Subject Re: [firebird-support] Firebird database portability
Author Helen Borrie
First, please show consideration to others by removing tags inserted
into the Subject header by your anti-spam tools.

At 04:18 PM 28/11/2006, you wrote:

> > Is the firebird database machine independent?
> >
> > Or are the following files machine independent?

Next thing is to get your head around what you mean by "machine
independent". Are you talking hardware architecture, filesystem
structure or operating system. By your comments you seem confused
about what you mean.

> > firebird.msg

Will get installed by the platform + architecture specific
installer. It is not a user file and shouldn't be treated as portable.

> > > security.fdb

This is a system file too, but it is a database. Databases are
portable between operating systems (and filesystems, too, more or
less...) provided the machine architecture is the same. So you *can*
filecopy a database from Windows on Intel-86 to Linux on Intel-86 -
but it's not recommended as ideal.

>Windows <-> Windows don't quite count as machine independent. By machine
>independent I mean it does not matter what architecture or OS the box is
>using, the installed programs will be able to use the files.

Architecture and OS are two entirely distinct things. Don't confuse them.

>Windows <->
>Windows on the same architecture is not quite what I had in mind.

It would be handy if you did express what you had in mind, rather
than launch a lead canoe based on the premise that all hollow objects
can float.

>Something like cdb is machine independent. I
>can copy a cdb database from a Solaris box to a FreeBSD box and it would
>work with the local cdb programs and regardless of cpu architecture too.

Well, you could if the Solaris operating system was running on the
same machine architecture as the FreeBSD operating system. But you
couldn't copy between e.g. Solaris Intel and Solaris Sparc....or
between say FreeBSD running on Intel and MacOSX running on Motorola.

>If I remember correctly, you could copy a mysql database from a windows
>box to a linux box and vice versa.

Intel to Intel, probably....I say that because I've yet to hear of
anyone actually getting it to work on all points. But theoretically
it should be possible. With Firebird it is...though *copying*
databases at all is not a sensible thing to risk your job for.

>You can copy a mysql database from a 32-bit Linux system to a 64-bit
>Linux system.
>This means that the mysql database too is machine independent.

If it is true (which I don't think it is, actually) it doesn't mean
that the mysql database is machine independent. Again, I think it
would be very unwise to stake your job on that assumption. At best
(if it works) it means that the 64-bit operating system (whatever it
might be) can recognise data that was stored by a 32-bit engine and
do the right things with numerics, et al. I don't think date/time
types are an issue with MySQL since, afair, MySQL stores dates as strings.

Firebird gets past the issues with all of the aspects of portability,
be it machine architecture, operating system or filesystem, by
providing the ability to convert a database to a transportable backup
file, which is not a database at all but a metadata schema script and
data stored in XDR portable data format. The tool that works this
miracle is gbak. gbak -b -t creates the transportable file; gbak -c
recreates the database according to the operating system, filesystem
and machine architecture that the Firebird server at its new home is
operating on.