In-Memory SQL Grid (IMSG)

Apache Ignite SQL Grid is a distributed data grid where you can execute ANSI SQL-99-compliant SQLs (SELECT, UPDATE, INSERT, MERGE, and DELETE queries) to manipulate a cache. The Apache Ignite cache API provides you with the get/put/remove methods (and variants) to interact with the cache, but the SQL API offers you more flexibility; for instance, you can execute a SELECT query to fetch objects or update a few specific records using a where clause, or delete objects from a cache.

 Applications developed in different languages can interact with the Ignite platform with their native APIs and ANSI SQL-99 syntax through Apache Ignite's JDBC and ODBC APIs. Suppose you want to store student information in a database table called student. In the in-memory world, you can create a student cache to store data. The student cache will store the student ID as the key and the student object as the value. If you know the student id, you can easily fetch the student details by calling cache.get(studentId). SQL grid APIs enable you to query the student using its fields—such as you can query:

 SELECT * FROM student WHERE firstName = 'john'

The student class needs to be serializable. The following is the Student class code snippet. Some fields are annotated with @QuerySqlField to make them queriable. You can write an SQL query to fetch students data with studentId, firstName, or lastName. We will cover the indexing in SQL section:

public class Student implements Serializable {
  private static final long serialVersionUID = 1L;
 @QuerySqlField(index = true)
 private Long studentId;
 @QuerySqlField(index= true)
 private String firstName;
 @QuerySqlField(index= true)
 private String lastName;
  ... 
}