class DeleteStatement(object):
""" Builder for a Cypher DELETE statement.
"""
#: The graph against which this statement is to be executed.
graph = None
#: The parameters to inject into this statement.
parameters = None
def __init__(self, graph):
self.graph = graph
self.supports_node_labels = self.graph.supports_node_labels
self.entities = []
self.start_or_match_clause = StartOrMatch(self.graph)
self.delete_rels_clause = []
self.delete_nodes_clause = []
self.parameters = {}
def __repr__(self):
return self.string
def __str__(self):
return xstr(self.__unicode__())
def __unicode__(self):
return self.string
def __contains__(self, entity):
return any(e is entity for e in self.entities)
@property
def string(self):
""" The full Cypher statement as a string.
"""
clauses = []
if self.start_or_match_clause:
clauses.append(self.start_or_match_clause.string.rstrip())
if self.delete_rels_clause:
clauses.append("DELETE " + ",".join(self.delete_rels_clause))
if self.delete_nodes_clause:
clauses.append("DELETE " + ",".join(self.delete_nodes_clause))
return "\n".join(clauses)
def post(self):
return self.graph.cypher.post(self.string, self.parameters)
def execute(self):
""" Execute this statement.
"""
if self.string:
self.post().close()
def delete(self, entity):
""" Append an entity to the DELETE clause of this statement.
:arg entity: The entity to delete.
"""
entity = Graph.cast(entity)
index = len(self.entities)
name = _(index)
if isinstance(entity, Node):
self._delete_node(entity, name)
elif isinstance(entity, Relationship):
self._delete_relationship(entity, name)
elif isinstance(entity, Path):
self._delete_path(entity, name)
self.entities.append(entity)
def _delete_node(self, node, name):
if node.bound:
self.start_or_match_clause.node(name, "{%s}" % name)
self.delete_nodes_clause.append(name)
self.parameters[name] = node._id
def _delete_relationship(self, relationship, name):
if relationship.bound:
self.start_or_match_clause.relationship(name, "{%s}" % name)
self.delete_rels_clause.append(name)
self.parameters[name] = relationship._id
def _delete_path(self, path, name):
for i, rel in enumerate(path.relationships):
self._delete_relationship(rel, name + "r" + ustr(i))
for i, node in enumerate(path.nodes):
self._delete_node(node, name + "n" + ustr(i))
class CreateStatement(object):
""" Builder for a Cypher CREATE/CREATE UNIQUE statement.
"""
#: The graph against which this statement is to be executed.
graph = None
#: The parameters to inject into this statement.
parameters = None
def __init__(self, graph):
self.graph = graph
self.supports_node_labels = self.graph.supports_node_labels
self.entities = []
self.names = []
self.start_or_match_clause = StartOrMatch(self.graph)
self.create_clause = []
self.create_unique_clause = []
self.return_clause = []
self.parameters = {}
def __repr__(self):
return self.string
def __str__(self):
return xstr(self.__unicode__())
def __unicode__(self):
return self.string
def __contains__(self, entity):
return any(e is entity for e in self.entities)
@property
def string(self):
""" The full Cypher statement as a string.
"""
clauses = [self.start_or_match_clause.string]
if self.create_clause:
clauses.append("CREATE " + ",".join(self.create_clause))
if self.create_unique_clause:
clauses.append("CREATE UNIQUE " +
",".join(self.create_unique_clause))
if self.return_clause:
clauses.append("RETURN " + ",".join(self.return_clause))
return "\n".join(clauses).strip()
def post(self):
return self.graph.cypher.post(self.string, self.parameters)
def execute(self):
""" Execute this statement.
:return: A tuple of created entities.
"""
if not self.entities:
return ()
raw = self.post().content
columns = raw["columns"]
data = raw["data"]
dehydrated = dict(zip(columns, data[0]))
for i, entity in enumerate(self.entities):
node_names, rel_names = self.names[i]
if isinstance(entity, Node):
metadata = dehydrated[node_names[0]]
entity.bind(metadata["self"], metadata)
elif isinstance(entity, Relationship):
metadata = dehydrated[rel_names[0]]
entity.bind(metadata["self"], metadata)
elif isinstance(entity, Path):
for j, node in enumerate(entity.nodes):
metadata = dehydrated[node_names[j]]
node.bind(metadata["self"], metadata)
for j, rel in enumerate(entity.rels):
metadata = dehydrated[rel_names[j]]
rel.bind(metadata["self"], metadata)
return tuple(self.entities)
def create(self, entity):
""" Append an entity to the CREATE clause of this statement.
:arg entity: The entity to create.
"""
entity = Graph.cast(entity)
index = len(self.entities)
name = _(index)
if isinstance(entity, Node):
self.names.append(self._create_node(entity, name))
elif isinstance(entity, Path):
self.names.append(self._create_path(entity, name, unique=False))
else:
raise TypeError("Cannot create entity of type %s" %
type(entity).__name__)
self.entities.append(entity)
def create_unique(self, entity):
""" Append an entity to the CREATE UNIQUE clause of this statement.
:arg entity: The entity to add.
"""
entity = Graph.cast(entity)
index = len(self.entities)
name = _(index)
if isinstance(entity, Path):
if len(entity) == 0:
raise ValueError("Cannot create unique path with zero length")
if not any(node.bound or node in self for node in entity.nodes):
raise ValueError(
"At least one node must be bound to create a unique path")
self.names.append(self._create_path(entity, name, unique=True))
else:
raise TypeError("Cannot create unique entity of type %s" %
type(entity).__name__)
self.entities.append(entity)
def _node_pattern(self, node, name, full):
template = "{name}"
kwargs = {"name": name}
if full:
if node.labels and self.supports_node_labels:
template += "{labels}"
kwargs["labels"] = "".join(":" + cypher_escape(label)
for label in node.labels)
if node.properties:
template += " {{{name}}}"
self.parameters[name] = node.properties
return "(" + template.format(**kwargs) + ")"
def _create_node(self, node, name):
if node.bound:
self.start_or_match_clause.node(name, "{" + name + "}")
self.parameters[name] = node._id
else:
self.create_clause.append(self._node_pattern(node, name,
full=True))
self.return_clause.append(name)
return [name], []
def _create_path_nodes(self, path, name, unique):
node_names = []
for i, node in enumerate(path.nodes):
if isinstance(node, NodePointer):
node_names.append(_(node.address))
# Switch out node with object from elsewhere in entity list
nodes = list(path.nodes)
try:
target_node = self.entities[node.address]
except IndexError:
raise IndexError("Node pointer {%s} out of range" %
node.address)
if not isinstance(target_node, Node):
raise ValueError("Pointer {%s} does not refer to a node" %
node.address)
nodes[i] = target_node
path._Path__nodes = tuple(nodes)
elif node in self:
node_name = _(self.entities.index(node))
node_names.append(node_name)
elif unique and not node.bound:
node_name = name + "n" + ustr(i)
node_names.append(node_name)
self.return_clause.append(node_name)
else:
node_name = name + "n" + ustr(i)
node_names.append(node_name)
self._create_node(node, node_name)
return node_names
def _create_path(self, path, name, unique):
node_names = self._create_path_nodes(path, name, unique)
rel_names = []
for i, rel in enumerate(path.rels):
rel_name = name + "r" + ustr(i)
rel_names.append(rel_name)
if rel.bound:
self.start_or_match_clause.relationship(
rel_name, "{" + rel_name + "}")
self.parameters[rel_name] = rel._id
else:
if rel.properties:
template = "{start}-[{name}:{type} {{{name}}}]->{end}"
self.parameters[rel_name] = rel.properties
else:
template = "{start}-[{name}:{type}]->{end}"
start_index, end_index = i, i + 1
if isinstance(rel, Rev):
start_index, end_index = end_index, start_index
start_node = path.nodes[start_index]
end_node = path.nodes[end_index]
start = self._node_pattern(start_node,
node_names[start_index],
full=(unique
and not start_node.bound
and start_node not in self))
end = self._node_pattern(end_node,
node_names[end_index],
full=(unique and not end_node.bound
and end_node not in self))
kwargs = {
"start": start,
"name": rel_name,
"type": cypher_escape(rel.type),
"end": end
}
if unique:
self.create_unique_clause.append(template.format(**kwargs))
else:
self.create_clause.append(template.format(**kwargs))
self.return_clause.append(rel_name)
return node_names, rel_names
class CreateStatement(object):
""" Builder for a Cypher CREATE/CREATE UNIQUE statement.
"""
#: The graph against which this statement is to be executed.
graph = None
#: The parameters to inject into this statement.
parameters = None
def __init__(self, graph):
self.graph = graph
self.supports_node_labels = self.graph.supports_node_labels
self.entities = []
self.names = []
self.start_or_match_clause = StartOrMatch(self.graph)
self.create_clause = []
self.create_unique_clause = []
self.return_clause = []
self.parameters = {}
def __repr__(self):
return self.string
def __str__(self):
return xstr(self.__unicode__())
def __unicode__(self):
return self.string
def __contains__(self, entity):
return any(e is entity for e in self.entities)
@property
def string(self):
""" The full Cypher statement as a string.
"""
clauses = [self.start_or_match_clause.string]
if self.create_clause:
clauses.append("CREATE " + ",".join(self.create_clause))
if self.create_unique_clause:
clauses.append("CREATE UNIQUE " + ",".join(self.create_unique_clause))
if self.return_clause:
clauses.append("RETURN " + ",".join(self.return_clause))
return "\n".join(clauses).strip()
def post(self):
return self.graph.cypher.post(self.string, self.parameters)
def execute(self):
""" Execute this statement.
:return: A tuple of created entities.
"""
if not self.entities:
return ()
raw = self.post().content
columns = raw["columns"]
data = raw["data"]
dehydrated = dict(zip(columns, data[0]))
for i, entity in enumerate(self.entities):
node_names, rel_names = self.names[i]
if isinstance(entity, Node):
metadata = dehydrated[node_names[0]]
entity.bind(metadata["self"], metadata)
elif isinstance(entity, Relationship):
metadata = dehydrated[rel_names[0]]
entity.bind(metadata["self"], metadata)
elif isinstance(entity, Path):
for j, node in enumerate(entity.nodes):
metadata = dehydrated[node_names[j]]
node.bind(metadata["self"], metadata)
for j, rel in enumerate(entity.rels):
metadata = dehydrated[rel_names[j]]
rel.bind(metadata["self"], metadata)
return tuple(self.entities)
def create(self, entity):
""" Append an entity to the CREATE clause of this statement.
:arg entity: The entity to create.
"""
entity = Graph.cast(entity)
index = len(self.entities)
name = _(index)
if isinstance(entity, Node):
self.names.append(self._create_node(entity, name))
elif isinstance(entity, Path):
self.names.append(self._create_path(entity, name, unique=False))
else:
raise TypeError("Cannot create entity of type %s" % type(entity).__name__)
self.entities.append(entity)
def create_unique(self, entity):
""" Append an entity to the CREATE UNIQUE clause of this statement.
:arg entity: The entity to add.
"""
entity = Graph.cast(entity)
index = len(self.entities)
name = _(index)
if isinstance(entity, Path):
if len(entity) == 0:
raise ValueError("Cannot create unique path with zero length")
if not any(node.bound or node in self for node in entity.nodes):
raise ValueError("At least one node must be bound to create a unique path")
self.names.append(self._create_path(entity, name, unique=True))
else:
raise TypeError("Cannot create unique entity of type %s" % type(entity).__name__)
self.entities.append(entity)
def _node_pattern(self, node, name, full):
template = "{name}"
kwargs = {"name": name}
if full:
if node.labels and self.supports_node_labels:
template += "{labels}"
kwargs["labels"] = "".join(":" + cypher_escape(label) for label in node.labels)
if node.properties:
template += " {{{name}}}"
self.parameters[name] = node.properties
return "(" + template.format(**kwargs) + ")"
def _create_node(self, node, name):
if node.bound:
self.start_or_match_clause.node(name, "{" + name + "}")
self.parameters[name] = node._id
else:
self.create_clause.append(self._node_pattern(node, name, full=True))
self.return_clause.append(name)
return [name], []
def _create_path_nodes(self, path, name, unique):
node_names = []
for i, node in enumerate(path.nodes):
if isinstance(node, NodePointer):
node_names.append(_(node.address))
# Switch out node with object from elsewhere in entity list
nodes = list(path.nodes)
try:
target_node = self.entities[node.address]
except IndexError:
raise IndexError("Node pointer {%s} out of range" % node.address)
if not isinstance(target_node, Node):
raise ValueError("Pointer {%s} does not refer to a node" % node.address)
nodes[i] = target_node
path._Path__nodes = tuple(nodes)
elif node in self:
node_name = _(self.entities.index(node))
node_names.append(node_name)
elif unique and not node.bound:
node_name = name + "n" + ustr(i)
node_names.append(node_name)
self.return_clause.append(node_name)
else:
node_name = name + "n" + ustr(i)
node_names.append(node_name)
self._create_node(node, node_name)
return node_names
def _create_path(self, path, name, unique):
node_names = self._create_path_nodes(path, name, unique)
rel_names = []
for i, rel in enumerate(path.rels):
rel_name = name + "r" + ustr(i)
rel_names.append(rel_name)
if rel.bound:
self.start_or_match_clause.relationship(rel_name, "{" + rel_name + "}")
self.parameters[rel_name] = rel._id
else:
if rel.properties:
template = "{start}-[{name}:{type} {{{name}}}]->{end}"
self.parameters[rel_name] = rel.properties
else:
template = "{start}-[{name}:{type}]->{end}"
start_index, end_index = i, i + 1
if isinstance(rel, Rev):
start_index, end_index = end_index, start_index
start_node = path.nodes[start_index]
end_node = path.nodes[end_index]
start = self._node_pattern(start_node, node_names[start_index],
full=(unique and not start_node.bound and start_node not in self))
end = self._node_pattern(end_node, node_names[end_index],
full=(unique and not end_node.bound and end_node not in self))
kwargs = {"start": start, "name": rel_name,
"type": cypher_escape(rel.type), "end": end}
if unique:
self.create_unique_clause.append(template.format(**kwargs))
else:
self.create_clause.append(template.format(**kwargs))
self.return_clause.append(rel_name)
return node_names, rel_names
class DeleteStatement(object):
""" Builder for a Cypher DELETE statement.
"""
#: The graph against which this statement is to be executed.
graph = None
#: The parameters to inject into this statement.
parameters = None
def __init__(self, graph):
self.graph = graph
self.supports_node_labels = self.graph.supports_node_labels
self.entities = []
self.start_or_match_clause = StartOrMatch(self.graph)
self.delete_rels_clause = []
self.delete_nodes_clause = []
self.parameters = {}
def __repr__(self):
return self.string
def __str__(self):
return xstr(self.__unicode__())
def __unicode__(self):
return self.string
def __contains__(self, entity):
return any(e is entity for e in self.entities)
@property
def string(self):
""" The full Cypher statement as a string.
"""
clauses = []
if self.start_or_match_clause:
clauses.append(self.start_or_match_clause.string.rstrip())
if self.delete_rels_clause:
clauses.append("DELETE " + ",".join(self.delete_rels_clause))
if self.delete_nodes_clause:
clauses.append("DELETE " + ",".join(self.delete_nodes_clause))
return "\n".join(clauses)
def post(self):
return self.graph.cypher.post(self.string, self.parameters)
def execute(self):
""" Execute this statement.
"""
if self.string:
self.post().close()
def delete(self, entity):
""" Append an entity to the DELETE clause of this statement.
:arg entity: The entity to delete.
"""
entity = Graph.cast(entity)
index = len(self.entities)
name = _(index)
if isinstance(entity, Node):
self._delete_node(entity, name)
elif isinstance(entity, Relationship):
self._delete_relationship(entity, name)
elif isinstance(entity, Path):
self._delete_path(entity, name)
self.entities.append(entity)
def _delete_node(self, node, name):
if node.bound:
self.start_or_match_clause.node(name, "{%s}" % name)
self.delete_nodes_clause.append(name)
self.parameters[name] = node._id
def _delete_relationship(self, relationship, name):
if relationship.bound:
self.start_or_match_clause.relationship(name, "{%s}" % name)
self.delete_rels_clause.append(name)
self.parameters[name] = relationship._id
def _delete_path(self, path, name):
for i, rel in enumerate(path.relationships):
self._delete_relationship(rel, name + "r" + ustr(i))
for i, node in enumerate(path.nodes):
self._delete_node(node, name + "n" + ustr(i))