Code

Ticket #4102: 4102-modified.patch

File 4102-modified.patch, 5.0 KB (added by SmileyChris, 7 years ago)

Latest version of the patch, reimplemented checking against the existing value after a discussion with Collin because otherwise user input like forms/etc is going to mark everything modified regardless

  • django/db/models/base.py

     
    102102    def __ne__(self, other): 
    103103        return not self.__eq__(other) 
    104104 
     105    def __setattr__(self, name, value): 
     106        if name not in self._modified_attrs: 
     107            if not hasattr(self, name) or value != self.__dict__[name]: 
     108                self._modified_attrs.append(name) 
     109        self.__dict__[name] = value 
     110 
     111    def _reset_modified_attrs(self): 
     112        self.__dict__['_modified_attrs'] = [] 
     113 
    105114    def __init__(self, *args, **kwargs): 
     115        self._reset_modified_attrs() 
    106116        dispatcher.send(signal=signals.pre_init, sender=self.__class__, args=args, kwargs=kwargs) 
    107117 
    108118        # There is a rather weird disparity here; if kwargs, it's set, then args 
    109         # overrides it. It should be one or the other; don't duplicate the work 
     119        # overrides it. It should be one or the other; don't duplicate the work. 
    110120        # The reason for the kwargs check is that standard iterator passes in by 
    111         # args, and nstantiation for iteration is 33% faster. 
     121        # args, and instantiation for iteration is 33% faster. 
    112122        args_len = len(args) 
    113123        if args_len > len(self._meta.fields): 
    114124            # Daft, but matches old exception sans the err msg. 
     
    207217    _prepare = classmethod(_prepare) 
    208218 
    209219    def save(self, raw=False): 
     220        "Save model object to database, creating if doesn't exist, otherwise updating" 
    210221        dispatcher.send(signal=signals.pre_save, sender=self.__class__, instance=self) 
    211222 
    212223        non_pks = [f for f in self._meta.fields if not f.primary_key] 
     224        modified_attrs = self._modified_attrs 
     225        non_pks = [f for f in non_pks if (f.name in modified_attrs or 
     226                                          f.attname in modified_attrs)] 
     227        self._reset_modified_attrs() 
    213228        cursor = connection.cursor() 
    214229 
    215230        qn = connection.ops.quote_name 
  • django/db/models/query.py

     
    204204                                                    index_start=0, max_depth=self._max_related_depth) 
    205205                else: 
    206206                    obj = self.model(*row[:index_end]) 
     207                    # Models keep a track of modified attrs to choose which 
     208                    # fields to save. Since we're just pulling from the 
     209                    # database, nothing has changed yet. 
     210                    obj._reset_modified_attrs() 
    207211                for i, k in enumerate(extra_select): 
    208212                    setattr(obj, k[0], row[index_end+i]) 
    209213                yield obj 
  • tests/modeltests/update_fields/models.py

     
     1""" 
     2#. Save only modified fields on update 
     3""" 
     4from django.db import models 
     5 
     6class Article(models.Model): 
     7    headline = models.CharField(maxlength=100, default='Default headline') 
     8    body = models.TextField() 
     9    pub_date = models.DateTimeField() 
     10 
     11    class Meta: 
     12        ordering = ('pub_date','headline') 
     13 
     14    def __str__(self): 
     15        return self.headline 
     16 
     17__test__ = {'API_TESTS':""" 
     18# Create a couple of Articles. 
     19>>> from datetime import datetime 
     20>>> a = Article(headline='Article 1', body='Body 1', pub_date=datetime(2007, 5, 5)) 
     21>>> a.save() 
     22 
     23# Change headline and body on different instances, then save both to verify 
     24# that each only updated the modified field. 
     25>>> a1 = Article.objects.get(pk=a.id) 
     26>>> a2 = Article.objects.get(pk=a.id) 
     27>>> a1.headline = 'Changed article 1' 
     28>>> a2.body = 'Changed body 1' 
     29>>> a1.save() 
     30>>> a2.save() 
     31>>> a3 = Article.objects.get(pk=a.id) 
     32>>> a3.headline 
     33u'Changed article 1' 
     34>>> a3.body 
     35u'Changed body 1' 
     36 
     37# Fields entered at instantiation of a model which will already exists should be 
     38# saved as well. 
     39>>> a = Article(id=a.id, headline='Reset article 1', body='Reset body 1', pub_date=datetime(2007, 5, 5)) 
     40>>> a.save() 
     41>>> a3 = Article.objects.get(pk=a.id) 
     42>>> a3.headline 
     43u'Reset article 1' 
     44>>> a3.body 
     45u'Reset body 1' 
     46 
     47# If the value doesn't change, it won't be marked as modified -- otherwise user 
     48# input like forms/etc is going to mark everything modified regardless. 
     49>>> a1 = Article.objects.get(pk=a.id) 
     50>>> a2 = Article.objects.get(pk=a.id) 
     51>>> a1.headline = 'Changed article 2' 
     52>>> a2.headline = a2.headline 
     53>>> a2.body = 'Changed body 2' 
     54>>> a1.save() 
     55>>> a2.save() 
     56>>> a3 = Article.objects.get(pk=a.id) 
     57>>> a3.headline 
     58u'Changed article 2' 
     59>>> a3.body 
     60u'Changed body 2' 
     61"""}