USE

The USE clause determines which graph a query, or query part, is executed against. It is supported for queries and schema commands.

With Neo4j Drivers, do not rely on the USE clause to specify the database against which a query should run. Drivers expect the database name to be specified as a parameter in the query’s function call.

Syntax

The USE clause can only appear as the prefix of schema commands, or as the first clause of queries:

USE <graph>
<other clauses>

Where <graph> refers to the name or alias of a database in the DBMS.

Composite database syntax

When running queries against a composite database, the USE clause can also appear as the first clause of:

  • Union parts:

    USE <graph>
<other clauses>
  UNION
USE <graph>
<other clauses>

  • Subqueries:

    CALL {
  USE <graph>
  <other clauses>
}

    In subqueries, a USE clause may appear as the second clause, if directly following an importing WITH clause.

When executing queries against a composite database, the USE clause must only refer to graphs that are part of the current composite database.

Examples

Query a graph

In this example it is assumed that the DBMS contains a database named myDatabase:

Query
USE myDatabase
MATCH (n) RETURN n

Query a composite database constituent graph

In this example it is assumed that the DBMS contains a composite database named myComposite, which includes an alias named myConstituent:

Query
USE myComposite.myConstituent
MATCH (n) RETURN n

Query a composite database constituent graph dynamically

The built-in function graph.byName() can be used in the USE clause to resolve a constituent graph from a string value containing the qualified name of a constituent.

This example uses a composite database named myComposite that includes an alias named myConstituent:

Query
USE graph.byName('myComposite.myConstituent')
MATCH (n) RETURN n

The argument can be any expression that evaluates to the name of a constituent graph - for example a parameter:

Query
USE graph.byName($graphName)
MATCH (n) RETURN n

Query a composite database constituent using elementId

The graph.byElementId() function (introduced in Neo4j 5.13), can be used in the USE clause to resolve a constituent graph to which a given element id belongs. In the below example, it is assumed that the DBMS contains a composite database constituent, which contains the element id 4:c0a65d96-4993-4b0c-b036-e7ebd9174905:0. If the constituent database is not a standard database in the DBMS an error will be thrown: .Query

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