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Nov 17, 2025
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cypher-constraints-indexes - Update to reflect changes in Neo4j #428

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2137d7b
update to reflect changes in Neo4j
martinohanlon Nov 14, 2025
397ed43
post review change
martinohanlon Nov 14, 2025
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23 changes: 12 additions & 11 deletions ...es-constraints/modules/2-constraints/lessons/01-constraint-overview/lesson.adoc
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= Constraints in Neo4j
:type: video
:type: lesson
:order: 1
:sandbox: true

[.video]
video::N_m8Qb6vnfA[youtube,width=560,height=315]
// [.video]
// video::N_m8Qb6vnfA[youtube,width=560,height=315]

//https://youtu.be/N_m8Qb6vnfA

Expand All @@ -13,15 +13,16 @@ video::N_m8Qb6vnfA[youtube,width=560,height=315]

A constraint is implemented internally as an index.
It is used to constrain what is added to the graph.
There are three types of constraints you can define:

* Uniqueness for a single node property value or a set of node property values.
* Existence for a property of a node or relationship.
* Existence and uniqueness for a node property value or a set of node property values (Node key).
You can define link:https://neo4j.com/docs/cypher-manual/current/constraints/[different types of constraint^] that apply to nodes with a specific label or relationships of a type, including:

* Property uniqueness constraints - ensure that all values for a property are unique.
* Property existence constraints - ensure that a property exists.
* Key constraints - ensure that a combination of properties exists and is unique.

=== Uniqueness constraints

A uniqueness constraint can be defined for a property of a node with a given label.
A uniqueness constraint can be defined for a property.

For example, in the Movie graph, we uniquely identify every Person node.
To do this, we identify a property whose value will be unique for all nodes with the Person label.
Expand Down Expand Up @@ -128,11 +129,11 @@ RETURN p

You will learn how to create and test an existence constraint later in this module.

=== Node key constraint
=== Key constraint

A node key is a specialized type of constraint in the graph that enables you to define a set of properties for a node label that must:
A key is a specialized type of constraint in the graph that enables you to define a set of properties for a node label or relationship type that must:

. Exist for all nodes with that label.
. Exist for all nodes or relationships with that label or type.
. Be unique for all values.

For example, suppose you want to ensure that all Person nodes in the graph have unique values for Person.name and Person.tmdbId.
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10 changes: 5 additions & 5 deletions ...les/2-constraints/lessons/01-constraint-overview/questions/1-select-answer.adoc
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[.question]
= 1. What type of constraint can you define to ensure a _set of property values_ is unique?

* [ ] Uniqueness on a node property.
* [ ] Uniqueness on a property.
* [ ] Uniqueness on a set of relationship type properties.
* [x] Node key for a set of properties of a node label.
* [ ] Uniqueness key for a set of properties of a node label.
* [x] Key constraint for a set of properties.
* [ ] Uniqueness key for a set of properties.

[TIP,role=hint]
.Hint
====
There is one construct used to uniquely identify property values for a set of node labels.
There is one construct used to uniquely identify property values.
====

[TIP,role=solution]
.Solution
====
A Node key is used to ensure that a set of property values for all nodes of that label type are unique in the graph.
A key constraint is used to ensure that a set of property values for all nodes or relationships of that label or type are unique in the graph.
====
10 changes: 5 additions & 5 deletions ...les/2-constraints/lessons/01-constraint-overview/questions/2-select-answer.adoc
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[.question]
= 2. What type of constraint can be created for node properties or relationship properties?
= 2. What type of constraint can be created?

* [ ] Node key
* [ ] Uniqueness
* [x] Key
* [x] Uniqueness
* [x] Existence
* [ ] IS NULL

[TIP,role=hint]
.Hint
====
There is only one type of constraint that you can define on node properties or relationship properties.
You cannot create a constraint to ensure a property doesn't exist.
====

[TIP,role=solution]
.Solution
====
The correct answer is Existence constraint.
The correct answer are Key, Uniqueness, and Existence.
====