Apache Ignite v2.7.5支持非共置(non-collocated)联接查询中的嵌套联接(nested join)。下面是一个包含代码示例的解决方法:
首先,确保你已经在你的项目中添加了Apache Ignite的依赖项。
创建一个IgniteCache对象,用于存储你的数据。这里我们假设你已经有两个缓存,分别是"Person"和"Order"。
IgniteConfiguration cfg = new IgniteConfiguration();
Ignite ignite = Ignition.start(cfg);
IgniteCache personCache = ignite.getOrCreateCache("Person");
IgniteCache orderCache = ignite.getOrCreateCache("Order");
public class Person {
@QuerySqlField(index = true)
private int id;
@QuerySqlField
private String name;
// Getters and setters
}
public class Order {
@QuerySqlField(index = true)
private int id;
@QuerySqlField(index = true)
private int personId;
@QuerySqlField
private String productName;
// Getters and setters
}
ignite.getOrCreateCache(new CacheConfiguration<>("Person").setIndexedTypes(Integer.class, Person.class));
ignite.getOrCreateCache(new CacheConfiguration<>("Order").setIndexedTypes(Integer.class, Order.class));
personCache.put(1, new Person(1, "John"));
personCache.put(2, new Person(2, "Jane"));
orderCache.put(1, new Order(1, 1, "Product A"));
orderCache.put(2, new Order(2, 1, "Product B"));
orderCache.put(3, new Order(3, 2, "Product C"));
SqlQuery sql = new SqlQuery<>(Person.class, "SELECT * FROM Person INNER JOIN Order ON Person.id = Order.personId");
QueryCursor> cursor = personCache.query(sql);
for (Cache.Entry entry : cursor) {
Person person = entry.getValue();
System.out.println("Person: " + person.getName());
Collection> orders = orderCache.query(new SqlQuery<>(Order.class, "SELECT * FROM Order WHERE personId = ?", person.getId())).getAll();
for (Cache.Entry orderEntry : orders) {
Order order = orderEntry.getValue();
System.out.println("Order: " + order.getProductName());
}
}
这就是在Apache Ignite v2.7.5中使用非共置联接查询执行嵌套联接的解决方法。请根据你的实际需求进行修改和适应。