公开分布式高性能查询的源代码和部署方案.(二）

5）创建复杂的对象关联，在Versant数据库中也非常容易，可以直接理解为内存对象的操作。

public void createKnownPerson() {

TransSession session = DistributedDatabaseManager.getInstance()

.createNewSession();

session.setDefaultDatabase("dbnodeb");

Person personA = new Person();

personA.setFirstName("AAF1");

personA.setLastName("AAL1");

Person personB = new Person();

personB.setFirstName("BBF1");

personB.setLastName("BBL1");

personB.addFriend(personA);

Person personC = new Person();

personC.setFirstName("CCF1");

personC.setLastName("CCL1");

personC.addFriend(personB);

Person personD = new Person();

personD.setFirstName("DDF1");

personD.setLastName("DDL1");

personD.addFriend(personC);

session.makePersistent(personA, "dbnodea");

session.makePersistent(personB, "dbnodeb");

session.makePersistent(personC, "dbnodea");

session.makePersistent(personD, "dbnodeb");

System.out.println("Special Test Data created.");

session.commit();

}


6）Versant数据库的对象查询

Versant数据库可以支持SQL查询和NOSQL查询两种模式，以下为SQL查询的例子：

TransSession session = DistributedDatabaseManager.getInstance()

.createNewSession();

VQLQuery q = new VQLQuery(

session,

DistributedDatabaseManager.getInstance().HPC_DEMO_NETWORK_NAME,

"select selfoid from com.versant.domain.Person where firstName='AAF1' and lastName='AAL1'");

//"select * from com.versant.domain.Person");

System.out.println("About to execute query, and load root object.");

VEnumeration results = q.execute();

// 创建已经走过的朋友路径，避免回环

System.out

.println("--------------------------------------------------------------------------");