supposed to work against >>> older databases? >> That is the reverse of what you were initially asking. > No, I asked exactly that. Older engines don't need new fields, they can > work with new > ODS easily. Newer engines need new fields, they cannot work with old ODS. > That's how I > understand it.
No, an older engine can't know what has changed, so there is no way it can access a more recent minor ODS. By definition, an engine must be able to understand all earlier minor versions of the same major version. It new system fields aren't there, the engine must be able to work around that. If it can't handle all earlier minor versions, the major version has to be bumped. In subsequent systems, I have decoupled system tables from the ODS version (I'd be happy to explain if anyone cares). NuoDB takes this one step further by eliminating the concept of an ODS completely. > ------------------------------------------------------------------------------ Dive into the World of Parallel Programming! The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
