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May 15, 2024
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add indexes and constraints content #36

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add indexes and constraints content
AlexicaWright May 15, 2024
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address PR comment
AlexicaWright May 15, 2024
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19 changes: 16 additions & 3 deletions documentation/movies.workspace.adoc
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Expand Up @@ -35,9 +35,6 @@ image::movie-model.png[]

[source,cypher]
----
CREATE CONSTRAINT movie_title IF NOT EXISTS FOR (m:Movie) REQUIRE m.title IS UNIQUE;
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please don't change it, it needs to stay here. other wise the performance will be affected as each MERGE needs to do a full label-scan to find the relevant nodes.

CREATE CONSTRAINT person_name IF NOT EXISTS FOR (p:Person) REQUIRE p.name IS UNIQUE;

MERGE (TheMatrix:Movie {title:'The Matrix'}) ON CREATE SET TheMatrix.released=1999, TheMatrix.tagline='Welcome to the Real World'

MERGE (Keanu:Person {name:'Keanu Reeves'}) ON CREATE SET Keanu.born=1964
Expand Down Expand Up @@ -702,6 +699,22 @@ MATCH path = (person)-[:ACTED_IN]->(m)<-[:DIRECTED]-(d)
RETURN path;
----

To aid query performance, you can add indexes to your data.
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Either move this to the beginning, but we should ensure that people execute this cypher-block, or keep it in the MERGE statement.

(The dataset you create in this guide is very small, but it is good practice to use indexes as they can greatly improve query performance when the datasets are larger.)

In this small dataset, you are mainly interested in names of people and titles of movies.
Run the following to add indexes on these properties

[source,cypher]
----
CREATE INDEX person_name FOR (p:Person) ON (p.name);
CREATE INDEX movie_title FOR (m:Movie) ON (m.title)
----

Note that you can also add constraints to your data to ensure uniqueness for example.
Adding constraints automatically adds a correpsonding index.
See link:https://neo4j.com/docs/cypher-manual/current/constraints/[Cypher Manual -> Constraints^] for more information.

In the next step, you will look for nodes and their properties.

== Find nodes
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