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Re: InstantDB: select madness


Sascha

OK - got it. You either need to add a line of SQL before the query:

SET LITERALS STRICT_ON

Or you need to add modify the line in sample.prp from:

    strictLiterals=0

to

    strictLiterals=1

By default, InstantDB interprets "mycol" as a column name if it can find a
column name that matches. Setting the above property forces everything in
quotes to always be treated as a string literal. I had this switched on in
the database I tried your script with, which is why I didn't get it to work.
If you want to know why it does this, visit:

http://instantdb.enhydra.org/software/documentation/types.html#StringLiteral
s

So...

SELECT DISTINCT unitId FROM UnitOptions
WHERE fieldname="targetArea" AND value="Berlin";

There's no column called targetArea in the above query, so it behaves as
expected.

SELECT * FROM Unit
WHERE Unit.id IN
    (SELECT DISTINCT unitId FROM UnitOptions WHERE value="Berlin");

Again no ambiguity.

SELECT * FROM Unit
WHERE Unit.id IN
    (SELECT DISTINCT unitId FROM UnitOptions
    WHERE fieldname IN ("targetArea") AND value="Berlin");

Here, columns ar not allowed in the IN clause, so no attempt is made to see
if targetArea could be a column.

SELECT * FROM Unit
WHERE Unit.id IN
    (SELECT DISTINCT unitId FROM UnitOptions
    WHERE fieldname="targetArea" AND value="Berlin");

Here, targetArea gets picked up from the outer select, so InstantDB will try
to perform a correlated sub-select. This returns no value because there are
no rows where Unit.targetArea=UnitOptions.fieldname.

Regards

Pete

--

Peter Hearty                         peter.hearty@lutris.com
Lutris Technologies (UK)        http://www.lutris.com
----- Original Message -----
From: "Sascha Matzke" <sascha@bespin.de>
To: <instantDB@enhydra.org>
Sent: Tuesday, October 03, 2000 3:36 PM
Subject: Re: InstantDB: select madness


> Hello,
>
> On Tue, Oct 03, 2000 at 03:19:27PM +0100, Peter Hearty wrote:
> > What version of InstantDB are you using?
>
> 3.21 but the database was created with 3.20beta2
>
> > > SELECT * FROM Unit WHERE Unit.id IN (SELECT DISTINCT unitId FROM
> > > UnitOptions WHERE fieldname="targetArea" AND value="Berlin")
> > >
> > > So... The above doesn't work...
>
> > Do you get an exception, or does it return the wrong data? If the
> > wrong data then too much or too little or just the wrong value?
>
> I get no exception... no data either..
>
> > A script that creates the two tables, adds some data to illustrate
> > the problem would really help.
>
> I attached a sample script...
>
> Sascha
> --
> .-> Sascha Matzke - sascha@bespin.de ------------------------.
> |   Eure Moral, Eure MGs werden nicht ewig regier'n...       |
> |                                         Anarchist Academy  |
> `-- On this earth for  24 years,  355 days  <----------------'
>
>

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