Property Definitions

Overview

Define ontology properties to describe relationships between classes (object properties) and attributes of nodes (data properties).

Object Properties

Object properties define edge types with domain (source) and range (target) constraints:

GQL
// Person knows Person
CREATE OBJECT PROPERTY @foaf:knows DOMAIN @foaf:Person RANGE @foaf:Person

GQL
// Person works for Organization
CREATE OBJECT PROPERTY @ex:worksFor DOMAIN @ex:Person RANGE @ex:Organization

GQL
// Organization employs Person
CREATE OBJECT PROPERTY @ex:employs DOMAIN @ex:Organization RANGE @ex:Person

Property Characteristics

Properties can have special characteristics that affect behavior:

Create property with characteristics:

GQL
// knows is symmetric - if Alice knows Bob, Bob knows Alice
CREATE OBJECT PROPERTY @foaf:knows DOMAIN @foaf:Person RANGE @foaf:Person SYMMETRIC

GQL
// ancestorOf is transitive - if A ancestor of B, B ancestor of C, then A ancestor of C
CREATE OBJECT PROPERTY @ex:ancestorOf DOMAIN @ex:Person RANGE @ex:Person TRANSITIVE

GQL
// hasBirthPlace is functional - a person has only one birthplace
CREATE OBJECT PROPERTY @ex:hasBirthPlace DOMAIN @ex:Person RANGE @ex:Location FUNCTIONAL

Inverse Properties

Define inverse relationships:

GQL
// worksFor and employs are inverses
CREATE OBJECT PROPERTY @ex:worksFor DOMAIN @ex:Person RANGE @ex:Organization
CREATE OBJECT PROPERTY @ex:employs DOMAIN @ex:Organization RANGE @ex:Person INVERSE OF @ex:worksFor

When you create one edge, the inverse is automatically inferred:

GQL
// Insert worksFor edge
INSERT (:@ex:Person {name: 'Alice'})-[:@ex:worksFor]->(:@ex:Organization {name: 'Acme'})

// Query employs (inverse) - returns the same relationship
MATCH (org@ex:Organization)-[:@ex:employs]->(person@ex:Person)
RETURN org.name, person.name

Cardinality Constraints

Limit the number of relationships:

GQL
// A person can have at most one spouse
CREATE OBJECT PROPERTY @ex:hasSpouse FUNCTIONAL

GQL
// A country has exactly one capital
CREATE OBJECT PROPERTY @ex:hasCapital
  DOMAIN @ex:Country
  RANGE @ex:City
  FUNCTIONAL

Data Properties

Data properties define attributes with XSD types:

GQL
// String property
CREATE DATA PROPERTY @foaf:name DOMAIN @foaf:Agent TYPE xsd:string

GQL
// Numeric properties
CREATE DATA PROPERTY @foaf:age DOMAIN @foaf:Person TYPE xsd:integer
CREATE DATA PROPERTY @ex:salary DOMAIN @ex:Employee TYPE xsd:decimal

GQL
// Date/time properties
CREATE DATA PROPERTY @ex:birthDate DOMAIN @ex:Person TYPE xsd:date
CREATE DATA PROPERTY @ex:createdAt DOMAIN @ex:Document TYPE xsd:dateTime

GQL
// Boolean property
CREATE DATA PROPERTY @ex:isActive DOMAIN @ex:Account TYPE xsd:boolean

Supported XSD types:

Viewing Properties

List all defined properties:

GQL
SHOW PROPERTIES

Deleting Properties

Remove a property definition:

GQL
DROP PROPERTY @ex:tempProperty

Remove if exists:

GQL
DROP PROPERTY IF EXISTS @ex:tempProperty