Created
May 7, 2012 15:24
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QuerySet relational filtering workaround (as of 5/7/2012. neo4django 03b247d7911753)
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# a hack for `NodeA.objects.filter(nodeb__in=nodebnodes)` | |
from neo4django.db import connections | |
from neo4django.db.models.script_utils import LazyNode | |
# ... | |
b_nodes = set([...]) #your NodeB instances | |
b_node_ids = [b.id for b in b_nodes] | |
type_node_a = NodeA._type_node() | |
cypher_query = 'START b=node({b_ids}), t=node({type_node_id}) MATCH b -[r]-> a, t -[`<<INSTANCE>>`]->a RETURN a' | |
table = connections['default'].cypher(cypher_query, b_ids = b_node_ids, type_node_id = type_node_a.id) | |
models = [NodeA._neo4j_instance(LazyNode.from_dict(r[0])) for r in table['data']] |
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Big thanks for this example and the issue comment. Although the ORM layer is great for supporting other Django extensions that assume RDBMS, I would have to agree that Cypher query is a huge plus.
Little question: I've reviewed a few other neo4j extensions, both in the Rails and Python, and for most I've seen them simply put a property in the node that represents the class (ie element_type = 'Person') as opposed to the direction that neo4django takes, which is a class type reference node (ie model_name='Person' - [:<>] -> nodes). I have never been able to find a document that explains the pros and cons of both methods or Lucene comparison against the other. I also assumed that the way neo4django does it was the old way, before built integrated search engines were available such as Neo4j and Lucene. Do you mind sharing your views?