Package com.hazelcast.sql

Interface SqlService

public interface SqlService
A service to execute SQL statements.

In order to use the service, Jet engine must be enabled - SQL statements are executed as Jet jobs. On members, the hazelcast-sql.jar must be on the classpath, otherwise an exception will be thrown; on client, it is not necessary.

Overview

Hazelcast is currently able to execute distributed SQL queries using the following connectors:
  • IMap
  • Kafka
  • Files
When an SQL statement is submitted to a member, it is parsed and optimized by the hazelcast-sql module, that is based on Apache Calcite. During optimization a statement is converted into a directed acyclic graph (DAG) that is sent to cluster members for execution. Results are sent back to the originating member asynchronously and returned to the user via SqlResult.

SQL statements are not atomic. INSERT/SINK can fail and commit part of the data.

Usage

Before you can access any object using SQL, a mapping has to be created. See the reference manual for the CREATE MAPPING command.

When a query is executed, an SqlResult is returned. You may get row iterator from the result. The result must be closed at the end. The code snippet below demonstrates a typical usage pattern: 

     HazelcastInstance instance = ...;

     try (SqlResult result = instance.sql().execute("SELECT * FROM person")) {
         for (SqlRow row : result) {
             long personId = row.getObject("personId");
             String name = row.getObject("name");
             ...
         }
     }

  • Method Summary

    Modifier and Type
    Method
    Description
    SqlResult
    execute(SqlStatement statement)
    Executes an SQL statement.
    default SqlResult
    execute(String sql, Object... arguments)
    Convenient method to execute a distributed query with the given parameter values.
    default long
    executeUpdate(String sql, Object... arguments)
    Convenience method to execute a distributed non-DQL statement (that is a statement that does not return rows) with the given parameter values.