Using Java to Operate ObjectivityDB
ObjectivityDB is a high-performance Object database. The following are the steps to operate ObjectivityDB using Java:
1. Introduce Maven dependency (the latest version of ObjectivityDB is 16.1.2):
<dependency>
<groupId>com.objy.db</groupId>
<artifactId>objy</artifactId>
<version>16.1.2</version>
</dependency>
2. Create a database connection for ObjectivityDB and obtain the Database object:
import com.objy.db.*;
public class ObjectivityDBDemo {
public static void main(String[] args) {
//Connect to database
Db.open("databaseName");
//Get Database Objects
Database database = Db.getInstance().getDatabase("databaseName");
}
}
Here, you need to replace 'databaseName' with the name of the database you want to connect to.
3. Create and define object classes:
import com.objy.db.app.*;
import com.objy.db.util.*;
public class Person extends Oid {
private String name;
private int age;
public Person(String name, int age) {
super();
this.name = name;
this.age = age;
}
//Add getters and setter methods
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
}
4. Examples of data insertion, modification, query, and deletion:
//Creating Objects
Person person = new Person("John Doe", 30);
//Create the object in the database
database.makePersistent(person);
//Modify the properties of an object
person.setName("Jane Smith");
//Update the data of objects in the database
database.update();
This will create a Person object named "John Doe" with an age of 30 and insert it into the database. Then, the name of the object will be changed to "Jane Smith" and updated to the database.
//Query Object
OSet resultSet = database.queryByExample(Person.class);
//Traverse query results
while (resultSet.hasNext()) {
Person p = (Person) resultSet.next();
System.out.println("Name: " + p.getName() + ", Age: " + p.getAge());
}
This will query all Person type objects in the database and print out the name and age of each object.
//Delete Object
database.delete(person);
//Update Database
database.update();
This will delete the previously created Person object from the database and update the database.
Precautions:
-Introduce ObjectivityDB dependencies and set the correct version number.
-Change the database name according to the actual situation.
-The Inner class Person needs to inherit the Oid class and add getter and setter methods.
-After using the database object, the 'database. update()' method needs to be called to persist the updates to the database.
