是否有一种方法可以在执行查询时显示Django正在运行的SQL ?
当前回答
django扩展有一个带参数print-sql的命令shell_plus
./manage.py shell_plus --print-sql
在django-shell中,所有执行的查询都会被打印出来
Ex.:
User.objects.get(pk=1)
SELECT "auth_user"."id",
"auth_user"."password",
"auth_user"."last_login",
"auth_user"."is_superuser",
"auth_user"."username",
"auth_user"."first_name",
"auth_user"."last_name",
"auth_user"."email",
"auth_user"."is_staff",
"auth_user"."is_active",
"auth_user"."date_joined"
FROM "auth_user"
WHERE "auth_user"."id" = 1
Execution time: 0.002466s [Database: default]
<User: username>
其他回答
使用django.db.connection.queries查看查询
from django.db import connection
print(connection.queries)
访问QuerySet对象上的原始SQL查询
qs = MyModel.objects.all()
print(qs.query)
在django中,如果你有这样的查询:
MyModel.objects.all()
do:
MyModel.objects.all().query.sql_with_params()
or:
str(MyModel.objects.all().query)
来获取SQL字符串
没有其他答案涵盖这个方法,所以:
我发现迄今为止最有用、最简单、最可靠的方法是询问您的数据库。例如,在Linux的Postgres上,你可能会这样做:
sudo su postgres
tail -f /var/log/postgresql/postgresql-8.4-main.log
每个数据库的过程略有不同。在数据库日志中,你不仅可以看到原始SQL,还可以看到django在系统上设置的任何连接或事务开销。
为CREATE / UPDATE / DELETE /命令生成SQL,这在Django中是即时的
from django.db.models import sql
def generate_update_sql(queryset, update_kwargs):
"""Converts queryset with update_kwargs
like : queryset.update(**update_kwargs) to UPDATE SQL"""
query = queryset.query.clone(sql.UpdateQuery)
query.add_update_values(update_kwargs)
compiler = query.get_compiler(queryset.db)
sql, params = compiler.as_sql()
return sql % params
from django.db.models import sql
def generate_delete_sql(queryset):
"""Converts select queryset to DELETE SQL """
query = queryset.query.chain(sql.DeleteQuery)
compiler = query.get_compiler(queryset.db)
sql, params = compiler.as_sql()
return sql % params
from django.db.models import sql
def generate_create_sql(model, model_data):
"""Converts queryset with create_kwargs
like if was: queryset.create(**create_kwargs) to SQL CREATE"""
not_saved_instance = model(**model_data)
not_saved_instance._for_write = True
query = sql.InsertQuery(model)
fields = [f for f in model._meta.local_concrete_fields if not isinstance(f, AutoField)]
query.insert_values(fields, [not_saved_instance], raw=False)
compiler = query.get_compiler(model.objects.db)
sql, params = compiler.as_sql()[0]
return sql % params
测试和使用
def test_generate_update_sql_with_F(self):
qs = Event.objects.all()
update_kwargs = dict(description=F('slug'))
result = generate_update_sql(qs, update_kwargs)
sql = "UPDATE `api_event` SET `description` = `api_event`.`slug`"
self.assertEqual(sql, result)
def test_generate_create_sql(self):
result = generate_create_sql(Event, dict(slug='a', app='b', model='c', action='e'))
sql = "INSERT INTO `api_event` (`slug`, `app`, `model`, `action`, `action_type`, `description`) VALUES (a, b, c, e, , )"
self.assertEqual(sql, result)
我为此开发了一个扩展,所以你可以很容易地在你的视图函数上放一个装饰器,看看有多少查询被执行了。
如何安装:
$ pip install django-print-sql
用作上下文管理器:
from django_print_sql import print_sql
# set `count_only` to `True` will print the number of executed SQL statements only
with print_sql(count_only=False):
# write the code you want to analyze in here,
# e.g. some complex foreign key lookup,
# or analyzing a DRF serializer's performance
for user in User.objects.all()[:10]:
user.groups.first()
装饰:用作装饰:
from django_print_sql import print_sql_decorator
@print_sql_decorator(count_only=False) # this works on class-based views as well
def get(request):
# your view code here
Github: https://github.com/rabbit-aaron/django-print-sql
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