org.neo4j.driver.v1

Interface StatementRunner

All Known Subinterfaces:

Session, Transaction

public interface StatementRunner

Common interface for components that can execute Neo4j statements.

Important notes on semantics

Statements run in the same StatementRunner are guaranteed to execute in order, meaning changes made by one statement will be seen by all subsequent statements in the same StatementRunner. However, to allow handling very large results, and to improve performance, result streams are retrieved lazily. This means that when any of the run(Statement) methods return a result, the statement 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 statements to complete at specific points to fulfill its contracts. Specifically, the driver will ensure all outstanding statements are completed whenever you:

• Read from or discard a result, for instance via StatementResult.next(), StatementResult.consume().
• Explicitly commit a transaction using Transaction.close()
• Return a session to the pool using Session.close()

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 return the session you used to the pool 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:

1.0

See Also:

Session, Transaction

Method Summary

Methods

Modifier and Type	Method and Description
StatementResult	run(Statement statement) Run a statement and return a result stream.
StatementResult	run(String statementTemplate) Run a statement and return a result stream.
StatementResult	run(String statementTemplate, Map<String,Object> statementParameters) Run a statement and return a result stream.
StatementResult	run(String statementTemplate, Record statementParameters) Run a statement and return a result stream.
StatementResult	run(String statementTemplate, Value parameters) Run a statement and return a result stream.
org.neo4j.driver.v1.types.TypeSystem	typeSystem()

Method Detail

run

StatementResult run(String statementTemplate,
                  Value parameters)

Run a statement and return a result stream. This method takes a set of parameters that will be injected into the statement 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

 StatementResult cursor = session.run( "MATCH (n) WHERE n.name = {myNameParam} RETURN (n)",
                                       Values.parameters( "myNameParam", "Bob" ) );
 
 

Parameters:

statementTemplate - text of a Neo4j statement

parameters - input parameters, should be a map Value, see Values.parameters(Object...).

Returns:

a stream of result values and associated metadata

run

StatementResult run(String statementTemplate,
                  Map<String,Object> statementParameters)

Run a statement and return a result stream. This method takes a set of parameters that will be injected into the statement 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");

 StatementResult cursor = session.run( "MATCH (n) WHERE n.name = {myNameParam} RETURN (n)",
                                       parameters );
 
 

Parameters:

statementTemplate - text of a Neo4j statement

statementParameters - input data for the statement

Returns:

a stream of result values and associated metadata

run

StatementResult run(String statementTemplate,
                  Record statementParameters)

Run a statement and return a result stream. This method takes a set of parameters that will be injected into the statement 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 statement as input for another.

Parameters:

statementTemplate - text of a Neo4j statement

statementParameters - input data for the statement

Returns:

a stream of result values and associated metadata

run

StatementResult run(String statementTemplate)

Run a statement and return a result stream.

Parameters:

statementTemplate - text of a Neo4j statement

Returns:

a stream of result values and associated metadata

run

StatementResult run(Statement statement)

Run a statement and return a result stream.

Example

 Statement statement = new Statement( "MATCH (n) WHERE n.name={myNameParam} RETURN n.age" );
 StatementResult cursor = session.run( statement.withParameters( Values.parameters( "myNameParam", "Bob" )  ) );
 
 

Parameters:

statement - a Neo4j statement

Returns:

a stream of result values and associated metadata

typeSystem

@Experimental
org.neo4j.driver.v1.types.TypeSystem typeSystem()

Returns:

type system used by this statement runner for classifying values