sql joins and the revDataFromQuery function

Jan Schenkel janschenkel at yahoo.com
Thu Jun 12 00:25:01 EDT 2003


--- rand valentine <jrvalent at wisc.edu> wrote:
>  I am working on a database using Valentina and
> RunRev. I am just learning
> sql and have discovered that sql joins will be key
> to a lot of my
> development. So I constructed a join, which looks
> like the following:
> 
> SELECT BasicLexicon.Nishnaabemwin, BasicLexicon.PoS,
> Keys.Key, Keys.PoS,
> Keys.SubKey, Keys.UniqueCode FROM BasicLexicon, Keys
> WHERE
> BasicLexicon.UniqueCode = Keys.UniqueCode
> 
>  The details aren't important -- Basically, all this
> is doing is getting
> information from _two_ different tables in a
> Valentina database, and
> stitching them together. Here's my question -- Why
> does this work with the
> following function call:
> 
>   put revDataFromQuery(,,1,myJoin,) into fld
> "dataset"
> 
> This does exactly what I want! What puzzles me is
> the fact that the
> revDataFromQuery seems to require a single database
> ID:
> 
>
revDataFromQuery([columnDelim],[rowDelim],databaseID,SQLQuery[,varsList])
> 
> So how can this join succeed, since it's looking up
> two distinct queries as
> defined by the Database Query Builder, and I only
> passed it the index of one
> (1)? Is this a bug soon to be corrected, or am I
> missing something? Thanks.
> 
> rand valentine 
> 

Hi Rand,

The reason why Valentina can figure it out, is that
one database can contain multiple tables. In fact, if
the tables were in separate databases, Valentina
couldn't possibly link these two tables. (*)

Hope this helped,

Jan Schenkel.

(*) except of course if you were to import one of the
tables into the other database as a temporary table,
but I digress.

=====
"As we grow older, we grow both wiser and more foolish at the same time."  (La Rochefoucauld)

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