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From: dmc@sei.cmu.edu (Dawn Cappelli)
Newsgroups: comp.databases
Subject: Re: Update in INGRES via view
Message-ID: <3352@fp.sei.cmu.edu>
Date: 12 May 89 14:17:44 GMT
References: <7501@spool.cs.wisc.edu>
Reply-To: dmc@sei.cmu.edu (Dawn Cappelli)
Organization: Software Eng. Inst.;Carnegie-Mellon U.; Pittsburgh, PA 15213   _USA_
Lines: 30

In article <7501@spool.cs.wisc.edu> beverly@ai.cs.wisc.edu (Beverly Seavey) writes:
>
> Is it possible to do updates in INGRES via views? 

You can update through views in INGRES, except for the following 
situations:

	- You can't update the columns in the search condition of 
		the view definition
	- You can't update columns that are set functions or computations
	- You can't update on views that have more than one base table.

This information is in the INGRES Application Developer's Training manual.

However, views are theoretically for VIEWING data, and really shouldn't
be used for updating.  You can use the view for retrieving the data and
displaying it on the form, but why not just update the base tables 
directly then using the acid number (which can be placed in a hidden 
field when the data is retrieved)?

I believe that updating through views is not legal in ANSI standard SQL, 
so you're better off avoiding that capability, even though it does exist.



-- 
Dawn Cappelli				dmc@sei.cmu.edu
Software Engineering Institute		(412) 268-6170
Carnegie Mellon University
Pittsburgh, PA