Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!bloom-beacon!bu-cs!berlin
From: berlin@bu-cs.BU.EDU (David K. Fickes)
Newsgroups: comp.databases
Subject: Re: INGRES/EQC and SQL/C ...and general notes...
Summary: yes but...
Message-ID: <24585@bu-cs.BU.EDU>
Date: 26 Aug 88 21:11:07 GMT
References: <24546@bu-cs.BU.EDU> <2401@rtech.rtech.com>
Reply-To: berlin@buita.bu.edu (David Fickes Einstein Project)
Followup-To: comp.databases
Organization: Boston University - Einstein Papers Project
Lines: 49

Yes a simpler QUEL statement will do it .. BUT ONLY IF ALL OF THE RESULTS
ARE A CORRECT DATE... take the string "00/00-02/89?" and put it through our two
statements as one of 40,000 records ...  
(if INGRES would allow the nesting...) 
and the one transaction would fail... not a problem unless you have 39,999
other records that would be changed.

If I use my statement 39,999 would change and I could 
easily find the one other...

In yours... the transaction fails on an UNKNOWN record and NO 
RECORDS ARE CHANGED leaving me to write more code to TRAP the one failure...

The only other real way is to work with the TID... or the UNIQUE
ID NUMBERS (d.uid) which I maintain with our records...  Now back 
to the original question

WHY CAN'T WE NEST THE DARN QUEL STATEMENTS?


In article <24546@bu-cs.BU.EDU>, berlin@bu-cs.BU.EDU (David K. Fickes) writes:
> 
> One other question. What's so hard about supporting NESTED EQUEL
> statements in the EQUEL/C processor???  I've got some code that looks like 
> this:
> 
> ## ingres "einstein"
> ## range of d is dukasfin3
> ## retrieve (c_uid=d.uid) where d.date=" " and
> ##      squeeze(d.doc_date)="00/00/??";
> ##{
> ##      retrieve (c_year=right(squeeze(d.doc_date),2)) where d.uid=c_uid;
> ##      replace d(date=date(01/01/c_year)) where d.uid=c_uid;
> ##}
> 

Actually, a this can be done using a single QUEL REPLACE statement.

##	replace d (date = date("01/01/"+right(squeeze(d.doc_date),2)))
##		where d.date=" " and squeeze(d.doc_date)="00/00/??";
	

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David K. Fickes     Center for Einstein Studies/Einstein Papers Project
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