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Error Messages for Neo4j Database Interfaces

The MATLAB® interface to Neo4j®, the Database Toolbox™ Interface for Neo4j Bolt Protocol, and the Neo4j database return error messages.

The Neo4j database error messages always have a status code that starts with Neo.ClientError. To troubleshoot these errors, consult the Neo4j Documentation.

The MATLAB interface to Neo4j and the Database Toolbox Interface for Neo4j Bolt Protocol return error messages in plain text. This table describes how to address common errors you can encounter while working with both interfaces.

Error MessageProbable CauseResolution

Invalid connection.

The Neo4j database connection is invalid.

Connect to the Neo4j database using neo4j.

Unable to connect. Please try again.

The Neo4j database connection is invalid.

Connect to the Neo4j database using neo4j.

No Nodes found with matching criteria.

The search cannot find nodes for the specified node label or property keys and values.

Verify the node label or property keys and values. Then, run searchNode.

Unable to find “relationship” relationships for node with id “node identifier” in database.

The search cannot find relationships for the specified relationships and node in the Neo4j database.

Verify the origin node and direction. Then, run searchRelation.

No node labels found.

The Neo4j database has no node labels.

Open the Neo4j database and add node labels. For details, see the Neo4j Operations Manual in the Neo4j Documentation. Then, run nodeLabels.

No relationship types found.

The Neo4j database has no relationship types.

Open the Neo4j database and add relationship types. For details, see the Neo4j Operations Manual in the Neo4j Documentation. Then, run relationTypes.

No property keys found.

The Neo4j database has no property keys.

Open the Neo4j database and add property keys. For details, see the Neo4j Operations Manual in the Neo4j Documentation. Then, run propertyKeys.

Unable to execute Cypher® query.

The Cypher query is invalid.

Verify the Cypher query. Then, run executeCypher. For details about writing Cypher queries, see Cypher Query Language.

Unable to find one or more of the specified nodes in the database.

When you update or delete nodes, the specified node does not exist in the Neo4j database. Or, when you create a relationship, the specified start node or end node does not exist in the Neo4j database.

Find nodes in the Neo4j database using the searchNode function.

Unable to find one or more of the specified relations in the database.

When you update or delete relationships, the specified relationship does not exist in the Neo4j database.

Find relationships in the Neo4j database using the searchRelation function.

One or more nodes have relations. Explicitly delete relations. Or, to delete both nodes and all associated relations, set 'DeleteRelations' to true.

When you delete nodes, the specified nodes have associated relationships.

Delete the node and its associated relationships by using this syntax of the deleteNode function:

deleteNode(neo4jconn,node,'DeleteRelations',true)

Duplicate nodes not supported.

When you create or update a node, you cannot specify duplicate nodes.

Remove duplicate nodes from the input arguments of the function you execute.

Duplicate relations not supported.

When you create or update a relationship, you cannot specify duplicate relationships.

Remove duplicate relationships from the input arguments of the function you execute.

Database Toolbox Interface for Neo4j Bolt Protocol has not been installed. Open Add-On Explorer to install the add-on.

You specify the Bolt database connection URL that starts with the bolt:// protocol identifier and the Database Toolbox Interface for Neo4j Bolt Protocol is not installed.

Install the Database Toolbox Interface for Neo4j Bolt Protocol. For details, see Database Toolbox Interface for Neo4j Bolt Protocol Installation.

See Also

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