org.hibernate.ogm.datastore.neo4j.dialect.impl

Class CypherCRUD

java.lang.Object

org.hibernate.ogm.datastore.neo4j.dialect.impl.CypherCRUD

public class CypherCRUD
extends Object

Provides a way to create, remove and look for nodes and relationships using the cypher query language.

A node is created using an EntityKey. A node is labeled with NodeLabel.ENTITY and with the value returned by EntityKey.getTable(). The properties names and values of the node are the corresponding values of EntityKey.getColumnNames() and EntityKey.getColumnValues()

A relationship is created using an AssociationKey and a RowKey. The type of a new relationship is the value returned by AssociationKey.getCollectionRole(). The names and values of the properties of the relationship are the corresponding RowKey.getColumnNames() and RowKey.getColumnValues().

This class must be thread-safe since it's used by the dialect as a reference.

Author:

Davide D'Alto <davide@hibernate.org>

Constructor Summary

Constructors

Constructor and Description
CypherCRUD(org.neo4j.graphdb.GraphDatabaseService graphDb)

Method Summary

Methods

Modifier and Type	Method and Description
org.neo4j.graphdb.Node	createNodeUnlessExists(Key key, NodeLabel label) Find a node or create it if it doesn't exist.
org.neo4j.cypher.javacompat.ExecutionResult	executeQuery(String query, Map<String,Object> parameters)
org.neo4j.graphdb.Node	findNode(Key key) Find the node representing the Key.
org.neo4j.graphdb.Node	findNode(Key key, NodeLabel label) Find the node representing the entity key.
org.neo4j.graphdb.ResourceIterator<org.neo4j.graphdb.Node>	findNodes(String tableName) Query example:
org.neo4j.graphdb.Relationship	findRelationship(AssociationKey associationKey, RowKey rowKey) Query example:
static org.neo4j.graphdb.RelationshipType	relationshipType(AssociationKey associationKey) Converts the association key into the type of the relationship.
void	remove(AssociationKey associationKey) Removes the relationship(s) representing the given association.
void	remove(AssociationKey associationKey, RowKey rowKey) Removes the relationship representing the given association row.
void	remove(EntityKey entityKey) Remove the node and all the relationships connected to it.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CypherCRUD

public CypherCRUD(org.neo4j.graphdb.GraphDatabaseService graphDb)

Method Detail

findRelationship

public org.neo4j.graphdb.Relationship findRelationship(AssociationKey associationKey,
                                              RowKey rowKey)

Query example:

 MATCH (n) - [r:owners {`owner_id`: {0}} }] - ()
 RETURN r

Parameters:

associationKey - identify the type of the relationship

rowKey - identify the relationship

Returns:

the corresponding relationship

findNode

public org.neo4j.graphdb.Node findNode(Key key)

Find the node representing the Key.

 MATCH (n:Table {`id`: {0} })
 

Parameters:

key - representing the node

Returns:

the corresponding Node or null

findNode

public org.neo4j.graphdb.Node findNode(Key key,
                              NodeLabel label)

Find the node representing the entity key.

 MATCH (n:ENTITY:Table {`id`: {0} })
 

Parameters:

key - representing the node

Returns:

the corresponding Node or null

remove

public void remove(EntityKey entityKey)

Remove the node and all the relationships connected to it. Query example:

 MATCH (n:ENTITY:Table {`id`: {0}})
 OPTIONAL MATCH (n) - [r] - ()
 DELETE r,n

Parameters:

entityKey - of the entity to remove

findNodes

public org.neo4j.graphdb.ResourceIterator<org.neo4j.graphdb.Node> findNodes(String tableName)

Query example:

 MATCH (n:`tableName`) RETURN n

Returns:

the ResourceIterator with the results

createNodeUnlessExists

public org.neo4j.graphdb.Node createNodeUnlessExists(Key key,
                                            NodeLabel label)

Find a node or create it if it doesn't exist. Query example:

 MERGE (n:ENTITY:Table {`id`: {0} })
 RETURN n

Parameters:

key - identify the type of the relationship

Returns:

the resulting node

relationshipType

public static org.neo4j.graphdb.RelationshipType relationshipType(AssociationKey associationKey)

Converts the association key into the type of the relationship.

Parameters:

associationKey - the identifier of the association

Returns:

the corresponding RelationshipType

remove

public void remove(AssociationKey associationKey)

Removes the relationship(s) representing the given association. If the association refers to an embedded entity (collection), the referenced entity/ies are removed as well. Query example:

 MATCH (n) - [r:collectionRole { 'associationKey_column_name': {0}}] - ()
 DELETE r

 MATCH (n) - [r:collectionRole { 'associationKey_column_name': {0}}] - (x:EMBEDDED)
 DELETE r, x
 

remove

public void remove(AssociationKey associationKey,
          RowKey rowKey)

Removes the relationship representing the given association row. If the association row refers to an embedded entity, the referenced entity is removed as well. Query example:

 MATCH (n) - [r:collectionRole { 'rowkey_column_name': {0}}] - ()
 DELETE r

 MATCH (n) - [r:collectionRole { 'rowkey_column_name': {0}}] - (x:EMBEDDED)
 DELETE r, x
 

executeQuery

public org.neo4j.cypher.javacompat.ExecutionResult executeQuery(String query,
                                                       Map<String,Object> parameters)