Queries

Django documentation

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get()

This method returns a single object that matches the given lookup parameters. If there is no match, it raises a DoesNotExist exception.

# Get an object with primary key 1
my_object = MyModel.objects.get(pk=1)

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filter()

This method returns a queryset that contains all objects that match the given lookup parameters.

# Get all objects where the field 'my_field' is equal to 'my_value'
my_objects = MyModel.objects.filter(my_field='my_value')

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exclude()

This method returns a queryset that excludes all objects that match the given lookup parameters.

# Get all objects where the field 'my_field' is not equal to 'my_value'
my_objects = MyModel.objects.exclude(my_field='my_value')

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all()

This method returns a queryset that contains all objects in the database.

# Get all objects in the database
my_objects = MyModel.objects.all()

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order_by()

This method returns a queryset that is sorted based on the given field(s).

# Get all objects sorted by the field 'my_field'
my_objects = MyModel.objects.order_by('my_field')

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values()

This method returns a queryset that contains a dictionary of values for the specified fields.

# Get a queryset containing dictionaries of values for the fields 'my_field_1' and 'my_field_2'
my_values = MyModel.objects.values('my_field_1', 'my_field_2')

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annotate()

This method adds a calculated field to each object in the queryset.

from django.db.models import Count
    
# Add a calculated field 'my_field_count' to each object in the queryset,
# containing the count of related objects in a related model
my_annotated_objects = MyModel.objects.annotate(my_field_count=Count('related_model'))

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count()

This method returns the number of objects that match the given lookup parameters.

# Get the number of objects where the field 'my_field' is equal to 'my_value'
my_object_count = MyModel.objects.filter(my_field='my_value').count()

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exists()

This method returns a boolean value indicating whether there is at least one object that matches the given lookup parameters.

# Check if there is at least one object where the field 'my_field' is equal to 'my_value'
my_objects_exist = MyModel.objects.filter(my_field='my_value').exists()

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distinct()

This method returns a queryset that contains only unique values for the specified fields.

# Get a queryset containing distinct values for the field 'my_field'
my_distinct_values = MyModel.objects.values_list('my_field', flat=True).distinct()

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update()

This method updates one or more fields for all objects that match the given lookup parameters.

# Update the field 'my_field' to 'my_new_value' for all objects where the field 'my_other_field' is equal to 'my_other_value'
MyModel.objects.filter(my_other_field='my_other_value').update(my_field='my_new_value')

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delete()

This method deletes all objects that match the given lookup parameters.

# Delete all objects where the field 'my_field' is equal to 'my_value'
    MyModel.objects.filter(my_field='my_value').delete()

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aggregate()

This method returns a dictionary of calculated values for the specified fields.

from django.db.models import Avg
    
# Get a dictionary containing the average value of the field 'my_field'
my_aggregate = MyModel.objects.aggregate(avg_my_field=Avg('my_field'))

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first()

This method returns the first object that matches the given lookup parameters, based on the ordering of the queryset.

# Get the first object in the queryset where the field 'my_field' is equal to 'my_value',
# based on the ordering of the queryset
my_first_object = MyModel.objects.filter(my_field='my_value').order_by('my_ordering_field').first()

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last()

This method returns the last object that matches the given lookup parameters, based on the ordering of the queryset.

# Get the last object in the queryset where the field 'my_field' is equal to 'my_value',
# based on the ordering of the queryset
my_last_object = MyModel.objects.filter(my_field='my_value').order_by('my_ordering_field').last()

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