[Zope] sqltest vx. var

[Jeffrey P Shell]

>From: Philip Aylesworth <zopelist@regalint.com>
> I'll correct myself here. I was thinking of the <!--#sqlgroup ...--> tag. I
> don't know what <!--#sqltest ...--> does that <!--#sqlvar name--> or
> <!--#var name fmt=sql--> won't do...

A _very very_ nice feature of #sqltest is the 'multiple' feature.  For
example:

SELECT * FROM inbox
WHERE <!--#sqltest doc_status type=string multiple-->

If doc_status is passed in as a single value, like "foo", the SQL statement
will be rendered as::

SELECT * FROM inbox
WHERE doc_status='foo'

BUT!!! (this is where it gets good), if doc_status is passed in as a
list/sequence, like ["foo", "bar", "drop", "ship"], it will be rendered
as::

SELECT * FROM inbox
WHERE doc_status in ('foo','bar,'drop','ship')

This is an _extremely_ handy feature of #sqltest.  Prior to #sqltest, doing
the above might be like:

SELECT * FROM inbox
WHERE doc_status in (
 <!--#in doc_status-->
 '<!--#var sequence-item fmt=sql-->'
 <!--#else sequence-end-->,<!--#/else-->
 <!--#/in-->)

(#else used to be used where #unless is used today).  The above code also
always required doc_status to be passed in as a sequence.  #sqltest is
smart enough (I believe - i've never been bitten by this) to detect the
difference between strings and lists.

I've used #sqltest with multiple many times with Acquisition where a folder
property would define part of a SQL statement.  That property in some cases
would be a single value, in other places it would be a tokens or lines
property.

So, in otherwords, you get the type checking, the multiple, the optional,
etc... with #sqltest that you don't get otherwise.  About the only problem
is that #sqltest currently doesn't do not-equals or "not in (...)".

.jPS | jeffrey@digicool.com
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