--- In firebird-support@yahoogroups.com, "Ann W. Harrison" <aharrison@...> wrote:
>
> flyingfb wrote:
> >
> > sometimes, we need change the metadata, for example, change
> > type of a column from Integer to varchar, we thought we must
> > backup and restore, is it right?
>
> You can make many data type changes by altering a field to a
> larger type in the same "group" - e.g. smallint to int or
> double and strings to larger strings.
>
> Changing between "groups" - integers to strings, for example -
> requires something more elaborate. Backup/restore won't do it,
> because the backup includes the data definitions.
>
>
> The usual procedure is to add a new temporary field of the
> type you want to the table, copy the data to the new field,
> drop the old field and rename the new field to the old name.

i have believe it for a long time that backup and restore can do that.

> That gets complicated when the table is referenced in views,
> procedures, etc. If you're facing a major set of schema
> changes, look at the tools available here
>
> http://www.ibphoenix.com/main.nfs?a=ibphoenix&page=ibp_contrib_download
>
>
> Good luck,
>
> Ann
>