Class: Neo4j::Label

Inherits:
Object
  • Object
show all
Extended by:
Core::CypherTranslator
Defined in:
lib/neo4j/label.rb

Overview

A label is a named graph construct that is used to group nodes. See Neo4j::Node how to create and delete nodes

See Also:

Direct Known Subclasses

Embedded::EmbeddedLabel, Server::CypherLabel

Defined Under Namespace

Classes: InvalidQueryError

Constant Summary

Constants included from Core::CypherTranslator

Core::CypherTranslator::EMPTY_PROPS, Core::CypherTranslator::SANITIZE_ESCAPED_REGEXP

Class Method Summary collapse

Instance Method Summary collapse

Methods included from Core::CypherTranslator

create_escape_value, cypher_prop_list, cypher_string, escape_quotes, escape_value, label_string, prop_identifier, sanitize_escape_sequences, sanitized_column_names, translate_response

Class Method Details

.create(name, session = Neo4j::Session.current) ⇒ Object

Returns a label of given name that can be used to specifying constraints

Parameters:

  • name (Symbol, String) —

    the name of the label



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# File 'lib/neo4j/label.rb', line 67

def create(name, session = Neo4j::Session.current)
  session.create_label(name)
end

.find_all_nodes(label_name, session = Neo4j::Session.current) ⇒ Enumerable<Neo4j::Node>

Returns all nodes having given label. Nodes can be wrapped in your own model ruby classes.

Returns:

  • (Enumerable<Neo4j::Node>) —

    all nodes having given label. Nodes can be wrapped in your own model ruby classes.



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# File 'lib/neo4j/label.rb', line 73

def find_all_nodes(label_name, session = Neo4j::Session.current)
  session.find_all_nodes(label_name)
end

.find_nodes(label_name, key, value, session = Neo4j::Session.current) ⇒ Enumerable<Neo4j::Node>

Returns all nodes having given label and properties. Nodes can be wrapped in your own model ruby classes.

Returns:

  • (Enumerable<Neo4j::Node>) —

    all nodes having given label and properties. Nodes can be wrapped in your own model ruby classes.



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# File 'lib/neo4j/label.rb', line 78

def find_nodes(label_name, key, value, session = Neo4j::Session.current)
  session.find_nodes(label_name, key, value)
end

Instance Method Details

#create_constraint(property, constraints, session = Neo4j::Session.current) ⇒ Object

Creates a neo4j constraint on a property See docs.neo4j.org/chunked/stable/query-constraints.html

Examples:

label = Neo4j::Label.create(:person, session)
label.create_constraint(:name, {type: :unique}, session)


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# File 'lib/neo4j/label.rb', line 35

def create_constraint(property, constraints, session = Neo4j::Session.current)
  cypher = case constraints[:type]
           when :unique
             "CREATE CONSTRAINT ON (n:`#{name}`) ASSERT n.`#{property}` IS UNIQUE"
           else
             fail "Not supported constrain #{constraints.inspect} for property #{property} (expected :type => :unique)"
           end
  session._query_or_fail(cypher)
end

#create_index(*properties) ⇒ Object

This method is abstract. 


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# File 'lib/neo4j/label.rb', line 14

def create_index(*properties)
  fail 'not implemented'
end

#drop_constraint(property, constraint, session = Neo4j::Session.current) ⇒ Object

Drops a neo4j constraint on a property See docs.neo4j.org/chunked/stable/query-constraints.html

Examples:

label = Neo4j::Label.create(:person, session)
label.create_constraint(:name, {type: :unique}, session)
label.drop_constraint(:name, {type: :unique}, session)


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# File 'lib/neo4j/label.rb', line 52

def drop_constraint(property, constraint, session = Neo4j::Session.current)
  cypher = case constraint[:type]
           when :unique
             "DROP CONSTRAINT ON (n:`#{name}`) ASSERT n.`#{property}` IS UNIQUE"
           else
             fail "Not supported constrain #{constraint.inspect}"
           end
  session._query_or_fail(cypher)
end

#drop_index(*properties) ⇒ Object

This method is abstract. 


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# File 'lib/neo4j/label.rb', line 19

def drop_index(*properties)
  fail 'not implemented'
end

#indexes ⇒ Object

This method is abstract.

List indices for a label



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# File 'lib/neo4j/label.rb', line 25

def indexes
  fail 'not implemented'
end

#name ⇒ Object

This method is abstract. 


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# File 'lib/neo4j/label.rb', line 9

def name
  fail 'not implemented'
end