compare two querysets

[Sells, Fred]

I’ve got a use case where I need to find the fields that are different between two querysets in the same model and then use those fields to modify another queryset in that model.  The first two represent “masks” of allowed fields for a specific version while the third is the actual data.  Assessment_id’s below 1000 are templates while >1000 are data.

 

Based on a date entered in one field (not shown) the version of the form could change and thus the applicable sections could change.  This will not happen often and therefore does not need to be efficient.    There will be cases where the all the fields in the templates are identical, but it may not be practical to merge those templates due to the need to find/fix design bugs and requirements changes in template definitions.  

 

The best idea I can come up with is to:

                Get a queryset for each template based on it’s pk (derived elsewhere)

                Convert the __dict__ from each queryset to a set of (name,value) pairs.

                Find the differences between the two sets

                Convert the remaining set back to a dict() called “changes”

                Data = get the queryset for the actual data using it’s pk

                Use Data.__dict__( changes)

                And of course save

 

Snippets of models module below:

 

class MDSSection(models.Model):

    assessment     = models.OneToOneField(Assessment, primary_key=True)

    . . .

 

class A(MDSSections):

    A0100A    = models.CharField(max_length=10, help_text='''Text      :  Facility National Provider Identifier (NPI)''')

    A0100B    = models.CharField(max_length=12, help_text='''Text      :  Facility CMS Certification Number (CCN)''')

    A0100C    = models.CharField(max_length=15, help_text='''Text      :  State provider number''')

    A0200     = models.CharField(max_length= 1, default='1', help_text='''Code      :  Type of provider''')

    A0310A    = models.CharField(max_length= 2, help_text='''Code      :  Type of assessment: OBRA''')

                . . .