Graph functions

graph.names()

Details
Syntax	`graph.names()`
Description	Lists the names of graphs in the current database.
Returns	`LIST<STRING>`

Considerations
`graph.names()` is only supported on composite databases.

Example 1. graph.names()

Setup

CREATE DATABASE dba;
CREATE DATABASE dbb;
CREATE DATABASE dbc;
CREATE COMPOSITE DATABASE composite;
CREATE ALIAS composite.first FOR DATABASE dba;
CREATE ALIAS composite.second FOR DATABASE dbb;
CREATE ALIAS composite.third FOR DATABASE dbc;

Query

RETURN graph.names() AS name

The names of all graphs on the current composite database are returned.

Result
name
`"composite.first"`
`"composite.second"`
`"composite.third"`
Rows: 3

graph.propertiesByName()

Details
Syntax	`graph.propertiesByName(graphName)`
Description	Returns the `MAP` of properties associated with a graph.
Arguments	Name	Type	Description
	`graphName`	`STRING`	The name of the graph from which all associated properties will be returned.
Returns	`MAP`

Considerations
`graph.propertiesByName()` is only supported on composite databases.
The properties in the returned `MAP` are set on the aliasthat adds the graph as a constituent of a composite database.

Example 2. graph.propertiesByName()

Setup

CREATE DATABASE dba;
CREATE DATABASE dbb;
CREATE DATABASE dbc;
CREATE COMPOSITE DATABASE composite;
CREATE ALIAS composite.first FOR DATABASE dba
  PROPERTIES {number: 1, tags: ['A', 'B']};
CREATE ALIAS composite.second FOR DATABASE dbb
  PROPERTIES {number: 0, tags: ['A']};
CREATE ALIAS composite.third FOR DATABASE dbc
  PROPERTIES {number: 2, tags: ['B', 'C']};

Query

UNWIND graph.names() AS name
RETURN name, graph.propertiesByName(name) AS props

Properties for all graphs on the current composite database are returned.

Result
name	props
`"composite.first"`	`{number: 1, tags: ["A", "B"]}`
`"composite.second"`	`{number: 0, tags: ["A"]}`
`"composite.third"`	`{number: 2, tags: ["B", "C"]}`
Rows: 3

Query

UNWIND graph.names() AS name
WITH name, graph.propertiesByName(name) AS props
WHERE "A" IN props.tags
CALL () {
  USE graph.byName(name)
  MATCH (n)
  RETURN n
}
RETURN n

Returns all nodes from a subset of graphs that have a tags property containing "A".

The above query uses an empty variable scope clause: CALL () { … } (introduced in Neo4j 5.23). If you are using an older version of Neo4j, use CALL { … } instead. For more information, see CALL subqueries → Importing variables.

graph.byName()

Details
Syntax	`graph.byName(name)`
Description	Returns the graph reference of the given name.
Arguments	Name	Type	Description
	`name`	`STRING`	The name of the graph to be resolved.
Returns	`GRAPH`

Considerations
`graph.byName()` is only supported in the `USE` clause, on composite databases.

Example 3. graph.byName()

Query

UNWIND graph.names() AS graphName
CALL () {
  USE graph.byName(graphName)
  MATCH (n)
  RETURN n
}
RETURN n

Returns all nodes from all graphs on the current composite database.

graph.byElementId()

Details
Syntax	`graph.byElementId(elementId)`
Description	Returns the graph reference with the given element id.
Arguments	Name	Type	Description
	`elementId`	`STRING`	An element id of a node or relationship.
Returns	`GRAPH`

Considerations
If the constituent database is not a standard database in the DBMS, an error will be thrown.
`graph.byElementId()` is only supported in the `USE` clause.
`graph.byElementId()` is supported on both standard and composite databases.
On a standard database, a `USE` clause with `graph.byElementId()` cannot be combined with other `USE` clauses unless the subsequent `USE` clauses reference the same element id.

Example 4. graph.byElementId()

In this example, it is assumed that the DBMS contains a composite database constituent, which contains the element id 4:c0a65d96-4993-4b0c-b036-e7ebd9174905:0.

Query

USE graph.byElementId("4:c0a65d96-4993-4b0c-b036-e7ebd9174905:0")
MATCH (n) RETURN n