Add/improve easy querying functionality

[aiida-bot]

Originally reported by: Giovanni Pizzi (Bitbucket: pizzi, GitHub: giovannipizzi)

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Create wrapper functions (and maybe even a cmdline interface, partially already existing) to easily query attributes.

E.g., to query calculations done on a structure with a given element and at least num_elems_min, and containing a given string in the label:

#!python
def get_calcs(num_elems_min, element, label_string):
    from aiida.orm import DataFactory, Calculation
    from django.db.models import Count
    # Find attributes referring to the given element
    q1 = models.DbAttribute.objects.filter(key__startswith='sites.',key__endswith='.kind_name', tval=element)
    # Find structures with those attributes
    q2 = DataFactory('structure').query(dbattributes__in=q1)
    # Annotate the number of attributes (of the specified type) 
    q3 = q2.annotate(num_elems=Count('dbattributes'))
    # filter only those with at least the specified # of elements
    q4 = q3.filter(num_elems__gte=num_elems_min)
    # Query calculations using as input the specified structures
    q5 = Calculation.query(label__contains=label_string, inputs__in=q4)
    # return a Django QuerySet with the resulting calculations
    return q5.distinct()

print "I found %s entries." % get_calcs(num_elems_min=2, element='Fe', label_string='MD').count()

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• Bitbucket: https://bitbucket.org/aiida_team/aiida_core/issue/104

[aiida-bot]

Original comment by Giovanni Pizzi (Bitbucket: pizzi, GitHub: giovannipizzi):

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Committed first version of querytool in 57abb61
Example of usage:

#!python
#!/usr/bin/env runaiida

from aiida.orm.querytool import QueryTool

Ph = CalculationFactory('quantumespresso.ph')
Pw = CalculationFactory('quantumespresso.pw')
ParameterData = DataFactory('parameter')
q = QueryTool()
q.set_class(Ph)
q.add_attr_filter('state', '=', 'FINISHED')
q.add_attr_filter('INPUTPH.nq1', '>=', 4, relnode='inp.parameters')

print [_.pk for _ in q.run_query()]

q = QueryTool()
q.set_class(ParameterData)
q.add_attr_filter('INPUTPH.nq1', '>=', 4)
q.add_attr_filter('state', '=', 'FINISHED', relnode='out.parameters', relnodeclass=Ph)

print [_.pk for _ in q.run_query()]

Still to do:

• document it
• add to the todo what is missing/should be implemented (it's in the docstrings of the QueryTool class)
• add the QueryTool to the things automatically imported by verdi run/shell

[aiida-bot]

Original comment by Giovanni Pizzi (Bitbucket: pizzi, GitHub: giovannipizzi):

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Duplicate of #178.

[aiida-bot]

Original comment by Giovanni Pizzi (Bitbucket: pizzi, GitHub: giovannipizzi):

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This is now addressed with the QueryBuilder. The QueryTool will be deprecated.