Horton

Re: PostgreSQL vs SQL/XML Standards

Pavel Stehule <pavel.stehule@gmail.com>

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From: Pavel Stehule <pavel.stehule@gmail.com>
To: Chapman Flack <chap@anastigmatix.net>
Cc: Alvaro Herrera <alvherre@2ndquadrant.com>, Tom Lane <tgl@sss.pgh.pa.us>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>
Date: 2018-10-29T10:16:38Z
Lists: pgsql-hackers 
po 29. 10. 2018 v 11:05 odesílatel Pavel Stehule <pavel.stehule@gmail.com>
napsal:

>
> (It would not be exactly overloading, because of the special sugared
>>> syntax known to the parser, but it could look like overloading, and be
>>> intuitive to the user.)
>>>
>>> If you have convenient access to Oracle to check compatibility, could you
>>> compare this query?
>>>
>>> SELECT * FROM XMLTABLE('.'
>>> PASSING '<sale hatsize="7" customer="alice" taxable="false"/>'
>>> COLUMNS
>>> a boolean PATH 'string("cat" < "dog")',
>>> b boolean PATH 'string("cat" > "dog")',
>>> c boolean PATH 'string(sale/@taxable = false())');
>>>
>>> (I suspect in Oracle it would also work without the string() wrappings,
>>> but just to make it easy, I think this way it will work in both Oracle
>>> and PG—that is, not error, though results may differ.)
>>>
>>
>>
>>
> I have a access to too old 11.2 Oracle.  There I had to modify query
> because there is not boolean type. I replaced bool by int, but I got a error
> ORA-19224:XPTY-004 .. expected node()*, got xs:string - it doesn't work
> with/without string() wrappings.
>

The problem is in last line - the expression  "sale/@taxable = false()" is
not valid on Oracle. Using string() wrapping is a issue, because it returns
"true", "false", but Oracle int doesn't accept it.

Pavel


> Regards
>
> Pavel Stehule
>
>
>
>
>

Commits

  1. Improve documentation about our XML functionality

  2. Improve documentation about our XML functionality.

  3. Add volatile qualifier missed in commit 2e616dee9.

  4. Fix crash with old libxml2

  5. Fix minor deficiencies in XMLTABLE, xpath(), xmlexists()

  6. Fix the BY {REF,VALUE} clause of XMLEXISTS/XMLTABLE

  7. doc: Update README.links

  8. XPath fixes: