Module org.neo4j.driver
Package org.neo4j.driver

Interface SimpleQueryRunner

All Known Subinterfaces:
QueryRunner, Session, Transaction, TransactionContext
public interface SimpleQueryRunner
Common interface for components that can execute Neo4j queries.

Important notes on semantics

queries run in the same QueryRunner are guaranteed to execute in order, meaning changes made by one query will be seen by all subsequent queries in the same QueryRunner.

However, to allow handling very large results, and to improve performance, result streams are retrieved lazily from the network. This means that when any of run(Query) methods return a result, the query has only started executing - it may not have completed yet. Most of the time, you will not notice this, because the driver automatically waits for queries to complete at specific points to fulfill its contracts.

Specifically, the driver will ensure all outstanding queries are completed whenever you:

As noted, most of the time, you will not need to consider this - your writes will always be durably stored as long as you either use the results, explicitly commit transactions or close the session you utilised using Session.close().

While these semantics introduce some complexity, it gives the driver the ability to handle infinite result streams (like subscribing to events), significantly lowers the memory overhead for your application and improves performance.

Since:
5.0
See Also:

  • Method Details

    • run

      Result run(String query, Value parameters)
      Run a query and return a result stream.

      This method takes a set of parameters that will be injected into the query by Neo4j. Using parameters is highly encouraged, it helps avoid dangerous cypher injection attacks and improves database performance as Neo4j can re-use query plans more often.

      This particular method takes a Value as its input. This is useful if you want to take a map-like value that you've gotten from a prior result and send it back as parameters.

      If you are creating parameters programmatically, run(String, Map) might be more helpful, it converts your map to a Value for you.

      Example

       

 Result result = session.run( "MATCH (n) WHERE n.name = $myNameParam RETURN (n)",
                                       Values.parameters( "myNameParam", "Bob" ) );
      Parameters:
      query - text of a Neo4j query
      parameters - input parameters, should be a map Value, see Values.parameters(Object...).
      Returns:
      a stream of result values and associated metadata

    • run

      Result run(String query, Map<String,Object> parameters)
      Run a query and return a result stream.

      This method takes a set of parameters that will be injected into the query by Neo4j. Using parameters is highly encouraged, it helps avoid dangerous cypher injection attacks and improves database performance as Neo4j can re-use query plans more often.

      This version of run takes a Map of parameters. The values in the map must be values that can be converted to Neo4j types. See Values.parameters(Object...) for a list of allowed types.

      Example

       

 Map<String, Object> parameters = new HashMap<String, Object>();
 parameters.put("myNameParam", "Bob");
 <p>
 Result result = session.run( "MATCH (n) WHERE n.name = $myNameParam RETURN (n)",
                                       parameters );
      Parameters:
      query - text of a Neo4j query
      parameters - input data for the query
      Returns:
      a stream of result values and associated metadata

    • run

      Result run(String query, Record parameters)
      Run a query and return a result stream.

      This method takes a set of parameters that will be injected into the query by Neo4j. Using parameters is highly encouraged, it helps avoid dangerous cypher injection attacks and improves database performance as Neo4j can re-use query plans more often.

      This version of run takes a Record of parameters, which can be useful if you want to use the output of one query as input for another.

      Parameters:
      query - text of a Neo4j query
      parameters - input data for the query
      Returns:
      a stream of result values and associated metadata

    • run

      Result run(String query)
      Run a query and return a result stream.
      Parameters:
      query - text of a Neo4j query
      Returns:
      a stream of result values and associated metadata

    • run

      Result run(Query query)
      Run a query and return a result stream.

      Example

       

 Query query = new Query( "MATCH (n) WHERE n.name = $myNameParam RETURN n.age" );
 Result result = session.run( query.withParameters( Values.parameters( "myNameParam", "Bob" )  ) );
      Parameters:
      query - a Neo4j query
      Returns:
      a stream of result values and associated metadata