blocks|key|1330350|text|您不能使用get_or_create+(甚至是create)进行像样的批量插入，而且也没有可以轻松做到这一点的应用编程接口。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1330351|如果您的表足够简单，使用原始SQL创建行并不是一件很麻烦的事情，那么它就不会太难；例如：|1330352|INSERT+INTO+site_entry+(field1,+field2)
(
+++++++++SELECT+i.field1,+i.field2
+++++++++FROM+(VALUES+%25s)+AS+i(field1,+field2)
+++++++++LEFT+JOIN+site_entry+as+existing
+++++++++++++++++ON+(existing.field1+=+i.field1+AND+existing.field2+=+i.field2)
+++++++++WHERE+existing.id+IS+NULL
)|code-block|syntax|javascript|1330353|其中%25s是一个类似于("field1,+field2"),+("field3,+field4"),+("field5,+field6")的字符串，您必须自己创建并正确转义。|offset|length|style|CODE|1330354|entityMap^0|0|0|0|A|1M|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|R|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|S|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|T|8|@$K|U|L|V|M|N]]|9|@]|A|$]]|$1|O|3|-4|5|6|7|W|8|@]|9|@]|A|$]]]|P|$]]

You can't do decent bulk insertions with get_or_create (or even create), and there's no API for doing this easily.

If your table is simple enough that creating rows with raw SQL isn't too much of a pain, it's not too hard; something like:

<pre><code>INSERT INTO site_entry (field1, field2)
(
 SELECT i.field1, i.field2
 FROM (VALUES %s) AS i(field1, field2)
 LEFT JOIN site_entry as existing
 ON (existing.field1 = i.field1 AND existing.field2 = i.field2)
 WHERE existing.id IS NULL
)
</code></pre>

where %s is a string like <code>("field1, field2"), ("field3, field4"), ("field5, field6")</code> that you'll have to create and escape properly yourself.

blocks|key|1330104|text|这取决于你的目标是什么。您可以使用manage.py的loaddata函数以适当的格式(JSON、XML、YAML等)加载数据。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1330105|另请参见this+discussion。|1330106|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.djangoproject.com/en/dev/ref/django-admin/#loaddata|1|http://www.pubbs.net/django/200908/42073/^0|H|9|R|8|R|8|0|0|4|F|1|0^^$0|@$1|2|3|4|5|6|7|R|8|@$9|S|A|T|B|C]|$9|U|A|V|B|C]]|D|@$9|W|A|X|1|Y]]|E|$]]|$1|F|3|G|5|6|7|Z|8|@]|D|@$9|10|A|11|1|12]]|E|$]]|$1|H|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|I|$J|$5|K|L|M|E|$N|O]]|P|$5|K|L|M|E|$N|Q]]]]

Depends on what you are aiming at. You can use <code>manage.py</code>'s <a href="https://docs.djangoproject.com/en/dev/ref/django-admin/#loaddata" rel="nofollow noreferrer"><code>loaddata</code></a> function to load data in a appropriate format (JSON, XML, YAML,...).

See also <a href="http://www.pubbs.net/django/200908/42073/" rel="nofollow noreferrer">this discussion</a>.

blocks|key|1115306|text|从1.4开始，您可以使用bulk_create|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1115307|请参阅the+docs|offset|length|1115308|*注意注意事项(最重要的一点是不会调用模型的save()方法，因此不会发送pre_save和post_save信号)*|1115309|entityMap|0|LINK|mutability|MUTABLE|url|https://docs.djangoproject.com/en/dev/ref/models/querysets/#django.db.models.query.QuerySet.bulk_create^0|0|3|8|0|0|0^^$0|@$1|2|3|4|5|6|7|P|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|Q|8|@]|9|@$D|R|E|S|1|T]]|A|$]]|$1|F|3|G|5|6|7|U|8|@]|9|@]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$J|$5|K|L|M|A|$N|O]]]]

Since 1.4 you can do bulk_create

See <a href="https://docs.djangoproject.com/en/dev/ref/models/querysets/#django.db.models.query.QuerySet.bulk_create" rel="nofollow">the docs</a>

*Do pay attention to the caveats though (most important one being that the model’s save() method will not be called, and thus the pre_save and post_save signals will not be sent.) *

blocks|key|1115017|text|我会说没有。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1115018|但是我想知道你的item是什么类型的，如果它们有field1和field2属性的话。看起来存在另一个表示条目的类，但不是从models.Model派生的。也许您可以省略这个类，立即创建Entry实例，而不是创建那些项。|offset|length|style|CODE|1115019|entityMap^0|0|8|4|O|6|V|6|1P|C|2K|5|0^^$0|@$1|2|3|4|5|6|7|J|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|K|8|@$D|L|E|M|F|G]|$D|N|E|O|F|G]|$D|P|E|Q|F|G]|$D|R|E|S|F|G]|$D|T|E|U|F|G]]|9|@]|A|$]]|$1|H|3|-4|5|6|7|V|8|@]|9|@]|A|$]]]|I|$]]

I'd say there isn't. 

But I wonder what type your <code>item</code>s are, if they have <code>field1</code> and <code>field2</code> as attributes. Looks like there exists another class representing an entry but is not derived from <code>models.Model</code>. Maybe you can omit this class and create <code>Entry</code> instances immediately instead of creating those items.

blocks|key|1330253|text|如果您不确定item_list中的内容是否已经存在于DB中，并且需要模型对象，那么get_or_create绝对是最佳选择。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1330254|如果你知道这些项目不在你的数据库中，你最好这样做：|1330255|for+item+in+item_list:
++++new+=+Entry.objects.create(
++++++++field1+=+item.field1,
++++++++field2+=+item.field2,
++++)|code-block|syntax|javascript|1330256|如果你不需要这些对象，那么就忽略函数调用的返回。它不会加快数据库的速度，但如果这是一个问题，它将有助于内存管理。|1330257|如果您不确定数据是否已经在数据库中，但是任何一个字段都有unique=True标志，那么DB将强制执行唯一性，您只需捕获异常并继续操作即可。这将通过避免尝试选择现有对象来防止额外的DB命中。|1330258|from+django.db+import+IntegrityError

for+item+in+item_list:
++++try:
++++++++new+=+Entry.objects.create(
++++++++++++field1+=+item.field1,
++++++++++++field2+=+item.field2,
++++++++)
++++except+IntegrityError:
++++++++continue|1330259|在这两种情况下，您都可以通过手动管理事务来提高速度。Django将为每次保存自动创建和提交一个事务，但提供了一些装饰器，如果您知道您将在特定函数中执行大量的DB保存，这些装饰器将极大地提高效率。在解释这一切方面，Django文档比我在这里做得更好，但是您可能需要特别关注django.db.transaction.commit_on_success|1330260|entityMap|0|LINK|mutability|MUTABLE|url|http://docs.djangoproject.com/en/1.1/topics/db/transactions/#django-db-transaction-commit-on-success^0|6|9|15|D|0|0|0|0|S|B|0|0|3R|13|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@$9|13|A|14|B|C]|$9|15|A|16|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|17|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|18|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|19|8|@]|D|@]|E|$]]|$1|O|3|P|5|6|7|1A|8|@$9|1B|A|1C|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|J|7|1D|8|@]|D|@]|E|$K|L]]|$1|S|3|T|5|6|7|1E|8|@]|D|@$9|1F|A|1G|1|1H]]|E|$]]|$1|U|3|-4|5|6|7|1I|8|@]|D|@]|E|$]]]|V|$W|$5|X|Y|Z|E|$10|11]]]]

If you're not sure whether the things in your <code>item_list</code> already exist in your DB, and you need the model objects, then <code>get_or_create</code> is definitely the way to go. 

If you know the items are NOT in your DB, you would be much better doing:

<pre><code>for item in item_list:
 new = Entry.objects.create(
 field1 = item.field1,
 field2 = item.field2,
 )
</code></pre>

And if you don't need the objects, then just ignore the return from the function call. It won't speed the DB stuff, but it will help with memory management if that's an issue.

If you're not sure whether the data is already in the DB, but either field has a <code>unique=True</code> flag on it, then the DB will enforce the uniqueness, and you can just catch the exception and move on. This will prevent an extra DB hit by avoiding the attempt to select the existing object.

<pre><code>from django.db import IntegrityError

for item in item_list:
 try:
 new = Entry.objects.create(
 field1 = item.field1,
 field2 = item.field2,
 )
 except IntegrityError:
 continue
</code></pre>

You could increase speed in either case by manually managing the transactions. Django will automatically create and commit a transaction for every save, but provides some decorators that will greatly increase efficiency if you know you'll be doing a lot of DB saves in a particular function. The Django docs do a better job of explaining all of this than I can here, but you'll probably want to pay particular attention to <a href="http://docs.djangoproject.com/en/1.1/topics/db/transactions/#django-db-transaction-commit-on-success" rel="nofollow noreferrer">django.db.transaction.commit_on_success</a>

Is there a more efficient way for doing this?

<pre><code>for item in item_list:
 e, new = Entry.objects.get_or_create(
 field1 = item.field1,
 field2 = item.field2,
 )
</code></pre>

Efficient way to bulk insert with get_or_create() in Django (SQL, Python, Django)

内存管理

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有没有更有效的方法来做到这一点？for item in item_list:    e, new = Entry.objects.get_or_create(        field1 = item.field1,        field2 = item.field2,    )

问在Django中使用get_or_create()进行大容量插入的有效方法
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