SQL
The SQL service provided by Hazelcast allows you to query data stored in IMap
declaratively.
The SQL feature is currently in beta. The compatibility between versions is not guaranteed. API might change between versions without notice. |
If you’re using the hazelcast-all or hazelcast-enterprise-all packages, the hazelcast-sql
module is included in them by default. If not, i.e., you are using hazelcast or hazelcast-enterprise ,
then you need to have hazelcast-sql in the classpath.
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Example: How to Query an IMap using SQL
Consider that we have a map called emp
that contains values of type Employee
:
public class Employee implements Serializable {
private String name;
private int age;
public Employee(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
}
The following code prints names of the employees whose age is less than 30:
try (SqlResult result = hazelcastInstance.getSql().execute("SELECT name FROM emp WHERE age < ?", 30)) {
for (SqlRow row : result) {
String name = row.getObject(0);
System.out.println(name);
}
}
You can run the same code snippet from a member or a client.