[Zope-dev] Z SQL Method problems (now two confirmed bugs)

[Andy Dustman]

[Moving this to Zope-Dev] I've done some more investigation and determined
there is a fundamental flaw in the way Z SQL Method parameters are
handled.

On Tue, 7 Aug 2001, Andy Dustman wrote:

> I have a Z SQL Method (SELECT) with the following parameters:
>
> HostId DomainId Name IP
>
> and the following SQL:
>
> SELECT
> HostId, DomainId, RecordType, Name, IP, Distance, Target, TTL,
> StartEndTime, Location, Updated
> FROM Hosts
> <dtml-sqlgroup where>
> <dtml-sqltest HostId column="HostId" type=int optional>
> <dtml-and>
> <dtml-sqltest DomainId column="DomainId" type=int optional>
> <dtml-and>
> <dtml-sqltest Name column="Name" type=nb optional>
> <dtml-and>
> <dtml-sqltest IP column="IP" type=int optional>
> </dtml-sqlgroup>
>
> Note that all tested columns are optional. Using the Test tab, everything
> works correctly: If I leave off values, that portion isn't rendered.
>
> Now... I have a DTML Method which performs:
>
> <dtml-in SELECT mapping> ... </dtml-in>
>
> This bombs unless all the parameters are specified in form data.

Now, for the reason it bombs: When called, a Z SQL Method ultimately gets
information about parameters from the parse() function in Aquaduct.py. For
each parameter parsed (and there are problems with the parsing, but that's
another problem), it checks trys three things:

1) Get the parameter value from REQUEST.

2) Failing that: Assign the parameter it's default value, if it exists.

5^H3) Failing that: If the parameter is marked optional, ignore it.

Here is the problem: There is no way for parse() to mark a parameter as
optional. It simply is not tested for in any way. It also cannot get this
information from the <dtml-sqltest ...> element, because it doesn't have
access to it or the template.

Solution: parse() does have the capability of finding a parameter type
(for the above-mentioned reason), i.e. the parameters could be written:

HostId:int DomainId:int Name:nb IP:int

I propose also allowing :optional to follow the type, so that parse() can
set this properly, i.e.:

HostId:int:optional DomainId:int:optional Name:nb:optional IP:int:optional

Note that currently default values take precedence over optional values
(if it could find any).

I'll prepare a patch that can do this if requested (DC/ZopeCorp decide
this is a good solution) and it will also fix the parameter="value"
parsing problem (broken in 2.4.0).

-- 
Andy Dustman         PGP: 0xC72F3F1D
    @       .net     http://dustman.net/andy
I'll give spammers one bite of the apple, but they'll
have to guess which bite has the razor blade in it.