我是 OrientDB 的新手。由于我是一名 Java 开发人员,因此我选择了 Graph API 作为 OrientDB 的连接器。
在这里,我创建了一个非常简单的代码示例:
package launcher;
import com.tinkerpop.blueprints.Graph;
import com.tinkerpop.blueprints.Vertex;
import com.tinkerpop.blueprints.impls.orient.OrientGraphNoTx;
import com.tinkerpop.frames.FramedGraph;
import com.tinkerpop.frames.FramedGraphFactory;
public class TinkerpopTest {
public static void main(String[] args) {
OrientGraphNoTx graph = new OrientGraphNoTx("memory:tinkerpop");
FramedGraphFactory factory = new FramedGraphFactory();
FramedGraph<Graph> manager = factory.create(graph);
Vertex marko = graph.addVertex("class:Person");
marko.setProperty("name", "marko");
marko.setProperty("age", 29);
Vertex vadas = graph.addVertex("class:Person");
vadas.setProperty("name", "vadas");
vadas.setProperty("age", 27);
Vertex lop = graph.addVertex("class:Person");
lop.setProperty("name", "lop");
lop.setProperty("lang", "java");
Vertex josh = graph.addVertex("class:Person");
josh.setProperty("name", "josh");
josh.setProperty("age", 32);
Vertex ripple = graph.addVertex("class:Person");
ripple.setProperty("name", "ripple");
ripple.setProperty("lang", "java");
Vertex peter = graph.addVertex("class:Person");
peter.setProperty("name", "peter");
peter.setProperty("age", 35);
graph.addEdge("class:Person", marko, vadas, "knows").setProperty("weight", 0.5f);
graph.addEdge("class:Person", marko, josh, "knows").setProperty("weight", 1.0f);
graph.addEdge("class:Person", marko, lop, "created").setProperty("weight", 0.4f);
graph.addEdge("class:Person", josh, ripple, "created")
.setProperty("weight", 1.0f);
graph.addEdge("class:Person", josh, lop, "created").setProperty("weight", 0.4f);
graph.addEdge("class:Person", peter, lop, "created").setProperty("weight", 0.2f);
}
}
和人类:
package launcher;
import com.tinkerpop.frames.Adjacency;
import com.tinkerpop.frames.Property;
public interface Person {
@Property("name")
String getName();
@Property("name")
void setName(String name);
@Property("age")
int getAge();
@Property("age")
void setAge(int age);
@Adjacency(label = "knows")
Iterable<Person> getKnowsPeople();
@Adjacency(label = "knows")
void addKnowsPerson(Person person);
}
我正在使用 Maven 构建我的应用程序,这里是项目依赖项:
<dependencies>
<dependency>
<groupId>com.orientechnologies</groupId>
<artifactId>orientdb-core</artifactId>
<version>3.0.1</version>
</dependency>
<dependency>
<groupId>com.orientechnologies</groupId>
<artifactId>orientdb-graphdb</artifactId>
<version>3.0.1</version>
</dependency>
<dependency>
<groupId>com.orientechnologies</groupId>
<artifactId>orientdb-object</artifactId>
<version>3.0.1</version>
</dependency>
<dependency>
<groupId>com.tinkerpop.blueprints</groupId>
<artifactId>blueprints-core</artifactId>
<version>2.6.0</version>
</dependency>
<dependency>
<groupId>com.tinkerpop</groupId>
<artifactId>frames</artifactId>
<version>2.6.0</version>
</dependency>
</dependencies>
此代码示例来自 tinkerpop 源代码。正如你所看到的,我们这里有“人”的顶点类型和某种边缘,如“知道”和“创建”。现在我发现了如何创建顶点和边以及如何向它们添加元素。但问题是我不知道根据边从图中检索元素。我知道如何通过年龄等属性检索数据,但问题是我不明白如何根据边缘检索数据。例如,如何通过 Graph API(Tinkerpop Blueprints)从上面显示的示例中找到一个不“知道”任何人的顶点?