def apply(x):
if isinstance(x, dict):
inst.update(x)
elif is_collection(x):
for item in x:
apply(item)
elif isinstance(x, string_types):
inst.add_label(ustr(x))
else:
raise TypeError("Cannot cast %s to Node" % obj.__class__.__name__)
def _query_and_parameters(self, count=False):
""" A tuple of the Cypher query and parameters used to select
the relationships that match the criteria for this selection.
:return: Cypher query string
"""
def verify_node(n):
if n.graph != self.graph:
raise ValueError("Node %r does not belong to this graph" % n)
if n.identity is None:
raise ValueError("Node %r is not bound to a graph" % n)
def r_type_name(r):
try:
return r.__name__
except AttributeError:
return r
clauses = []
parameters = {}
if self._r_type is None:
relationship_detail = ""
elif is_collection(self._r_type):
relationship_detail = ":" + "|".join(
cypher_escape(r_type_name(t)) for t in self._r_type)
else:
relationship_detail = ":%s" % cypher_escape(
r_type_name(self._r_type))
if not self._nodes:
clauses.append("MATCH (a)-[_" + relationship_detail + "]->(b)")
elif isinstance(self._nodes, Sequence):
if len(self._nodes) >= 1 and self._nodes[0] is not None:
start_node = Node.cast(self._nodes[0])
verify_node(start_node)
clauses.append("MATCH (a) WHERE id(a) = $x")
parameters["x"] = start_node.identity
if len(self._nodes) >= 2 and self._nodes[1] is not None:
end_node = Node.cast(self._nodes[1])
verify_node(end_node)
clauses.append("MATCH (b) WHERE id(b) = $y")
parameters["y"] = end_node.identity
if len(self._nodes) >= 3:
raise ValueError("Node sequence cannot be longer than two")
clauses.append("MATCH (a)-[_" + relationship_detail + "]->(b)")
elif isinstance(self._nodes, Set):
nodes = {node for node in self._nodes if node is not None}
if len(nodes) >= 1:
start_node = Node.cast(nodes.pop())
verify_node(start_node)
clauses.append("MATCH (a) WHERE id(a) = $x")
parameters["x"] = start_node.identity
if len(nodes) >= 1:
end_node = Node.cast(nodes.pop())
verify_node(end_node)
clauses.append("MATCH (b) WHERE id(b) = $y")
parameters["y"] = end_node.identity
if len(nodes) >= 1:
raise ValueError("Node set cannot be larger than two")
clauses.append("MATCH (a)-[_" + relationship_detail + "]-(b)")
else:
raise ValueError("Nodes must be passed as a Sequence or a Set")
if self._predicates:
predicates = []
for predicate in self._predicates:
if isinstance(predicate, tuple):
predicate, param = predicate
parameters.update(param)
predicates.append(predicate)
clauses.append("WHERE %s" % " AND ".join(predicates))
if count:
clauses.append("RETURN count(_)")
else:
clauses.append("RETURN _")
if self._order_by:
clauses.append("ORDER BY %s" % (", ".join(self._order_by)))
if self._skip:
clauses.append("SKIP %d" % self._skip)
if self._limit is not None:
clauses.append("LIMIT %d" % self._limit)
return " ".join(clauses), parameters
