问题
I don't know how to create a method to delete edges in django rest framework, using orientdb OGM.
I'm using pyorient==1.5.5 and OrientDB 3.0.18 version.
I have two vertex Classes: ousers, ocompany. Also I have two relationships (edges) Classes: ofriends, oworksat. So for example:
To make a ofriends relationship I need two ousers. And to make a oworksat relationship I need one ouser and one ocompany. Every relationship has it own cluster id.
I know that I can access to these functions:
(Pdb) dir(graph)
['PROPERTY_TYPES', '_GROOVY_GET_DB', '_GROOVY_NULL_LISTENER', '_GROOVY_TRY', 'class', 'delattr', 'dict', 'dir', 'doc', 'eq', 'format', 'ge', 'getattribute', 'gt', 'hash', 'init', 'le', 'lt', 'module', 'ne', 'new', 'reduce', 'reduce_ex', 'repr', 'setattr', 'sizeof', 'str', 'subclasshook', 'weakref', '_last_cred', '_last_db', '_last_user', 'batch', 'both', 'bothE', 'build_mapping', 'clear_registry', 'client', 'coerce_class_names', 'coerce_class_names_to_quoted', 'compute_all_properties', 'config', 'create_all', 'create_class', 'create_edge', 'create_edge_command', 'create_function', 'create_props_mapping', 'create_vertex', 'create_vertex_command', 'delete_vertex', 'delete_vertex_command', 'drop', 'drop_all', 'drop_class', 'edge_from_record', 'edges_from_records', 'element_from_link', 'element_from_record', 'elements_from_links', 'elements_from_records', 'export', 'get_edge', 'get_element', 'get_vertex', 'gremlin', 'guard_reserved_words', 'inE', 'in_', 'include', 'init_broker_for_class', 'list_superclasses', 'ocompany', 'ofriends', 'open', 'ousers', 'out', 'outE', 'oworksat', 'populate', 'property_from_schema', 'props_from_db', 'props_to_db', 'query', 'registry', 'save_element', 'scripts', 'server_version', 'strict', 'toposort_classes', 'valid_element_base', 'vertex_from_record', 'vertexes_from_records']
If I do:
graph.delete_vertex("#21:0")
It works good and deletes #21:0 ouser vertex row, which is part of ofriends and oworskat relationships, so also, that command deletes the relationship where that vertex is included. Obviously, I don't want to delete the entire vertex, just only the specific edge (not the class, just the relationship row).
I was wondering if exists some command like delete_edge(), but dir(graph) don't tell me nothing related.
settings.py
from pyorient.ogm import Graph, Config
from pyorient.serializations import OrientSerialization
from pyorient.ogm import declarative
BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
config = RawConfigParser()
config.read(BASE_DIR + '/settings.ini')
ORIENTDB = {
'NAME': config.get('orientdbConf', 'DB_NAME'),
'USER': config.get('orientdbConf', 'DB_USER'),
'PASSWORD': config.get('orientdbConf', 'DB_PASS'),
'HOST': config.get('orientdbConf', 'DB_HOST'),
'PORT': config.get('orientdbConf', 'DB_PORT'),
}
Config.from_url('plocal://'+ORIENTDB['HOST']+':'+str(ORIENTDB['PORT'])+'/'+ORIENTDB['NAME']+'',''+ORIENTDB['USER']+'', ''+ORIENTDB['PASSWORD']+'',initial_drop=False,serialization_type=OrientSerialization.Binary)
graph = Graph(Config.from_url(''+ORIENTDB['HOST']+'/'+ORIENTDB['NAME']+'',''+ORIENTDB['USER']+'', ''+ORIENTDB['PASSWORD']+'',initial_drop=False))
Node = declarative.declarative_node()
Relationship = declarative.declarative_relationship()
models.py
from core.settings import Node,Relationship,graph
from pyorient.ogm.property import (String, Date, DateTime, Decimal, Double,
Integer, Boolean, EmbeddedMap, EmbeddedSet,Link, UUID)
class OUsers(Node):
element_plural = 'ousers'
postgresql_id=Integer(nullable=False,unique=True)
class OCompany(Node):
element_plural = 'ocompany'
postgresql_id=Integer(nullable=False,unique=True)
class OFriends(Relationship):
label = 'ofriends'
from_postgresql_ouser_id=Integer(nullable=False,unique=True)
to_postgresql_ouser_id=Integer(nullable=False,unique=True)
class OWorksAt(Relationship):
label = 'oworksat'
from_postgresql_ouser_id=Integer(nullable=False,unique=True)
to_postgresql_ocompany_id=Integer(nullable=False,unique=True)
graph.create_all(Node.registry)
graph.create_all(Relationship.registry)
serializers.py
from .models import (OUsers,OCompany,OFriends,OWorksAt)
from rest_framework import serializers
from django.contrib.auth import get_user_model
User = get_user_model()
class OFriendsSerializer(serializers.Serializer):
from_postgresql_ouser_id = serializers.IntegerField()
to_postgresql_ouser_id = serializers.IntegerField()
def create(self, data):
return OFriends.objects.create(**data)
def update(self, instance, data):
instance.from_postgresql_ouser_id = data.get("from_postgresql_ouser_id")
instance.to_postgresql_ouser_id = data.get("to_postgresql_ouser_id")
instance.save()
return instance
class OFriendsSerializer(serializers.Serializer):
from_postgresql_ouser_id = serializers.IntegerField()
to_postgresql_ouser_id = serializers.IntegerField()
def create(self, data):
return OFriends.objects.create(**data)
def update(self, instance, data):
instance.from_postgresql_ouser_id = data.get("from_postgresql_ouser_id")
instance.to_postgresql_ouser_id = data.get("to_postgresql_ouser_id")
instance.save()
return instance
api.py
class OFriendsViewSet(viewsets.ModelViewSet):
def destroy(self, request, *args, **kwargs):
queryset = graph.ofriends.query()
import pdb;pdb.set_trace()
# HERE should be the command
回答1:
According with the pyorient OGM documentation, that functionality was never added. I already created an issue in the repository.
So at the moment, I solved my problem using pyorient client, with raw query:
pyorient_client.py
from core.settings import ORIENTDB
import pyorient
def orientdbConnection():
"""Orientdb client connection"""
client = None
try:
client = pyorient.OrientDB(ORIENTDB['HOST'], int(ORIENTDB['PORT']))
session_id = client.connect( ORIENTDB['USER'], ORIENTDB['PASSWORD'] )
if client.db_exists( ORIENTDB['NAME'], pyorient.STORAGE_TYPE_MEMORY ):
client.db_open( ORIENTDB['NAME'], ORIENTDB['USER'], ORIENTDB['PASSWORD'])
except Exception as e:
print ("[ ERROR ] Fail orientdb connection. Error: " + str(e))
return client
And in the api.py
from rest_framework import status
from rest_framework.response import Response
from core.pyorient_client import *
class OFriendsViewSet(viewsets.ModelViewSet):
def destroy(self, request, *args, **kwargs):
client = orientdbConnection()
client.command("delete edge ofriends where @rid = '" + kwargs['pk'] + "'")
return Response(status=status.HTTP_204_NO_CONTENT)
Maybe this could be useful for anyone else. Note that I receive o'friends @rid as a parameter (by passing the id in DELETE method in swagger UI).
来源：https://stackoverflow.com/questions/56517510/what-is-the-correctly-way-to-delete-edges-with-orientdb-ogm-in-django-rest-frame