1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428
|
# coding: utf-8
"""
1. Bare-bones model
This is a basic model with only two non-primary-key fields.
"""
from django.db import models, DEFAULT_DB_ALIAS
class Article(models.Model):
headline = models.CharField(max_length=100, default='Default headline')
pub_date = models.DateTimeField()
class Meta:
ordering = ('pub_date','headline')
def __unicode__(self):
return self.headline
__test__ = {'API_TESTS': """
# No articles are in the system yet.
>>> Article.objects.all()
[]
# Create an Article.
>>> from datetime import datetime
>>> a = Article(id=None, headline='Area man programs in Python', pub_date=datetime(2005, 7, 28))
# Save it into the database. You have to call save() explicitly.
>>> a.save()
# Now it has an ID. Note it's a long integer, as designated by the trailing "L".
>>> a.id
1L
# Models have a pk property that is an alias for the primary key attribute (by
# default, the 'id' attribute).
>>> a.pk
1L
# Access database columns via Python attributes.
>>> a.headline
'Area man programs in Python'
>>> a.pub_date
datetime.datetime(2005, 7, 28, 0, 0)
# Change values by changing the attributes, then calling save().
>>> a.headline = 'Area woman programs in Python'
>>> a.save()
# Article.objects.all() returns all the articles in the database.
>>> Article.objects.all()
[<Article: Area woman programs in Python>]
# Django provides a rich database lookup API.
>>> Article.objects.get(id__exact=1)
<Article: Area woman programs in Python>
>>> Article.objects.get(headline__startswith='Area woman')
<Article: Area woman programs in Python>
>>> Article.objects.get(pub_date__year=2005)
<Article: Area woman programs in Python>
>>> Article.objects.get(pub_date__year=2005, pub_date__month=7)
<Article: Area woman programs in Python>
>>> Article.objects.get(pub_date__year=2005, pub_date__month=7, pub_date__day=28)
<Article: Area woman programs in Python>
>>> Article.objects.get(pub_date__week_day=5)
<Article: Area woman programs in Python>
# The "__exact" lookup type can be omitted, as a shortcut.
>>> Article.objects.get(id=1)
<Article: Area woman programs in Python>
>>> Article.objects.get(headline='Area woman programs in Python')
<Article: Area woman programs in Python>
>>> Article.objects.filter(pub_date__year=2005)
[<Article: Area woman programs in Python>]
>>> Article.objects.filter(pub_date__year=2004)
[]
>>> Article.objects.filter(pub_date__year=2005, pub_date__month=7)
[<Article: Area woman programs in Python>]
>>> Article.objects.filter(pub_date__week_day=5)
[<Article: Area woman programs in Python>]
>>> Article.objects.filter(pub_date__week_day=6)
[]
# Django raises an Article.DoesNotExist exception for get() if the parameters
# don't match any object.
>>> Article.objects.get(id__exact=2)
Traceback (most recent call last):
...
DoesNotExist: Article matching query does not exist.
>>> Article.objects.get(pub_date__year=2005, pub_date__month=8)
Traceback (most recent call last):
...
DoesNotExist: Article matching query does not exist.
>>> Article.objects.get(pub_date__week_day=6)
Traceback (most recent call last):
...
DoesNotExist: Article matching query does not exist.
# Lookup by a primary key is the most common case, so Django provides a
# shortcut for primary-key exact lookups.
# The following is identical to articles.get(id=1).
>>> Article.objects.get(pk=1)
<Article: Area woman programs in Python>
# pk can be used as a shortcut for the primary key name in any query
>>> Article.objects.filter(pk__in=[1])
[<Article: Area woman programs in Python>]
# Model instances of the same type and same ID are considered equal.
>>> a = Article.objects.get(pk=1)
>>> b = Article.objects.get(pk=1)
>>> a == b
True
# You can initialize a model instance using positional arguments, which should
# match the field order as defined in the model.
>>> a2 = Article(None, 'Second article', datetime(2005, 7, 29))
>>> a2.save()
>>> a2.id
2L
>>> a2.headline
'Second article'
>>> a2.pub_date
datetime.datetime(2005, 7, 29, 0, 0)
# ...or, you can use keyword arguments.
>>> a3 = Article(id=None, headline='Third article', pub_date=datetime(2005, 7, 30))
>>> a3.save()
>>> a3.id
3L
>>> a3.headline
'Third article'
>>> a3.pub_date
datetime.datetime(2005, 7, 30, 0, 0)
# You can also mix and match position and keyword arguments, but be sure not to
# duplicate field information.
>>> a4 = Article(None, 'Fourth article', pub_date=datetime(2005, 7, 31))
>>> a4.save()
>>> a4.headline
'Fourth article'
# Don't use invalid keyword arguments.
>>> a5 = Article(id=None, headline='Invalid', pub_date=datetime(2005, 7, 31), foo='bar')
Traceback (most recent call last):
...
TypeError: 'foo' is an invalid keyword argument for this function
# You can leave off the value for an AutoField when creating an object, because
# it'll get filled in automatically when you save().
>>> a5 = Article(headline='Article 6', pub_date=datetime(2005, 7, 31))
>>> a5.save()
>>> a5.id
5L
>>> a5.headline
'Article 6'
# If you leave off a field with "default" set, Django will use the default.
>>> a6 = Article(pub_date=datetime(2005, 7, 31))
>>> a6.save()
>>> a6.headline
u'Default headline'
# For DateTimeFields, Django saves as much precision (in seconds) as you
# give it.
>>> a7 = Article(headline='Article 7', pub_date=datetime(2005, 7, 31, 12, 30))
>>> a7.save()
>>> Article.objects.get(id__exact=7).pub_date
datetime.datetime(2005, 7, 31, 12, 30)
>>> a8 = Article(headline='Article 8', pub_date=datetime(2005, 7, 31, 12, 30, 45))
>>> a8.save()
>>> Article.objects.get(id__exact=8).pub_date
datetime.datetime(2005, 7, 31, 12, 30, 45)
>>> a8.id
8L
# Saving an object again doesn't create a new object -- it just saves the old one.
>>> a8.save()
>>> a8.id
8L
>>> a8.headline = 'Updated article 8'
>>> a8.save()
>>> a8.id
8L
>>> a7 == a8
False
>>> a8 == Article.objects.get(id__exact=8)
True
>>> a7 != a8
True
>>> Article.objects.get(id__exact=8) != Article.objects.get(id__exact=7)
True
>>> Article.objects.get(id__exact=8) == Article.objects.get(id__exact=7)
False
# You can use 'in' to test for membership...
>>> a8 in Article.objects.all()
True
# ... but there will often be more efficient ways if that is all you need:
>>> Article.objects.filter(id=a8.id).exists()
True
# dates() returns a list of available dates of the given scope for the given field.
>>> Article.objects.dates('pub_date', 'year')
[datetime.datetime(2005, 1, 1, 0, 0)]
>>> Article.objects.dates('pub_date', 'month')
[datetime.datetime(2005, 7, 1, 0, 0)]
>>> Article.objects.dates('pub_date', 'day')
[datetime.datetime(2005, 7, 28, 0, 0), datetime.datetime(2005, 7, 29, 0, 0), datetime.datetime(2005, 7, 30, 0, 0), datetime.datetime(2005, 7, 31, 0, 0)]
>>> Article.objects.dates('pub_date', 'day', order='ASC')
[datetime.datetime(2005, 7, 28, 0, 0), datetime.datetime(2005, 7, 29, 0, 0), datetime.datetime(2005, 7, 30, 0, 0), datetime.datetime(2005, 7, 31, 0, 0)]
>>> Article.objects.dates('pub_date', 'day', order='DESC')
[datetime.datetime(2005, 7, 31, 0, 0), datetime.datetime(2005, 7, 30, 0, 0), datetime.datetime(2005, 7, 29, 0, 0), datetime.datetime(2005, 7, 28, 0, 0)]
# dates() requires valid arguments.
>>> Article.objects.dates()
Traceback (most recent call last):
...
TypeError: dates() takes at least 3 arguments (1 given)
>>> Article.objects.dates('invalid_field', 'year')
Traceback (most recent call last):
...
FieldDoesNotExist: Article has no field named 'invalid_field'
>>> Article.objects.dates('pub_date', 'bad_kind')
Traceback (most recent call last):
...
AssertionError: 'kind' must be one of 'year', 'month' or 'day'.
>>> Article.objects.dates('pub_date', 'year', order='bad order')
Traceback (most recent call last):
...
AssertionError: 'order' must be either 'ASC' or 'DESC'.
# Use iterator() with dates() to return a generator that lazily requests each
# result one at a time, to save memory.
>>> for a in Article.objects.dates('pub_date', 'day', order='DESC').iterator():
... print repr(a)
datetime.datetime(2005, 7, 31, 0, 0)
datetime.datetime(2005, 7, 30, 0, 0)
datetime.datetime(2005, 7, 29, 0, 0)
datetime.datetime(2005, 7, 28, 0, 0)
# You can combine queries with & and |.
>>> s1 = Article.objects.filter(id__exact=1)
>>> s2 = Article.objects.filter(id__exact=2)
>>> s1 | s2
[<Article: Area woman programs in Python>, <Article: Second article>]
>>> s1 & s2
[]
# You can get the number of objects like this:
>>> len(Article.objects.filter(id__exact=1))
1
# You can get items using index and slice notation.
>>> Article.objects.all()[0]
<Article: Area woman programs in Python>
>>> Article.objects.all()[1:3]
[<Article: Second article>, <Article: Third article>]
>>> s3 = Article.objects.filter(id__exact=3)
>>> (s1 | s2 | s3)[::2]
[<Article: Area woman programs in Python>, <Article: Third article>]
# Slicing works with longs.
>>> Article.objects.all()[0L]
<Article: Area woman programs in Python>
>>> Article.objects.all()[1L:3L]
[<Article: Second article>, <Article: Third article>]
>>> s3 = Article.objects.filter(id__exact=3)
>>> (s1 | s2 | s3)[::2L]
[<Article: Area woman programs in Python>, <Article: Third article>]
# And can be mixed with ints.
>>> Article.objects.all()[1:3L]
[<Article: Second article>, <Article: Third article>]
# Slices (without step) are lazy:
>>> Article.objects.all()[0:5].filter()
[<Article: Area woman programs in Python>, <Article: Second article>, <Article: Third article>, <Article: Article 6>, <Article: Default headline>]
# Slicing again works:
>>> Article.objects.all()[0:5][0:2]
[<Article: Area woman programs in Python>, <Article: Second article>]
>>> Article.objects.all()[0:5][:2]
[<Article: Area woman programs in Python>, <Article: Second article>]
>>> Article.objects.all()[0:5][4:]
[<Article: Default headline>]
>>> Article.objects.all()[0:5][5:]
[]
# Some more tests!
>>> Article.objects.all()[2:][0:2]
[<Article: Third article>, <Article: Article 6>]
>>> Article.objects.all()[2:][:2]
[<Article: Third article>, <Article: Article 6>]
>>> Article.objects.all()[2:][2:3]
[<Article: Default headline>]
# Using an offset without a limit is also possible.
>>> Article.objects.all()[5:]
[<Article: Fourth article>, <Article: Article 7>, <Article: Updated article 8>]
# Also, once you have sliced you can't filter, re-order or combine
>>> Article.objects.all()[0:5].filter(id=1)
Traceback (most recent call last):
...
AssertionError: Cannot filter a query once a slice has been taken.
>>> Article.objects.all()[0:5].order_by('id')
Traceback (most recent call last):
...
AssertionError: Cannot reorder a query once a slice has been taken.
>>> Article.objects.all()[0:1] & Article.objects.all()[4:5]
Traceback (most recent call last):
...
AssertionError: Cannot combine queries once a slice has been taken.
# Negative slices are not supported, due to database constraints.
# (hint: inverting your ordering might do what you need).
>>> Article.objects.all()[-1]
Traceback (most recent call last):
...
AssertionError: Negative indexing is not supported.
>>> Article.objects.all()[0:-5]
Traceback (most recent call last):
...
AssertionError: Negative indexing is not supported.
# An Article instance doesn't have access to the "objects" attribute.
# That's only available on the class.
>>> a7.objects.all()
Traceback (most recent call last):
...
AttributeError: Manager isn't accessible via Article instances
>>> a7.objects
Traceback (most recent call last):
...
AttributeError: Manager isn't accessible via Article instances
# Bulk delete test: How many objects before and after the delete?
>>> Article.objects.all()
[<Article: Area woman programs in Python>, <Article: Second article>, <Article: Third article>, <Article: Article 6>, <Article: Default headline>, <Article: Fourth article>, <Article: Article 7>, <Article: Updated article 8>]
>>> Article.objects.filter(id__lte=4).delete()
>>> Article.objects.all()
[<Article: Article 6>, <Article: Default headline>, <Article: Article 7>, <Article: Updated article 8>]
"""}
from django.conf import settings
building_docs = getattr(settings, 'BUILDING_DOCS', False)
if building_docs or settings.DATABASES[DEFAULT_DB_ALIAS]['ENGINE'] == 'django.db.backends.postgresql':
__test__['API_TESTS'] += """
# In PostgreSQL, microsecond-level precision is available.
>>> a9 = Article(headline='Article 9', pub_date=datetime(2005, 7, 31, 12, 30, 45, 180))
>>> a9.save()
>>> Article.objects.get(id__exact=9).pub_date
datetime.datetime(2005, 7, 31, 12, 30, 45, 180)
"""
if building_docs or settings.DATABASES[DEFAULT_DB_ALIAS]['ENGINE'] == 'django.db.backends.mysql':
__test__['API_TESTS'] += """
# In MySQL, microsecond-level precision isn't available. You'll lose
# microsecond-level precision once the data is saved.
>>> a9 = Article(headline='Article 9', pub_date=datetime(2005, 7, 31, 12, 30, 45, 180))
>>> a9.save()
>>> Article.objects.get(id__exact=9).pub_date
datetime.datetime(2005, 7, 31, 12, 30, 45)
"""
__test__['API_TESTS'] += """
# You can manually specify the primary key when creating a new object.
>>> a101 = Article(id=101, headline='Article 101', pub_date=datetime(2005, 7, 31, 12, 30, 45))
>>> a101.save()
>>> a101 = Article.objects.get(pk=101)
>>> a101.headline
u'Article 101'
# You can create saved objects in a single step
>>> a10 = Article.objects.create(headline="Article 10", pub_date=datetime(2005, 7, 31, 12, 30, 45))
>>> Article.objects.get(headline="Article 10")
<Article: Article 10>
# Edge-case test: A year lookup should retrieve all objects in the given
year, including Jan. 1 and Dec. 31.
>>> a11 = Article.objects.create(headline='Article 11', pub_date=datetime(2008, 1, 1))
>>> a12 = Article.objects.create(headline='Article 12', pub_date=datetime(2008, 12, 31, 23, 59, 59, 999999))
>>> Article.objects.filter(pub_date__year=2008)
[<Article: Article 11>, <Article: Article 12>]
# Unicode data works, too.
>>> a = Article(headline=u'\u6797\u539f \u3081\u3050\u307f', pub_date=datetime(2005, 7, 28))
>>> a.save()
>>> Article.objects.get(pk=a.id).headline
u'\u6797\u539f \u3081\u3050\u307f'
# Model instances have a hash function, so they can be used in sets or as
# dictionary keys. Two models compare as equal if their primary keys are equal.
>>> s = set([a10, a11, a12])
>>> Article.objects.get(headline='Article 11') in s
True
# The 'select' argument to extra() supports names with dashes in them, as long
# as you use values().
>>> dicts = Article.objects.filter(pub_date__year=2008).extra(select={'dashed-value': '1'}).values('headline', 'dashed-value')
>>> [sorted(d.items()) for d in dicts]
[[('dashed-value', 1), ('headline', u'Article 11')], [('dashed-value', 1), ('headline', u'Article 12')]]
# If you use 'select' with extra() and names containing dashes on a query
# that's *not* a values() query, those extra 'select' values will silently be
# ignored.
>>> articles = Article.objects.filter(pub_date__year=2008).extra(select={'dashed-value': '1', 'undashedvalue': '2'})
>>> articles[0].undashedvalue
2
"""
|