GraphAcademy

Cypher

unique constraint

A Full definition for constraint (opens in a new tab)A rule the database enforces on every node or relationship with a given label or type, rejecting any write that breaks it. that permits only one Full definition for node (opens in a new tab)A vertex in a graph. In a property graph it can carry labels and properties. or Full definition for relationship (opens in a new tab)A named, directed connection between two nodes. Every relationship has a type, a start node and an end node. with a given Full definition for property (opens in a new tab)A named value stored on a node or a relationship. value for its Full definition for label (opens in a new tab)A tag on a node that groups it with other nodes of the same kind. A node can carry more than one. or type.

Example

No two (:Movie) nodes may hold the same movieId.

cypher
CREATE CONSTRAINT Movie_movieId_unique IF NOT EXISTS
FOR (m:Movie) REQUIRE m.movieId IS UNIQUE

A write creating a second (:Movie) with a movieId already in the graph is rejected, and its transaction fails. A (:Movie) carrying no movieId at all is stored, because the constraint compares the values that exist.

Lessons that use this term

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9 lessons use this term. Results are ordered by term density.

Using Neo4j with Python5 mentions

  • Handling Database ErrorsBest practicescommon scenario is dealing with constraint violations when inserting data. A unique constraint ensures that a property value is unique across all nodes with a specific4 mentions
  • Handling errorsBest practicesof the setup, you have added a unique constraint on the email property for the1 mention

Using Neo4j with .NET3 mentions

  • Error handlingBest practicescommon scenario is dealing with constraint violations when inserting data. A unique constraint ensures that a property value is unique across all nodes with a specific3 mentions

Using Neo4j with Java4 mentions

  • Handling errorsBest practicesof the setup, you have added a unique constraint on the email property for the1 mention
  • Handling Database ErrorsBest practicescommon scenario is dealing with constraint violations when inserting data. A unique constraint ensures that a property value is unique across all nodes with a specific3 mentions

Using Neo4j with LangChain3 mentions

  • Neo4jGraphNeo4j and LangChainUser: Has an index on name and a unique constraint on3 mentions

Importing CSV data into Neo4j2 mentions

  • Unique IDs and ConstraintsCreating Nodes, Properties, and Relationshipssyntax for creating a unique constraint on a property2 mentions

Importing Data into Neo4j Workshop1 mention

  • Unique IDs and ConstraintsNeo4j Data Importerthe unique ID for the Movie node to movieId, a unique constraint named movieId_Movie_uniq is created1 mention

Importing Data Fundamentals1 mention

  • Unique IDs and ConstraintsNeo4j Import toolthe unique ID for the Movie node to movieId, a unique constraint named movieId_Movie_uniq is created1 mention

Related terms

constraint
A rule the database enforces on every node or relationship with a given label or type, rejecting any write that breaks it.9 shared lessons
Data Importer
The Neo4j tool for loading CSV files into a graph by mapping their columns onto nodes and relationships.1 shared lesson
label
A tag on a node that groups it with other nodes of the same kind. A node can carry more than one.8 shared lessons
driver
The client library an application uses to connect to Neo4j and run Cypher.3 shared lessons
property
A named value stored on a node or a relationship.9 shared lessons
retriever
A component that searches a data source and returns the information relevant to a query. Often used to provide context for a language model.1 shared lesson
index
A structure over a property. The database reads it to find nodes or relationships by property value, rather than scanning every one.3 shared lessons
transaction
A unit of work that either succeeds in full or leaves no trace.2 shared lessons

All glossary terms