这是执行仍然通过 Django 的 ORM 的批量插入的方法（因此保留了 ORM 提供的许多好处）。这种方法包括继承 InsertQuery 类以及创建一个自定义管理器，该管理器准备模型实例以插入数据库，其方式与 Django 的 save() 方法使用的方式非常相似。下面的 BatchInsertQuery 类的大部分代码直接来自 InsertQuery 类，只添加或修改了几行关键行。要使用 batch_insert 方法，请传入一组要插入数据库的模型实例。这种方法使视图中的代码不必担心将模型实例转换为有效的 SQL 值；管理器类与 BatchInsertQuery 类一起处理该问题。
from django.db import models, connection
from django.db.models.sql import InsertQuery
class BatchInsertQuery( InsertQuery ):
####################################################################
def as_sql(self):
"""
Constructs a SQL statement for inserting all of the model instances
into the database.
Differences from base class method:
- The VALUES clause is constructed differently to account for the
grouping of the values (actually, placeholders) into
parenthetically-enclosed groups. I.e., VALUES (a,b,c),(d,e,f)
"""
qn = self.connection.ops.quote_name
opts = self.model._meta
result = ['INSERT INTO %s' % qn(opts.db_table)]
result.append('(%s)' % ', '.join([qn(c) for c in self.columns]))
result.append( 'VALUES %s' % ', '.join( '(%s)' % ', '.join(
values_group ) for values_group in self.values ) ) # This line is different
params = self.params
if self.return_id and self.connection.features.can_return_id_from_insert:
col = "%s.%s" % (qn(opts.db_table), qn(opts.pk.column))
r_fmt, r_params = self.connection.ops.return_insert_id()
result.append(r_fmt % col)
params = params + r_params
return ' '.join(result), params
####################################################################
def insert_values( self, insert_values ):
"""
Adds the insert values to the instance. Can be called multiple times
for multiple instances of the same model class.
Differences from base class method:
-Clears self.columns so that self.columns won't be duplicated for each
set of inserted_values.
-appends the insert_values to self.values instead of extends so that
the values (actually the placeholders) remain grouped separately for
the VALUES clause of the SQL statement. I.e., VALUES (a,b,c),(d,e,f)
-Removes inapplicable code
"""
self.columns = [] # This line is new
placeholders, values = [], []
for field, val in insert_values:
placeholders.append('%s')
self.columns.append(field.column)
values.append(val)
self.params += tuple(values)
self.values.append( placeholders ) # This line is different
########################################################################
class ManagerEx( models.Manager ):
"""
Extended model manager class.
"""
def batch_insert( self, *instances ):
"""
Issues a batch INSERT using the specified model instances.
"""
cls = instances[0].__class__
query = BatchInsertQuery( cls, connection )
for instance in instances:
values = [ (f, f.get_db_prep_save( f.pre_save( instance, True ) ) ) \
for f in cls._meta.local_fields ]
query.insert_values( values )
return query.execute_sql()
########################################################################
class MyModel( models.Model ):
myfield = models.CharField(max_length=255)
objects = ManagerEx()
########################################################################
# USAGE:
object1 = MyModel(myfield="foo")
object2 = MyModel(myfield="bar")
object3 = MyModel(myfield="bam")
MyModels.objects.batch_insert(object1,object2,object3)