What is constraint?

Example

Every (:Person) must hold a name.

cypher

CREATE CONSTRAINT Person_name_exists IF NOT EXISTS
FOR (p:Person) REQUIRE p.name IS NOT NULL

A write creating a (:Person) without a name is rejected, and so is one removing the name from a person already in the graph. Either way the transaction fails and nothing is stored.

Lessons that use this term

The lesson and course links below open in a new tab.

66 lessons use this term. The 40 with the highest term density are listed here.

Cypher Indexes and Constraints195 mentions

Managing Constraints in Neo4jUsing Constraints in Neo4jconstraints in the graph19 mentions
Creating Existence Constraints on Relationship PropertiesUsing Constraints in Neo4jExistence constraints are only available in Enterprise18 mentions
Creating Existence Constraints for Node PropertiesUsing Constraints in Neo4jExistence constraints are only available in Enterprise21 mentions
Creating Node Key ConstraintsUsing Constraints in Neo4jNode key is a specialized type of constraint for the properties of a21 mentions
Creating Uniqueness ConstraintsUsing Constraints in Neo4jmovie graph, these constraints31 mentions
Creating Existence Constraints for Relationship PropertiesUsing Constraints in Neo4jprevious lesson, you created the existence constraint for the rating property for the RATED relationships in the6 mentions
Constraints in Neo4jUsing Constraints in Neo4jconstraint is implemented internally as an28 mentions
Creating Uniqueness ConstraintsUsing Constraints in Neo4jreal application, you would create uniqueness constraints for nodes prior to loading the7 mentions
Creating a Node Key ConstraintUsing Constraints in Neo4jthe sandbox on the right, modify the code to a Node key constraint for the name and url properties in the5 mentions
Creating Existence Constraints for Node propertiesUsing Constraints in Neo4jreal application, you would create existence constraints for nodes prior to loading the7 mentions
Constraints and Indexes in Neo4jIndexes and Constraints in Neo4jconstraint is implemented internally as an index and is used to constrain what is added to the6 mentions
Identifying What Constraints and Indexes to CreateIndexes and Constraints in Neo4juse constraints15 mentions
Creating a RANGE Index on a Node PropertyUsing Indexes in Neo4jan index, RANGE index p:Person(name, url), the Node key constraint that you created3 mentions
Dropping ConstraintsUsing Constraints in Neo4jthe names of these constraints in the graph and drop1 mention
Creating Single Property IndexesUsing Indexes in Neo4jhave already learned how to list the constraints in the4 mentions
Getting the Most Out of IndexesIndex Usage in Neo4jIndex type | Default implementation | | --- | --- | | Uniqueness constraint | range-1.0 | | Node key | range-1.0 | | RANGE | range-1.0 | | Composite index | range-1.0 | | TEXT index | text-1.01 mention

Importing CSV data into Neo4j24 mentions

Unique IDs and ConstraintsCreating Nodes, Properties, and Relationshipscan add constraints to your database to stop the creation of nodes with duplicate12 mentions
Congratulations and Next StepsImporting data considerationsCreate constraints on3 mentions
Building an Import ProcessImporting data considerationsCreate Person and Movie constraints Import data from persons.csv and create Person nodes Import data from movies.csv and create Movie nodes -5 mentions
Adding Movie NodesCreating Nodes, Properties, and Relationshipsa constraint to ensure that there are no duplicate4 mentions

Graph Type Schema Enforcement33 mentions

Constraints and Extending Graph TypesSchema Enforcement with Graph Typesthis lesson, you will add property constraints to enforce uniqueness and mandatory fields, then use the ADD command to build on an existing graph type without16 mentions
Extend the Graph TypeSchema Enforcement with Graph Typesthe previous lesson, you learned how graph types express property constraints, the difference between SET and ADD, and how to define relationship element1 mention
Managing Graph TypesSchema Enforcement with Graph Typesnow have a graph type with node types, relationship types, and constraints10 mentions
Complete Recommendations SchemaSchema Enforcement with Graph Typeshave learned how to define node types, relationship types, and constraints2 mentions

Using Neo4j with Go2 mentions

Error handlingBest practicesConnection errors - Network issues, authentication failures Constraint errors - Violations of database constraints Transaction errors - Deadlocks, timeout issues Query errors -2 mentions

Importing Data Fundamentals10 mentions

Unique IDs and ConstraintsNeo4j Import toolthis lesson, you will explore the importance of unique IDs, constraints and7 mentions
Import tool ConsiderationsNeo4j Import toolyou should be aware of the constraints of using the Import2 mentions

Importing Data into Neo4j Workshop7 mentions

Unique IDs and ConstraintsNeo4j Data Importerthis lesson, you will explore the importance of unique IDs, constraints and6 mentions

Using Neo4j with .NET3 mentions

Error handlingBest practices—Raised when the Cypher syntax is invalid or a constraint is violated AuthenticationException —Raised when authentication fails ServiceUnavailableException —Raised when3 mentions

Using Neo4j with Python4 mentions

Handling Database ErrorsBest practicesRaised when the Cypher syntax is invalid ConstraintError - Raised when a constraint unique or other is violated AuthError - Raised when authentication fails TransientError - Raised when the3 mentions
Handling errorsBest practiceswith the same email address, and instead relies on the database to enforce the constraint1 mention

Using Neo4j with Java3 mentions

Handling errorsBest practiceswith the same email address, and instead relies on the database to enforce the constraint1 mention
Handling Database ErrorsBest practicescommon scenario is dealing with constraint violations when inserting2 mentions

Building Neo4j Applications with Spring Data4 mentions

The Data Domain and the Graph ModelThe Application Domain Modelis because each model must fit the constraints of the system it is designed3 mentions

LOAD CSV Data Import17 mentions

Import a Complete DatasetImporting with LOAD CSVdrop any existing constraints so you can recreate them as part of your8 mentions
Idempotent Imports and Error HandlingImporting with LOAD CSVuniqueness constraint creates an6 mentions

Neo4j Management, Optimization, and Refactoring Workshop10 mentions

Normalizing a property to a nodeGraph refactoringcan add a node key constraint to ensure data9 mentions

GraphRAG Hackathon3 mentions

Querying with CypherIntroduction to GraphRAGUse MATCH, WHERE, and MERGE to query and write data Create indexes and constraints to keep your graph performant Traverse multi-hop paths — the foundation of GraphRAG3 mentions

Graph Data Modeling Fundamentals2 mentions

Enforcing Data ModelsTesting the ModelConstraints- key, uniqueness, and existence rules on2 mentions

Context Graphs: Agent Memory with Neo4j1 mention

Store your first memoryIntroduction to Agent Memorytakes a few seconds longer than later ones, because the library creates its constraints and vector indexes before writing1 mention

All glossary terms