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Re: Python declarative

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On 01/24/14 11:21, Frank Millman wrote:
> I store database metadata in the database itself. I have a table that 
> defines each table in the database, and I have a table that defines each 
> column. Column definitions include information such as data type, allow 
> null, allow amend, maximum length, etc. Some columns require that the value 
> is constrained to a subset of allowable values (e.g. 'title' must be one of 
> 'Mr', 'Mrs', etc.). I know that this can be handled by a 'check' constraint, 
> but I have added some additional features which can't be handled by that. So 
> I have a column in my column-definition table called 'choices', which 
> contains a JSON'd list of allowable choices. It is actually more complex 
> than that, but this will suffice for a simple example.


I wonder whether your use cases can be fully handled by Xml Schema
standard. It's quite robust and easy to use. You are already doing
validation at the app level so I don't think it'd be much of a problem
for you to adopt it.

e.g.

>>> from spyne.model import *
>>> class C(ComplexModel):
...     title = Unicode(values=['Mr', 'Mrs', 'Ms'])
...
>>> from lxml import etree
>>> from spyne.util.xml import get_validation_schema
>>> schema = get_validation_schema([C], 'some_ns')
>>> doc1 = etree.fromstring('<C xmlns="some_ns"><title>Mr</title></C>')
>>> print schema.validate(doc1)
True
>>> doc2 = etree.fromstring('<C xmlns="some_ns"><title>xyz</title></C>')
>>> print schema.validate(doc2)
False
>>> print schema.error_log
<string>:1:0:ERROR:SCHEMASV:SCHEMAV_CVC_ENUMERATION_VALID: Element
'{some_ns}title': [facet 'enumeration'] The value 'xyz' is not an
element of the set {'Mr', 'Mrs', 'Ms'}.
<string>:1:0:ERROR:SCHEMASV:SCHEMAV_CVC_DATATYPE_VALID_1_2_1: Element
'{some_ns}title': 'xyz' is not a valid value of the atomic type
'{some_ns}C_titleType'.
>>>


Also, if you need conversion between various serialization formats and
Python object hierarchies, I put together an example for you:
https://gist.github.com/plq/8596519

I hope these help.

Best,
Burak

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Python declarative Sergio Tortosa Benedito <sertorbe@gmail.com> - 2014-01-15 18:02 +0100
  Re: Python declarative Francesco Bochicchio <bieffe62@gmail.com> - 2014-01-17 06:22 -0800
    Re: Python declarative Francesco Bochicchio <bieffe62@gmail.com> - 2014-01-19 23:25 -0800
  Re: Python declarative sertorbe@gmail.com - 2014-01-17 06:47 -0800
    Re: Python declarative Tim Roberts <timr@probo.com> - 2014-01-18 13:13 -0800
  Re: Python declarative sertorbe@gmail.com - 2014-01-19 02:27 -0800
  Re: Python declarative sertorbe@gmail.com - 2014-01-22 12:38 -0800
  Re: Python declarative Asaf Las <roegltd@gmail.com> - 2014-01-22 13:16 -0800
    Re: Python declarative Chris Angelico <rosuav@gmail.com> - 2014-01-23 13:29 +1100
    Re: Python declarative Terry Reedy <tjreedy@udel.edu> - 2014-01-22 23:08 -0500
    Re: Python declarative "Frank Millman" <frank@chagford.com> - 2014-01-24 11:21 +0200
      Re: Python declarative Rustom Mody <rustompmody@gmail.com> - 2014-01-24 01:53 -0800
        Re: Python declarative "Frank Millman" <frank@chagford.com> - 2014-01-24 15:06 +0200
    Re: Python declarative Chris Angelico <rosuav@gmail.com> - 2014-01-24 22:18 +1100
    Re: Python declarative "Frank Millman" <frank@chagford.com> - 2014-01-24 14:49 +0200
    Re: Python declarative Burak Arslan <burak.arslan@arskom.com.tr> - 2014-01-24 15:40 +0200
    Re: Python declarative Chris Angelico <rosuav@gmail.com> - 2014-01-25 00:55 +1100
    Re: Python declarative Matěj Cepl <mcepl@redhat.com> - 2014-01-24 17:28 +0100
    Re: Python declarative Chris Angelico <rosuav@gmail.com> - 2014-01-25 03:33 +1100
      Re: Python declarative sertorbe@gmail.com - 2014-01-24 10:51 -0800
    Re: Python declarative "Frank Millman" <frank@chagford.com> - 2014-01-25 09:18 +0200
      Re: Python declarative Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-01-26 02:33 +0000
        Re: Python declarative Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-01-26 02:45 +0000
          Re: Python declarative Asaf Las <roegltd@gmail.com> - 2014-02-02 18:17 -0800
        Re: Python declarative Chris Angelico <rosuav@gmail.com> - 2014-01-26 14:38 +1100
        Re: Python declarative Chris Angelico <rosuav@gmail.com> - 2014-01-26 15:06 +1100
          Re: Python declarative Rustom Mody <rustompmody@gmail.com> - 2014-01-25 20:47 -0800
            Re: Python declarative Chris Angelico <rosuav@gmail.com> - 2014-01-26 16:23 +1100
              Re: Python declarative Rustom Mody <rustompmody@gmail.com> - 2014-01-26 00:05 -0800
                Re: Python declarative "Frank Millman" <frank@chagford.com> - 2014-01-26 11:12 +0200
                Re: Python declarative Rustom Mody <rustompmody@gmail.com> - 2014-01-26 06:36 -0800
          Re: Python declarative Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-01-26 12:05 +0000
        Re: Python declarative "Frank Millman" <frank@chagford.com> - 2014-01-26 08:03 +0200
          Re: Python declarative Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2014-01-26 12:21 +0000
    Re: Python declarative Chris Angelico <rosuav@gmail.com> - 2014-01-25 18:33 +1100
    Re: Python declarative matej@ceplovi.cz (Matěj Cepl) - 2014-01-25 12:23 +0100
  Re: Python declarative Asaf Las <roegltd@gmail.com> - 2014-01-24 04:04 -0800

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