[GNUe-dev] Re: [GNUe] cascade insert into master detail

[Jan Ischebeck]

Hi Reinhard,

Just my 2cents concerning the *never* changing nature of OIDs / rowids.

Oracle databases provides the attribute "rowid" for each database
record. Till version 9i it was correct that the
rowid would never change, because it describes the physical location of
the row.
Since version 10g there is the table option ROW MOVEMENT which allows
rows to be moved, and their physical location to be changed.
So ROWIDs *can* change.

Postgresql recommends not to use OIDS: "The oid type is currently
implemented as an unsigned four-byte integer. Therefore, it is not large
enough to provide database-wide uniqueness in large databases, or even
in large individual tables."
(http://www.postgresql.org/docs/8.1/static/datatype-oid.html)

Regards,
Jan

Reinhard Mueller schrieb:
> primarykey: will be used to find a record again after it has been
> changed. Gnue-forms relies on the assumption that the primary key of a
> record never changes through triggers or stored procedures. This concept
> fails for newly inserted records if the primary key is set from a
> sequence (see above). If a rowid is available, it is preferred over the
> primary key, since the rowid is guaranteed to *never* change
>