Using Cypher
Using Cypher
You can use the query language Cypher to interact with a Neo4j graph database.
You are you going to use Cypher to explore a graph database containing:
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Movies, actors and directors from The Movie Database (TMDB).
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Movie ratings by users of the website.
The graph contains Person and Movie nodes.
Each of Person node may have one or more outgoing ACTED_IN and DIRECTED relationships to a Movie node.
Movies are categorized into one or more genres, for example, Adventure, Animation, and, Comedy.
Movie nodes are connected to Genre nodes by an IN_GENRE relationship.
The graph also contains User nodes and over 100,000 movies ratings.
User nodes are connected to Movie nodes by a RATED relationship.
Explore the Graph
GraphAcademy has created a Neo4j database instance for you.
People
Run the following Cypher statement to find a Person node with the name attribute 'Tom Hanks'.
MATCH (n:Person)
WHERE n.name = 'Tom Hanks'
RETURN nEach Person node has an unique name property, as well as other properties such as bio and born.
View the node properties by selecting the node.
Expand the node’s relationships by doubling click the node.
You will see that there are ACTED_IN and DIRECTED relationships to Movie nodes.
Movies
Each Movie node has a unique title property, as well as other properties including plot, released and url.
Run the following Cypher statement to find the movie 'Toy Story' and the people who acted in the movie.
MATCH (m:Movie)<-[r:ACTED_IN]-(p:Person)
WHERE m.title = 'Toy Story'
RETURN m, r, p
The query uses the [ACTED_IN] relationship to find Person nodes who have a connection to the Movie node.
This Cypher statement uses the [IN_GENRE] relationship to find related Genre nodes.
MATCH (m:Movie)-[r:IN_GENRE]->(g:Genre)
WHERE m.title = 'Toy Story'
RETURN m, r, g
You can return tabular data by including the properties of the nodes.
MATCH (m:Movie)-[r:IN_GENRE]->(g:Genre)
WHERE m.title = 'Toy Story'
RETURN m.title, g.nameExperiment with these queries. Try and find different movies and people, for example, the Movie node "Babe" or the Person node "Emma Stone".
User Ratings
Review this Cypher statement before running it and predict what graph will be returned.
MATCH (u:User)-[r:RATED]->(m:Movie)
WHERE u.name = "Mr. Jason Love"
RETURN u, r, mClick here to reveal the result
The statement returns all the movies that have been rated by the user "Mr. Jason Love".
The rating the user has given for the movie is stored as a property on the RATED relationship.
Run this Cypher statement to return a table of movie ratings:
MATCH (u:User)-[r:RATED]->(m:Movie)
WHERE u.name = "Mr. Jason Love"
RETURN u.name, r.rating, m.titleThe properties are defined in the RETURN, for example u.name will return the name property of the User node.
| u.name | r.rating | m.title |
|---|---|---|
"Mr. Jason Love" |
3.0 |
"Houseguest" |
"Mr. Jason Love" |
3.0 |
"Ed Wood" |
"Mr. Jason Love" |
4.0 |
"Little Women" |
"Mr. Jason Love" |
4.0 |
"Interview with the Vampire: The Vampire Chronicles" |
"Mr. Jason Love" |
5.0 |
"Circle of Friends" |
Check Your Understanding
Node Labels
Which of the following are node labels that are used in the Movie recommendations graph?
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❏ ACTED_IN
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❏ DIRECTED
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✓ Movie
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✓ Person
Hint
The graph has two labels to represent people and movies.
Hint
The graph has Person and Movie node labels.
ACTED_IN and DIRECTED are types of relationship used to connect people to movies.
Summary
In this lesson, you learned explored the nodes and relationships in the movie recommendations dataset.
In the next lesson, you will learn how to find patterns in the data using Cypher.