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
如果您需要为一些自定义SQL重用查询,还有另一种非常有用的方法。我曾在一个分析应用程序中使用过这种方法,它远远超出了Django的ORM所能轻松完成的范围,所以我将ORM生成的SQL作为子查询包含进来。
from django.db import connection
from myapp.models import SomeModel
queryset = SomeModel.objects.filter(foo='bar')
sql_query, params = queryset.query.as_sql(None, connection)
这将为您提供带有占位符的SQL,以及可以使用的带有查询参数的元组。你可以直接把它传递给DB:
with connection.connection.cursor(cursor_factory=DictCursor) as cursor:
cursor.execute(sql_query, params)
data = cursor.fetchall()
其他回答
从django获取查询结果到数据库(使用正确的参数替换) 你可以使用这个函数:
from django.db import connection
def print_database_query_formatted(query):
sql, params = query.sql_with_params()
cursor = connection.cursor()
cursor.execute('EXPLAIN ' + sql, params)
db_query = cursor.db.ops.last_executed_query(cursor, sql, params).replace('EXPLAIN ', '')
parts = '{}'.format(db_query).split('FROM')
print(parts[0])
if len(parts) > 1:
parts = parts[1].split('WHERE')
print('FROM{}'.format(parts[0]))
if len(parts) > 1:
parts = parts[1].split('ORDER BY')
print('WHERE{}'.format(parts[0]))
if len(parts) > 1:
print('ORDER BY{}'.format(parts[1]))
# USAGE
users = User.objects.filter(email='admin@admin.com').order_by('-id')
print_database_query_formatted(users.query)
输出示例
SELECT "users_user"."password", "users_user"."last_login", "users_user"."is_superuser", "users_user"."deleted", "users_user"."id", "users_user"."phone", "users_user"."username", "users_user"."userlastname", "users_user"."email", "users_user"."is_staff", "users_user"."is_active", "users_user"."date_joined", "users_user"."latitude", "users_user"."longitude", "users_user"."point"::bytea, "users_user"."default_search_radius", "users_user"."notifications", "users_user"."admin_theme", "users_user"."address", "users_user"."is_notify_when_buildings_in_radius", "users_user"."active_campaign_id", "users_user"."is_unsubscribed", "users_user"."sf_contact_id", "users_user"."is_agree_terms_of_service", "users_user"."is_facebook_signup", "users_user"."type_signup"
FROM "users_user"
WHERE "users_user"."email" = 'admin@admin.com'
ORDER BY "users_user"."id" DESC
它基于这个票证评论:https://code.djangoproject.com/ticket/17741#comment:4
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
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)
Django SQL Sniffer是查看(和查看)从Django ORM的任何进程中执行的原始查询的另一种选择。我已经构建了它来满足我所拥有的一个特定用例,我在任何地方都没有看到过,即:
不需要更改目标进程正在执行的源代码(不需要在django设置中注册一个新的应用程序,到处导入装饰器等)。 不更改日志配置(例如,因为我对一个特定的进程感兴趣,而不是配置应用的整个进程群) 不需要重新启动目标进程(例如,因为它是一个重要的组件,重新启动可能会导致一些停机时间)
因此,Django SQL Sniffer可以特别使用,并附加到已经运行的进程。然后,该工具“嗅探”已执行的查询,并在执行时将它们打印到控制台。当工具停止时,将显示一个统计摘要,其中包含基于某些可能的度量(计数、最大持续时间和总组合持续时间)的异常值查询。
这是我附加到Python shell的示例的截图
你可以在github页面上查看现场演示和更多细节。
我相信这应该工作,如果你使用PostgreSQL:
from django.db import connections
from app_name import models
from django.utils import timezone
# Generate a queryset, use your favorite filter, QS objects, and whatnot.
qs=models.ThisDataModel.objects.filter(user='bob',date__lte=timezone.now())
# Get a cursor tied to the default database
cursor=connections['default'].cursor()
# Get the query SQL and parameters to be passed into psycopg2, then pass
# those into mogrify to get the query that would have been sent to the backend
# and print it out. Note F-strings require python 3.6 or later.
print(f'{cursor.mogrify(*qs.query.sql_with_params())}')
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