Kundera with Couchbase

This is an experimental feature. We encourage the community to contribute to the development and testing of it.

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Apache Couchbase

Couchbase Server is an open source, distributed, NoSQL document-oriented database. It exposes a fast key-value store with managed cache for submillisecond data operations, purpose-built indexers for fast queries and a query engine for executing SQL-like queries.

Support

Being a JPA provider, Kundera provides support for Couchbase.

Mapping

Records from all the tables of a database will be stored in a couchbase bucket.

Java Object	Couchbase
Database	Bucket
Table	No separate entity
Columns	Keys of document
Object	Document

Lets understand with an example.

Consider this Person entity in TEST_DB database.

@Entity
public class Person
{
   @Id
   private String id;

   @Column
   private String name;

   @Column
   private int age;

  // setters and getters. 
}

Sample Java object

Person person = new Person();
person.setId("101");
person.setName("Dev");
person.setAge(25);

Corresponding Couchbase document

{
  "id": "101",
  "name": "Dev",
  "age": 25,
  "kundera_enity": "Person"
}

with primary key person_101 in TEST_DB bucket.

Did you observe an extra key kundera_enity?

This key is used while JPA querying.

For example, this JPA query

select p from Person p where p.age >= 30

will get converted into

select * from couchbase_db where kundera_enity = 'Person' AND age > 30

Dependency

To use it, user needs to add the following dependency in pom.xml:

<dependency>
     <groupId>com.impetus.kundera.client</groupId>
     <artifactId>kundera-couchbase</artifactId>
     <version>${kundera.version}</version>
</dependency>

Persistence unit configuration

<persistence-unit name="couchbase_pu">
	<provider>com.impetus.kundera.KunderaPersistence</provider>
	<class>com.impetus.client.couchbase.entities.Person</class>
	<exclude-unlisted-classes>true</exclude-unlisted-classes>
	<properties>
		<property name="kundera.nodes" value="localhost" />
		<property name="kundera.client" value="couchbase" />
		<property name="kundera.keyspace" value="test_db" />
		<property name="kundera.username" value="admin" />
		<property name="kundera.password" value="password" />
		<property name="kundera.ddl.auto.prepare" value="update" />
		<property name="kundera.client.lookup.class"
			value="com.impetus.client.couchbase.CouchbaseClientFactory" />
		<property name="kundera.client.property" value="kunderaCouchbaseTest.xml" />
	</properties>
</persistence-unit>

kundera.username and kundera.password are credentials for cluster-wide operations.

Features:

• CRUD

  • User can Create, Read, Update and Delete data in Couchbase Buckets using Kundera. Refer test-case.

• Basic Select Queries

  • User can perform basic SELECT queries with WHERE clause. Refer test-case.

• Native Queries

  • Native queries can also be performed using entityManager.createNativeQuery() method. Refer test-case.

• Schema Generation

  • User can automatically generate schema by using kundera.ddl.auto.prepare property in Persistence Unit. Check Schema Generation for more details.

Limitations:

• CRUD on simple entities (without embeddables, relationships and inheritance) is possible.
• Only queries with WHERE clause are allowed.

ToDo:

• Externalize different ports and timeouts.
• Support secondary indexes.