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
我把这个函数放在我项目中的一个应用程序的util文件中:
import logging
import re
from django.db import connection
logger = logging.getLogger(__name__)
def sql_logger():
logger.debug('TOTAL QUERIES: ' + str(len(connection.queries)))
logger.debug('TOTAL TIME: ' + str(sum([float(q['time']) for q in connection.queries])))
logger.debug('INDIVIDUAL QUERIES:')
for i, query in enumerate(connection.queries):
sql = re.split(r'(SELECT|FROM|WHERE|GROUP BY|ORDER BY|INNER JOIN|LIMIT)', query['sql'])
if not sql[0]: sql = sql[1:]
sql = [(' ' if i % 2 else '') + x for i, x in enumerate(sql)]
logger.debug('\n### {} ({} seconds)\n\n{};\n'.format(i, query['time'], '\n'.join(sql)))
然后,当需要时,我只是导入它,并从任何上下文(通常是视图)调用它是必要的,例如:
# ... other imports
from .utils import sql_logger
class IngredientListApiView(generics.ListAPIView):
# ... class variables and such
# Main function that gets called when view is accessed
def list(self, request, *args, **kwargs):
response = super(IngredientListApiView, self).list(request, *args, **kwargs)
# Call our function
sql_logger()
return response
在模板之外这样做很好,因为如果你有API视图(通常是Django Rest框架),它也适用于模板。
其他回答
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。
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
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>
from django.db import reset_queries, connection
class ShowSQL(object):
def __enter__(self):
reset_queries()
return self
def __exit__(self, *args):
for sql in connection.queries:
print('Time: %s\nSQL: %s' % (sql['time'], sql['sql']))
然后你可以使用:
with ShowSQL() as t:
some queries <select>|<annotate>|<update> or other
它打印
时间:% s SQL: % s
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)