Re: INFORMIX disk mirroring across a LAN ?

Path: emory!samsung!zaphod.mps.ohio-state.edu!pacific.mps.ohio-state.edu!linac!unixhub!slacvm!ian From: IAN@SLACVM.SLAC.STANFORD.EDU Newsgroups: comp.databases Message-ID: <91207.074617IAN@SLACVM.SLAC.STANFORD.EDU> Date: 26 Jul 91 15:46:17 GMT References: <863@ghp.UUCP> Organization: Stanford Linear Accelerator Center Al Parker asked about disk mirroring of an Informix database across a Lan. I am unfamiliar with Informix and am thus igmorant of exactly what the Informix disk mirroring utility does. I do know disk mirroring is in general. However it is possible to update two databases simultaneously and keep them in sych. I have achieved this in Oracle, but it may be possible in any relational database which supports embedded sql. The technique takes advantage of a 3GL's capability to explicitly connect to more than one database. The method uses SQL*FORMS (Oracle's screen input/output utility) and user exits. When the form is initialized a user exit establishes the explicit connection to the other database, and returns to the form without breaking the connection. There are three user exits which handle insert, update and delete operations. All of them work by passing data from the form to the user exit host variables, the user exit then uses the values in the host variables to write the record at the other database. If that write is successful control is returned to the form which commits the record as usual. The last user exit breaks the explicit connection to the second database. Ian MacGregor [Stanford Linear Accelerator Center] The above does not represent an endorsement of Oracle by the Department of Energy, Stanford University, nor the Stanford Linear Accellerator Center.