Re: WIP - xmlvalidate implementation from TODO list

st 1. 4. 2026 v 16:39 odesílatel Jim Jones <jim(dot)jones(at)uni-muenster(dot)de>
napsal:

>
>
> On 01.04.26 10:10, Pavel Stehule wrote:
> > maybe it can be implemented just as an extension - we don't need DDL
> > commands CREATE XMLSCHEMA - there can be some function. If I understand
> > correctly, the SQL/XML knows just XMLVALIDATE command - and in the first
> > step - this can be just a function too.
>
> Yeah, the spec does not dictate how the schemas are stored or how
> identifiers are mapped to XSDs. The way I see it, in the current state
> of this patch, we miss the option to add XSDs to an existing XMLSCHEMA
> identifier (something like ALTER XMLSCHEMA .. ADD ...), or even the
> option to pass multiple XSDs in CREATE XMLSCHEMA.
>
> It makes the implementation of CREATE XMLSCHEMA (or similar DDL) a bit
> more challenging, as it must always resolve all root's dependencies to
> ensure that XMLVALIDATE has all the necessary info to validate a given XML.
>
> >
> > Theoretically there can be different access - we can introduce a generic
> > XMLVALIDATE command, that can call some callback. This callback can be
> > implemented in an extension. One extension can XML storage identified by
> > relation identifier, another can implement some shared storage on the
> > disc outside the database etc. So the organization of the patch can be
> > different
> >
> > 1. creating API for extensions for implementing loading the schema from
> > some sources.
> > 2. implementation XMLVALIDATE that uses this API
> > 3. creating an extension in contrib, that implements XML storage
> > identified by relational API.
> >
> > Because we don't have an extensible parser, the XMLVALIDATE command
> > should be in core, but other parts are not.
>
>
> How would XMLVALIDATE without this contrib extension look like?
>

The API can be similar to PLpgSQL plugin API - and rendezvous variable

Pavel

>
> Best, Jim
>