public interface StatementRunner
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 from the network.
This means that when any of 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:
StatementResult.next() or StatementResult.consume() Transaction.close() 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 close the session you used 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.
Session,
Transaction| 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.
|
StatementResult run(String statementTemplate, Value parameters)
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.
StatementResult cursor = session.run( "MATCH (n) WHERE n.name = {myNameParam} RETURN (n)",
Values.parameters( "myNameParam", "Bob" ) );
statementTemplate - text of a Neo4j statementparameters - input parameters, should be a map Value, see Values.parameters(Object...).StatementResult run(String statementTemplate, Map<String,Object> statementParameters)
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.
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 );
statementTemplate - text of a Neo4j statementstatementParameters - input data for the statementStatementResult run(String statementTemplate, Record statementParameters)
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.
statementTemplate - text of a Neo4j statementstatementParameters - input data for the statementStatementResult run(String statementTemplate)
statementTemplate - text of a Neo4j statementStatementResult run(Statement statement)
Statement statement = new Statement( "MATCH (n) WHERE n.name=$myNameParam RETURN n.age" );
StatementResult cursor = session.run( statement.withParameters( Values.parameters( "myNameParam", "Bob" ) ) );
statement - a Neo4j statementCopyright © 2019. All rights reserved.