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Data stored in a graph instead of a table:

Nodes (vertices) and Relationships (edges)
Relationships are directed and have a “type”, Nodes can have labels
Dynamically-typed Properties on both Nodes and Relationships

:Person

:knows

since: 2012

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Traditional table-based model (SQL / NoSQL)

Id	Name	Born
1	‘Bob’	1978
2	‘Alice’	1980

Id	PersonId	OtherId	Since
1	1	2	2012

Person

Knows

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Cypher query language:

match (bob:Person {name: ‘Bob’})-[:knows]->(alice:Person {name: ‘Alice’})

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Cypher query language:

match (bob:Person {name: ‘Bob’})-[:knows]->(alice:Person {name: ‘Alice’})

with bob, alice

match (bob)-[:knows*1..6]->(other:Person)-[rel:knows]->(alice)

where rel.since > 2000

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Dynamic definition with no formal schema (limited indexing and constraints):

Very easy to prototype, modify and extend - no need for schema migrations!

:Person

:knows

since: 2012

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Dynamic definition with no formal schema (limited indexing and constraints):

Very easy to prototype, modify and extend - no need for schema migrations!

:Person

:knows

since: 2012

>>> from py2neo import Node, Relationship�>>> a = Node("Person", name="Alice")�>>> b = Node("Person", name="Bob")�>>> ab = Relationship(a, "knows", b)�>>> ab�(alice)-[:knows]->(bob)

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Dynamic definition with no formal schema (limited indexing and constraints):

Very easy to prototype, modify and extend - no need for schema migrations!
No validation! Very easy to have typos and other undetected mistakes!

:Person

:knows

since: 2012

>>> from py2neo import Node, Relationship�>>> a = Node("Person", name="Alice")�>>> b = Node("Person", name="Bob")�>>> ab = Relationship(a, "knows", b)�>>> ab�(alice)-[:knows]->(bob)

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Dynamic definition with no formal schema (limited indexing and constraints):

Very easy to prototype, modify and extend - no need for schema migrations!
No validation! Very easy to have typos and other undetected mistakes!
Difficult to manage a large body of code without more formal abstractions

:Person

:knows

since: 2012

>>> from py2neo import Node, Relationship�>>> a = Node("Person", name="Alice")�>>> b = Node("Person", name="Bob")�>>> ab = Relationship(a, "knows", b)�>>> ab�(alice)-[:knows]->(bob)

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A social platform to create and share rich learning activities:

Developed in Montréal in 2013
Mainly used for Primary, Secondary and CÉGEP content
Also professional training and adult education

Backend technology stack:

Python 2.7 backend with Neo4j as main database
MySQL and Redis where appropriate

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A social platform to create and share rich learning activities:

7k teachers
150k students
600+ schools
270k users total

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A social platform to create and share rich learning activities:

7k teachers
150k students
600+ schools
270k users total

45 million Nodes
76 million Relationships
326 million Properties
2k requests/min

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neolixir

An Object-Relational Mapping (ORM) abstraction for Neo4j:

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neolixir

An Object-Relational Mapping (ORM) abstraction for Neo4j:

Declarative model definition

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Declarative model definition

In [1]: from neolixir import *

In [2]: class Person(Node):

...: name = String()

...: born = Integer()

...: knows = RelOut('knows')

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Declarative model definition

In [1]: from neolixir import *

In [2]: class Person(Node):

...: name = String()

...: born = Integer()

...: knows = RelOut('knows')

In [3]: bob = Person(name='Bob', born=1978)

In [4]: bob

Out[4]:

<Person (0x31073d0):

Id = None

Descriptors = ['born', 'knows', 'name']

Properties = {'born': 1978, 'name': u'Bob'}

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neolixir

An Object-Relational Mapping (ORM) abstraction for Neo4j:

Declarative model definition
Polymorphic inheritance

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Polymorphic inheritance

In [2]: class Person(Node):

...: name = String()

...: born = Integer()

...: knows = RelOut('knows')

In [5]: class Student(Person):

...: grade = Integer()

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Polymorphic inheritance

In [2]: class Person(Node):

...: name = String()

...: born = Integer()

...: knows = RelOut('knows')

In [5]: class Student(Person):

...: grade = Integer()

In [6]: alice = Student(name='Alice', born=1980, grade=8)

In [7]: alice

Out[7]:

<Student (0x33eb890):

Id = None

Descriptors = ['born', 'grade', 'knows', 'name']

Properties = {'grade': 8, 'born': 1980, 'name': u'Alice'}

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neolixir

An Object-Relational Mapping (ORM) abstraction for Neo4j:

Declarative model definition
Polymorphic inheritance
Relationship abstraction

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Relationship abstraction

In [3]: class Person(Node):

...: name = String()

...: knows = RelOut('knows')

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Relationship abstraction

In [2]: class KnowsRel(Relationship):

...: __rel_type__ = 'knows'

...: since = DateTime()

In [3]: class Person(Node):

...: name = String()

...: knows = RelOut(KnowsRel)

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Relationship abstraction

In [2]: class KnowsRel(Relationship):

...: __rel_type__ = 'knows'

...: since = DateTime()

In [3]: class Person(Node):

...: name = String()

...: knows = RelOut(KnowsRel)

In [4]: bob = Person(name='Bob')

In [5]: alice = Person(name='Alice')

In [6]: bob.knows.append(alice)

Out[6]: <KnowsRel (0x27e7810): (None)-[None:knows]->(None) {}>

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Relationship abstraction

In [2]: class KnowsRel(Relationship):

...: __rel_type__ = 'knows'

...: since = DateTime()

In [3]: class Person(Node):

...: name = String()

...: knows = RelOut(KnowsRel)

In [4]: bob = Person(name='Bob')

In [5]: alice = Person(name='Alice')

In [6]: bob.knows.append(alice)

Out[6]: <KnowsRel (0x27e7810): (None)-[None:knows]->(None) {}>

In [7]: alice in bob.knows

Out[7]: True

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Relationship abstraction

In [7]: bob.knows

Out[7]:

[<Person (0x27a9350):

Id = None

Descriptors = ['knows', 'name']

Properties = {'name': u'Alice'}

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Relationship abstraction

In [7]: bob.knows

Out[7]:

[<Person (0x27a9350):

Id = None

Descriptors = ['knows', 'name']

Properties = {'name': u'Alice'}

In [8]: bob.knows.rels()

Out[8]: [<KnowsRel (0x27e7810): (None)-[None:knows]->(None) {}>]

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Relationship abstraction

In [7]: bob.knows

Out[7]:

[<Person (0x27a9350):

Id = None

Descriptors = ['knows', 'name']

Properties = {'name': u'Alice'}

In [8]: bob.knows.rels()

Out[8]: [<KnowsRel (0x27e7810): (None)-[None:knows]->(None) {}>]

In [9]: bob.knows.rel(alice).since = '2012-01-01'

In [10]: bob.knows.rel(alice)

Out[10]: <KnowsRel (0x27e7810): (None)-[None:knows]->(None) {'since': '2012-01-01 00:00:00'}>

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neolixir

An Object-Relational Mapping (ORM) abstraction for Neo4j:

Declarative model definition
Polymorphic inheritance
Relationship abstraction
Strongly-typed properties

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Strongly-typed properties

Types: Boolean, String, Enum, Integer, Float, Numeric, DateTime

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Strongly-typed properties

Types: Boolean, String, Enum, Integer, Float, Numeric, DateTime

In [2]: class Student(Node):

...: name = String()

...: born = DateTime()

...: gpa = Numeric()

...: graduated = Boolean(default=False)

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Strongly-typed properties

Types: Boolean, String, Enum, Integer, Float, Numeric, DateTime

In [2]: class Student(Node):

...: name = String()

...: born = DateTime()

...: gpa = Numeric()

...: graduated = Boolean(default=False)

In [3]: bob = Student(name='Bob', born='1970-01-01', gpa='3.0')

In [4]: bob.name, bob.born, bob.gpa, bob.graduated

Out[4]: (u'Bob', datetime.datetime(1970, 1, 1, 0, 0), Decimal('3.0'), False)

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Strongly-typed properties

Types: Boolean, String, Enum, Integer, Float, Numeric, DateTime

In [2]: class Student(Node):

...: name = String()

...: born = DateTime()

...: gpa = Numeric()

...: graduated = Boolean(default=False)

In [3]: bob = Student(name='Bob', born='1970-01-01', gpa='3.0')

In [4]: bob.name, bob.born, bob.gpa, bob.graduated

Out[4]: (u'Bob', datetime.datetime(1970, 1, 1, 0, 0), Decimal('3.0'), False)

In [5]: bob.name = 123; bob.name

Out[5]: u'123'

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Strongly-typed properties

Types: Boolean, String, Enum, Integer, Float, Numeric, DateTime

In [2]: class Student(Node):

...: name = String()

...: born = DateTime()

...: gpa = Numeric()

...: graduated = Boolean(default=False)

In [3]: bob = Student(name='Bob', born='1970-01-01', gpa='3.0')

In [4]: bob.name, bob.born, bob.gpa, bob.graduated

Out[4]: (u'Bob', datetime.datetime(1970, 1, 1, 0, 0), Decimal('3.0'), False)

In [5]: bob.name = 123; bob.name

Out[5]: u'123'

In [8]: bob.gpa = 'foo'

ValueError: Invalid value for Numeric: foo

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neolixir

An Object-Relational Mapping (ORM) abstraction for Neo4j:

Declarative model definition
Polymorphic inheritance
Relationship abstraction
Strongly-typed properties
Session management

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Session management

In [6]: bob

Out[6]:

<Person (0x22f5050):

Id = None

Descriptors = ['knows', 'name']

Properties = {'name': u'Bob'}

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Session management

In [6]: bob

Out[6]:

<Person (0x22f5050):

Id = None

Descriptors = ['knows', 'name']

Properties = {'name': u'Bob'}

In [7]: metadata.session.commit()

In [8]: bob

Out[8]:

<Person (0x22f5050):

Id = 5433

Descriptors = ['knows', 'name']

Properties = {'name': u'Bob', '__class__': 'Person'}

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Session management

In [9]: bob.knows.append(Person(name='Alice'))

Out[9]: <Relationship (0x237ccd0): (5433)-[None:knows]->(None) {}>

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Session management

In [9]: bob.knows.append(Person(name='Alice'))

Out[9]: <Relationship (0x237ccd0): (5433)-[None:knows]->(None) {}>

In [10]: metadata.session.commit()

In [11]: bob.knows.rels()

Out[11]: [<Relationship (0x237ccd0): (5433)-[2706:knows]->(5434) {'__class__': 'Relationship'}>]

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Session management

In [9]: bob.knows.append(Person(name='Alice'))

Out[9]: <Relationship (0x237ccd0): (5433)-[None:knows]->(None) {}>

In [10]: metadata.session.commit()

In [11]: bob.knows.rels()

Out[11]: [<Relationship (0x237ccd0): (5433)-[2706:knows]->(5434) {'__class__': 'Relationship'}>]

In [12]: bob.knows

Out[12]:

[<Person (0x23851d0):

Id = 5434

Descriptors = ['knows', 'name']

Properties = {'name': u'Alice', '__class__': 'Person'}

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Session management

In [15]: bob

Out[15]:

<Person (0x22f5050):

Id = 5433

Descriptors = ['knows', 'name']

Properties = {'name': u'Bob', '__class__': 'Person'}

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Session management

In [15]: bob

Out[15]:

<Person (0x22f5050):

Id = 5433

Descriptors = ['knows', 'name']

Properties = {'name': u'Bob', '__class__': 'Person'}

In [16]: Node.get(5433)

Out[16]:

<Person (0x22f5050):

Id = 5433

Descriptors = ['knows', 'name']

Properties = {'name': u'Bob', '__class__': 'Person'}

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Session management

In [16]: Node.get(5433)

Out[16]:

<Person (0x22f5050):

Id = 5433

Descriptors = ['knows', 'name']

Properties = {'name': u'Bob', '__class__': 'Person'}

In [17]: metadata.session.clear()

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Session management

In [16]: Node.get(5433)

Out[16]:

<Person (0x22f5050):

Id = 5433

Descriptors = ['knows', 'name']

Properties = {'name': u'Bob', '__class__': 'Person'}

In [17]: metadata.session.clear()

In [18]: Node.get(5433)

Out[18]:

<Person (0x23ad990):

Id = 5433

Descriptors = ['born', 'knows', 'name']

Properties = {u'name': u'Bob', u'__class__': u'Person'}

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neolixir

An Object-Relational Mapping (ORM) abstraction for Neo4j:

Declarative model definition
Polymorphic inheritance
Relationship abstraction
Strongly-typed properties
Session management
Query abstraction

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Query abstraction

In [21]: Person.query.count()

Out[21]: 2

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Query abstraction

In [21]: Person.query.count()

Out[21]: 2

In [22]: Person.query.string

Out[22]: 'match (instance:Person) return instance'

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Query abstraction

In [21]: Person.query.count()

Out[21]: 2

In [22]: Person.query.string

Out[22]: 'match (instance:Person) return instance'

In [23]: Person.query.append('where instance.name = "Bob" return instance').string

Out[23]: 'match (instance:Person) where instance.name = "Bob" return instance'

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Query abstraction

In [21]: Person.query.count()

Out[21]: 2

In [22]: Person.query.string

Out[22]: 'match (instance:Person) return instance'

In [23]: Person.query.append('where instance.name = "Bob" return instance').string

Out[23]: 'match (instance:Person) where instance.name = "Bob" return instance'

In [24]: Person.query.append('where instance.name = "Bob" return instance').execute()

Out[24]:

[[<Person (0x23ad990):

Id = 5433

Descriptors = ['born', 'knows', 'name']

Properties = {u'name': u'Bob', u'__class__': u'Person'}

>]]

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neolixir

An Object-Relational Mapping (ORM) abstraction for Neo4j:

Declarative model definition
Polymorphic inheritance
Relationship abstraction
Strongly-typed properties
Session management
Query abstraction
Easy to use!

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neolixir

Current state:

Stable Python 2.7 code base
Used in production for over 3 years
Comprehensive test suite

In the near future:

Complete documentation, PyPI release
Python 3 support and tests
Neo4j 3.0 support, new features, etc...

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