Neo4j

Neo4j Course

Docker installation on WSL

Pre-request: Of course you need to install Linux on WSL and install docker on the Linux

1. Startup and login to wsl system (In my laptop it's Ubuntu)
   wsl -d Ubuntu
2. Run neo4j:latest`` using network host mode docker run -d --name neo4j --network host neo4j`
3. Get the wsl Ubuntu ip using ip
   It's 172.29.106.157 in my case
4. Access the neo4j server
   http://172.29.106.157:7474/browser/
   The default user and password is neo4j/neo4j
5. You can now do the experiment right now.

Key Concepts

• Refactor /
• Noun : Camel Case
• Verb : Upper Case
• Property: Lower Case
• Relationship
• Label
• Specialized Relationship

---

Query All and Delete

MATCH (n) DETACH DELETE n;

Movie Exampole

---

Creating three movies and four actors

MERGE (:Movie {title: 'Apollo 13', tmdbId: 568, released: '1995-06-30', imdbRating: 7.6, genres: ['Drama', 'Adventure', 'IMAX']})
MERGE (:Person {name: 'Tom Hanks', tmdbId: 31, born: '1956-07-09'})
MERGE (:Person {name: 'Meg Ryan', tmdbId: 5344, born: '1961-11-19'})
MERGE (:Person {name: 'Danny DeVito', tmdbId: 518, born: '1944-11-17'})
MERGE (:Person {name: 'Jack Nicholson', tmdbId: 514, born: '1937-04-22'})
MERGE (:Movie {title: 'Sleepless in Seattle', tmdbId: 858, released: '1993-06-25', imdbRating: 6.8, genres: ['Comedy', 'Drama', 'Romance']})
MERGE (:Movie {title: 'Hoffa', tmdbId: 10410, released: '1992-12-25', imdbRating: 6.6, genres: ['Crime', 'Drama']})

Add two users

MERGE (:User {name: 'Sandy Jones', userId: 534})
MERGE (:User {name: 'Clinton Spencer', userId: 105})

---

Creating relationship

MATCH (apollo:Movie {title: 'Apollo 13'})
MATCH (tom:Person {name: 'Tom Hanks'})
MATCH (meg:Person {name: 'Meg Ryan'})
MATCH (danny:Person {name: 'Danny DeVito'})
MATCH (sleep:Movie {title: 'Sleepless in Seattle'})
MATCH (hoffa:Movie {title: 'Hoffa'})
MATCH (jack:Person {name: 'Jack Nicholson'})

// create the relationships between nodes
MERGE (tom)-[:ACTED_IN {role: 'Jim Lovell'}]->(apollo)
MERGE (tom)-[:ACTED_IN {role: 'Sam Baldwin'}]->(sleep)
MERGE (meg)-[:ACTED_IN {role: 'Annie Reed'}]->(sleep)
MERGE (danny)-[:ACTED_IN {role: 'Bobby Ciaro'}]->(hoffa)
MERGE (danny)-[:DIRECTED]->(hoffa)
MERGE (jack)-[:ACTED_IN {role: 'Jimmy Hoffa'}]->(hoffa)

Query all data

MATCH (n) RETURN n

Conditional Query

MATCH (p:Person)-[:ACTED_IN]-(m:Movie)
WHERE m.title = 'Sleepless in Seattle'
RETURN p.name AS Actor

MATCH (u:User)-[:RATED]-(m:Movie)
WHERE m.title = 'Apollo 13'
RETURN count(*) AS `Number of reviewers`

MATCH (p:Person)-[:ACTED_IN]-(m:Movie)
WHERE m.title = 'Hoffa'
RETURN  p.name AS Actor, p.born as `Year Born` ORDER BY p.born DESC LIMIT 1

---

Label Data

MATCH (p:Person)
WHERE exists ((p)-[:ACTED_IN]-())
SET p:Actor

PROFILE

PROFILE MATCH (p:Person)-[:ACTED_IN]-()
WHERE p.born < '1950'
RETURN p.name

Modify Nodes

MATCH (apollo:Movie {title: 'Apollo 13', tmdbId: 568, released: '1995-06-30', imdbRating: 7.6, genres: ['Drama', 'Adventure', 'IMAX']})
MATCH (sleep:Movie {title: 'Sleepless in Seattle', tmdbId: 858, released: '1993-06-25', imdbRating: 6.8, genres: ['Comedy', 'Drama', 'Romance']})
MATCH (hoffa:Movie {title: 'Hoffa', tmdbId: 10410, released: '1992-12-25', imdbRating: 6.6, genres: ['Crime', 'Drama']})
MATCH (casino:Movie {title: 'Casino', tmdbId: 524, released: '1995-11-22', imdbRating: 8.2, genres: ['Drama','Crime']})
SET apollo.languages = ['English']
SET sleep.languages =  ['English']
SET hoffa.languages =  ['English', 'Italian', 'Latin']
SET casino.languages =  ['English']

---

Unwind

• This code iterates through all Movie nodes and creates a Language node for each language it finds and then creates the relationship between the Movie node and Language node using the IN_LANGUAGE relationship. It uses the Cypher UNWIND clause to separate each element of the languages property list into a separate row value that is processed later in the query.

MATCH (m:Movie)
UNWIND m.languages AS language
WITH  language, collect(m) AS movies
MERGE (l:Language {name:language})
WITH l, movies
UNWIND movies AS m
WITH l,m
MERGE (m)-[:IN_LANGUAGE]->(l);
MATCH (m:Movie)
SET m.languages = null

---

Specialized Relationship

MATCH (n:Actor)-[:ACTED_IN]->(m:Movie)
CALL apoc.merge.relationship(n,
  'ACTED_IN_' + left(m.released,4),
  {},
  {},
  m ,
  {}
) YIELD rel
RETURN count(*) AS `Number of relationships merged`;