Re: Informix vs. Sybase vs. SQL Server vs. Oracle

Andreas Zeugswetter wrote: > Oracle's only advantage is with concurrent read and update, > since it does not need a read lock. > But if you use dirty read isolation, you don't have read locks in > Informix either. Oralce read a row without read lock and get current value without write lock on the row and before image or old value with write lock on the row. Old value is not, and better than dirty read because the isolation level is higher. Right? Futhermore, two transaction can update same table without specifying rowno in Oracle. But can not in Informix. We can test and discuss more. LiuJun