Re: Phantom Inserts

Posted in 1995

Nigel Campbell — 6 Mar 1995 23:31:35 GMT — source: Informix-list mailing list archive (1991-1998)

Bruce Horrocks (bh@granby.demon.co.uk) wrote: : In article <pwongD4C773.F15@netcom.com> pwong@netcom.com "Philip S. Wong" writes: : >I was wondering how different databases/vendors implement protection : >against phantom inserts. In particular, how can they achieve phantom : >protection while maintaining a good degree of concurrency? : > : >Example: : [snipped] : Funny how both the responses form Oracle personnel mentioned Rdb : rather than (original) Oracle. The term "read repeatability" is often : used in this situation and is available in Oracle by setting the : appropriate isolation level. Interbase provides phantom protection by default without requiring readers to block writers or vice versa. Rather than use locking on tables or indexes etc InterBase uses row versioning. Your transaction can only see those rows whose transaction id is known to be committed. -- Nigel Campbell Voice: (613) 738-1338 ext 3016 P.O. Box 9707 Desktop Division FAX: (613) 738-0002 3755 Riverside Dr. Cognos Incorporated MCI: nigel campbell || 3074729 Ottawa, Ontario UUnet: nigelc@cognos.COM CANADA K1G 3Z4