I am using cursor.execute to run a raw sql query. The return type is a list of tuples. This throws Attribute error. Is there a way to convert this to or receive as a queryset??
You should select pk list:
queryset = model.objects.filter(pk__in=pk_list)
It is important that it won't keep the original ordering.
Related
I have a cosmos db collection. I need to query all documents and return them in order of creation date. Creation date is a defined field but for historical reason it is in string format as MM/dd/yyyy. For example: 02/09/2019. If I just order by this string, the result is chaos.
I am using linq lambda to write my query in webapi. I have tried to parse the string and try to convert the string. Both returned "method not supported".
Here is my query:
var query = Client.CreateDocumentQuery<MyModel>(CollectionLink)
.Where(f => f.ModelType == typeof(MyModel).Name.ToLower() && f.Language == getMyModelsRequestModel.Language )
.OrderByDescending(f => f.CreationDate)
.AsDocumentQuery();
Appreciate for any advice. Thanks. It will be huge effort to go back and modify the format of the field (which affects many other things). I wish to avoid it if possible.
Chen Wang.Since the order by does not support derived values or sub query(link),so you need to sort the derived values by yourself i think.
You could construct the MM/dd/yyyy to yyyymmdd by UDF in cosmos db.
udf:
function getValue(datetime){
return datetime.substring(6,10)+datetime.substring(0,2)+datetime.substring(3,5);
}
sql:
SELECT udf.getValue(c.time) as time from c
Then you could sort the array by property value of class in c# code.Please follow this case:How to sort an array containing class objects by a property value of a class instance?
My views.py contains a view like:
class RankViewSet(generics.mixins.CreateModelMixin,
generics.mixins.ListModelMixin,
viewsets.GenericViewSet):
def get_queryset(self):
with connection.cursor() as cursor:
query = "SELECT ... "
cursor.execute(query)
row = cursor.fetchall()
return row
Here, get_queryset(self) returns some tuples like following:
((name1, college1, semester1), (name2, college2, semester2), (name3, college3, semester3), ...)
All of the fields are from different models, so I have to fetch these data using raw sql. How can I serialize this tuple in django rest framework? Or Is there any way to convert tuple in queryset?
Only just seen this question but answer may still be useful...
Off the top of my head you have a few options:
serializers.ListField -as you basically have a list of lists, if the content is all the same type you can do child=serializers.ListField(child=serializers.CharField())
serializers.SerializerMethodField()..and call mySerialiser(many=True) with the set
name = serializers.SerializerMethodField()
def get_name(self, obj):
return obj[0]
Having said this unless you have a very specific reason to use a raw sql query, as you are using django you should take advantage of its ORM engine and then you can use rest_framework model serializer. If speed is an issue you can use .only() and .defer() with your queries.
I have a model Form for table forms. There is a column called guid which can be null, or contain some sort of grouping random hash.
I need to select all forms that have column guid either null or unique in current search. In other words, for repeating guid values in current search I select only first occurence of every guid hash.
I tried:
$results = App\Form::where(... some where clauses .. ).groupBy('guid')
and it's almost ok, but for all rows, where guid == NULL it groups them and selects only one (and I need all of them).
How can I get the unique or null rows either by building proper SQL query or filtering the results in PHP?
Note: I need my $results to be an Illuminate\Database\Eloquent\Builder instance
EDIT:
I fount out that SQL version of query I need is:
SELECT * FROM `forms` WHERE .... GROUP BY IFNULL(guid, id)
What would be equivallent query for Laravel's database query builder?
UPDATE: Using DB::raw
App\Form::where(... conditions ...)
->groupBy(DB::raw("IFNULL('guid', 'id')"));
Or the another way could be:
You can also use whereNotNull, whereNull & at last merge both the collections using merge() like this:
First get the results where guid is grouped by (excluding null guid's here):
$unique_guid_without_null = App\Form::whereNotNull('guid')->groupBy('guid')->get();
Now, get the results where guid is null:
$all_guid_with_null = App\Form::whereNull('guid')->get();
and at last merge both the collections using merge() method:
$filtered_collection = $unique_guid_without_null->merge($all_guid_with_null);
Hope this helps!
For your edited question, you can use raw() as;
->groupBy(DB::raw("IFNULL('guid', 'id')"))
So your final query will be as:
$results = App\Form::where(... some where clauses .. )
->groupBy(DB::raw("IFNULL('guid', 'id')"));
By above query, your $results will be an instance of Illuminate\Database\Eloquent\Builder.
I need to get an array of integers, which will contain raw ids of Eloquent records. The following query
Quote::select('id')->get();
gets an eloquent collection instead of an array of integers. How to modify it, so it meets my requirements?
Try this code:
Quote::get(['id'])->toArray();
Or:
Quote::all(['id'])->toArray();
Or:
DB::table('quote')->select('id')->get()->toArray();
Or:
Quote::pluck('id')->toArray();
in my Spring MVC project i m using Hibernate, by using Criteria API i am applying Group BY and Order BY clause. Query get executed on DB successfully and it brings result also but its an array of Object--
Here is code of Criteria API
Criteria criteria = session.createCriteria(DashboardSubindicatorSubmission.class, "DashboardSubindicatorSubmission")
.setProjection(Projections.projectionList()
.add(Projections.sum("InputValue").as("InputValue"))
.add(Projections.groupProperty("fkAccademicYearId"))
.add(Projections.groupProperty("fkAssessmentPlanID"))
.add(Projections.groupProperty("fkSubindicatorID"))
.add(Projections.groupProperty("InputTitle")))
.addOrder(Order.asc("fkAccademicYearId"))
.addOrder(Order.asc("fkAssessmentPlanID"))
.addOrder(Order.asc("InputTitle"));
List<DashboardSubindicatorSubmission> dashboardSubindicatorSubmissionList = (List<DashboardSubindicatorSubmission>)criteria.list();
session.flush();
transaction.commit();
return dashboardSubindicatorSubmissionList;
I am casting criteria.list() to List<DashboardSubindicatorSubmission> but when i try to do dashboardSubindicatorSubmissionList.get(i) on controller it gives me exception java.lang.ClassCastException: [Ljava.lang.Object; cannot be cast to mkcl.accreditation.model.DashboardSubindicatorSubmission.
i come to know that, though i m casting it to List<DashboardSubindicatorSubmission> still its an list of object[] thats why i cant do dashboardSubindicatorSubmissionList.get(i) because it returns me object of DashboardSubindicatorSubmission. (Correct me if i am wrong)
So how can i convert my result into list of DashboardSubindicatorSubmission class?
Does setResultTransformer() helps me in this case?
You have two options. When you use projections, Hibernate doesn't know how to respect each field because it uses the name of each field to build objects and he doesn't know the names yet.
Thus, your first option is to name the fields grouped so that they match the names of object properties. This is necessary even if the string you use in projection is already the name of the object field. Something like:
.add(Projections.groupProperty("fkAccademicYearId"), "fkAccademicYearId") // same value
.add(Projections.groupProperty("fkAssessmentPlanID"), "other") // other value
The second option is to do what you yourself suggested, create your own implementation of ResultTransformer. I reckon this a interesting option if you want to extract other object of this query, as when you make a report.