I'm willing to create queryset list template in the admin
The queryset is obtained through a cursor.execute() so a fake model might be needed is needed.
Basically I just want to take advantage of the pagination and filter functionality Django admin list provides.
Here's the relevant part of my code
models.py
class Query(object):
def __init__(self, sql):
self.sql = sql
def execute_query(self):
cursor = connection.cursor()
start_time = time()
try:
cursor.execute(self.sql)
except DatabaseError as e:
cursor.close()
raise e
return cursor, ((time() - start_time) * 1000)
admin.py
class QueryAdmin(admin.ModelAdmin):
....
admin.site.register(Query, QueryAdmin)
I have just implemented this feature. You need new View RawChangeList
extending ChangeList
View from Django:
from django.contrib.admin.views.main import ChangeList
from django.db import connections
class RawChangeList(ChangeList):
"""
Extended Django ChangeList to be able show data from RawQueryset.
"""
def get_count(self):
connection = connections[self.queryset.db]
with connection.cursor() as c:
if connection.vendor == 'microsoft': # CTE in subquery is not working in SQL Server
c.execute(self.queryset.raw_query)
c.execute('SELECT @@ROWCOUNT')
else:
query = 'SELECT COUNT(*) FROM ({query}) AS sq'
c.execute(query.format(query=self.queryset.raw_query))
return c.fetchone()[0]
def get_queryset_slice(self):
connection = connections[self.queryset.db]
if connection.vendor == 'microsoft':
# SQL Server needs ordered query for slicing
if hasattr(self.queryset, 'ordered') and self.queryset.ordered:
query = '{query}'
else:
query = '{query} ORDER BY 1'
query += ' OFFSET {offset} ROWS FETCH NEXT {limit} ROWS ONLY'
else:
query = '{query} LIMIT {limit} OFFSET {offset}'
return self.queryset.model.objects.raw(
query.format(
query=self.queryset.raw_query,
offset=self.page_num * self.list_per_page,
limit=(self.page_num + 1) * self.list_per_page - self.page_num * self.list_per_page,
)
)
def get_queryset(self, request):
"""
Overriding to avoid applying filters in ChangeList because RawQueryset has not filter method.
So any filters has to be applied manually for now.
"""
qs = self.root_queryset
if not hasattr(qs, 'count'):
qs.count = lambda: self.get_count()
return qs
def get_results(self, request):
if self.show_all:
qs = self.queryset
else:
qs = self.get_queryset_slice()
paginator = self.model_admin.get_paginator(request, self.queryset, self.list_per_page)
self.result_count = paginator.count
self.show_full_result_count = False
self.show_admin_actions = True
self.full_result_count = 0
self.result_list = list(qs)
self.can_show_all = True
self.multi_page = True
self.paginator = paginator
And then use this RawChangeList
in admin:
@admin.register(MyModel)
class MyModelAdmin(admin.ModelAdmin):
def get_changelist(self, request, **kwargs):
return RawChangeList
def get_queryset(self, request):
return MyModel.objects.raw('SELECT * FROM my_app_my_model')
def get_object(self, request, object_id, from_field=None):
return MyModel.objects.raw('SELECT * FROM my_app_my_model WHERE id=%s', (object_id, ))[0]
If you are just trying to use the django admin functionality to make use of it's pagination and filtering features, you will find yourself spending far more time on it than you would if you used django pagination . In the the very first thing you will find is that both pagination and filtering will not work with cursor.execute
If you do need some sort of admin functionality here, read on.
The preferred way to use a custom queryset in django admin is to override the get_queryset method in the admin class.
The get_queryset method on a ModelAdmin returns a QuerySet of all model instances that can be edited by the admin site. One use case for overriding this method is to show objects owned by the logged-in user:
So our code would be like
class QueryAdmin(admin.ModelAdmin):
def queryset(self, request, queryset):
return SomeModel.objects.raw('SOME QUERY')
If you wanted to return a custom raw query set, you would do that here by using the raw method call on the object's manager. It's much more preferable to using cursor.execute
. You will actually need such a method (objects.raw) instead of execute to make use of some of the django admin functionality.
Even now you will find that pagination doesn't work. Then you will need to do this: django pagination and RawQuerySet
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