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SQL Related Articles: Creating views to retrieve data from tables
2003-04-30 -- Geoff Bomford
 
Newsgroups: softvelocity.products.c55ee Create a view of the file and don't nominate any fields, that way the structure always matches the file definition in both dictionaries. MyView VIEW(MyFile) END OPEN(MyView) MyView{Prop:SQL} = 'SELECT * FROM MyFile WHERE...' CLOSE(MyView) Geoff Bomford www.comformark.com.au Computer services For Marketing "Arnor Baldvinsson" wrote in message news:3eaf063d.28885390@news.softvelocity.com... > Hi Glenn, > > On Tue, 29 Apr 2003 14:33:43 -0500, "Glenn Rathke" > wrote: > > >Don't know if it has changed in other versions of Clarion, but SUrf has > >mentioned not to use Select * but rather Select field_one, field_2, where > >the fields are in the order in the dictionary > > If you need the whole record anyway for processing purposes, there is > no advantage of listing the fields over using * as far as I can tell. > Also consider this: > > MyFile... > Record Record > F1 String(10) > F2 Long > F3 String(20) > F4 String(5) > End > > Now if you do: > > MyFile{Prop:SQL} = 'Select MYF.F1, MYF.F4 from ' & Name(MyFile) > Next(MyFile) > > I don't think the values are going to be correct because this doesn't > match the file structure. I may be wrong on this, I haven't tried it. > I know that if you use 'Select *' on a table and the field order in > the db don't match the field order in the file structure you'll get > some odd errors about data conversions - at least with Sybase > SQLAnywhere > > Using a view and only projecting the fields you need would probably be > a better option, but I'm not quite there yet > > Best regards, > > Arnór Baldvinsson

Possible Speed Increases
2003-09-02 � Karl Greenwood 
Using Select field1, field2 ... fieldn should be faster then Select * as
the server has to query its system tables for a field list. In tests using
clarion and asp with ms sql the speed increase was measurable with
mulitple transactions. Having said that a seperate test on a cold fusion
app with ms sql showed no increase.

And as a side note only use Select * if you really need all fields to be
returned
Today is November 21, 2024, 3:56 am
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