Re: Another question Regarding ROWID being Safe

Srinivasa Rao Vaikuntam (srini_v_at_ix.netcom.com) wrote:
: In <326C2BF5.C33_at_infosystem.ch> Daniel Klien <klien_at_infosystem.ch>
: writes:
: >
: >Doug Oldmeadow wrote:
: >>
: >> We have been using ROWID as the key condition to apply updates to a
 row
: >> that has been selected for update. The Administrator's concept
 manual
: >> states this is the fastest method to access a particular row. In
 other
: >> words we select our columns plus ROWID, let the user do user stuff,
 then
: >> update where ROWID = fetched ROWID.
: >>
: >> The manual also says that ROWIDs will change when the data is
: >> unloaded/reloaded - ie some event happens that causes the physical
: >> location of the data to change. Recently, someone suggested that we
: >> should not be using ROWID in this way as "it is not safe".
: >>
: >> My question is - Can ROWID change within the scope of a transaction
 ?
: >> Also, if I do not select for update, is the ROWID still guaranteed
 to be
: >> unique, provided I maintain my connection to the database?
: >>
: >> Any input appreciated.
: >>
: >> Doug OHi Doug
: >
: >You must SELECT FOR UPDATE if you want this guarantee.
: >
: >Bye Dan
 

: I retrieve 10 records from the table, and delete 5 of them from the
: table, after checking for some values. Will the ROWID's of the other 5
: change after the delete operation?

The ROWID will STAY THE SAME for each record across all these transactions. That is: there is no danger of mysteriously changing ROWIDs.

What you should NOT DO is save the ROWID in a table for use later. This is where you risk an EXP/IMP or other shuffling of the data that would screw you up.

Randy :)

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