edc-reference 0.1.20

Pivoted reference model for clinicedc/edc modules

|pypi| |travis| |coverage|


edc-reference
-------------

Pivoted reference table for EDC modules

``edc_reference`` creates a pivoted table of CRF and Requisition records with a small subset of values that can be efficiently referenced. The module is used by ``edc_metadata_rules`` to quickly determine if a CRF or Requisition model instance exists avoiding the need to query each individual model class.

See also ``edc_metadata_rules``


Usage and Configuration
=======================

Declare a model with the ``ReferenceModelMixin``.

.. code-block:: python

from edc_reference.model_mixins import ReferenceModelMixin

class CrfOne(ReferenceModelMixin, BaseUuidModel):

subject_visit = models.ForeignKey(SubjectVisit, on_delete=PROTECT)

report_datetime = models.DateTimeField(default=get_utcnow)

f1 = models.CharField(max_length=50)

f2 = models.CharField(max_length=50)

f3 = models.CharField(max_length=50)

f4 = models.DatetimeField(null=True)


Register the model and the relevant fields with the site global, ``site_reference_configs``:

.. code-block:: python

from edc_reference.site import ReferenceModelConfig

reference = ReferenceModelConfig(
model='edc_reference.crfone',
fields=['f1', 'f4'])
site_reference_configs.register(reference)

Create a model instance:

.. code-block:: python

crf_one = CrfOne.objects.create(
subject_visit=subject_visit,
f1='happiness'
f4=get_utcnow())

The ``Reference`` model will be updated:


.. code-block:: python

from edc_reference.models import Reference

reference = Reference.objects.get(
identifier=self.subject_identifier,
timepoint=self.subject_visit.visit_code,
report_datetime=crf_one.report_datetime,
field_name='f1')

>>> reference.__dict__
{ ...
'datatype': 'CharField',
'field_name': 'f1',
'identifier': '1',
'model': 'edc_reference.crfone',
'report_datetime': datetime.datetime(2017, 7, 7, 13, 30, 6, 545140, tzinfo=<UTC>),
'timepoint': 'code',
'value_date': None,
'value_datetime': None,
'value_int': None,
'value_str': 'happiness',
...}


Get the ``value`` from the reference instance:

.. code-block:: python

>>> reference.value
'happiness'

Model managers methods are also available, for example:

.. code-block:: python

reference = Reference.objects.crf_get_for_visit(
model='edc_reference.crfone',
visit=self.subject_visit,
field_name='f1')

>>> reference.value
'happiness'


Accessing pivoted data with ``LongitudinalRefset``
===============================================

TODO



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