Kundera with Couchdb

Couchdb

Couchdb is an open source database that enables easy access of data over web. CouchDB uses JavaScript Object Notation (JSON) for data storage, a lightweight format based on a subset of JavaScript syntax. Its download and installation instructions are available at its site.

Support

Being a JPA provider, Kundera provides support for Couchdb. It allows to perform CRUD and query operation over Couchdb in jpa way. Let's look into how to use Kundera over Couchdb as database.

• Entity

*/
@Entity
public class PersonCouchDB
{

    /** The person id. */
    @Id
    @Column(name = "PERSON_ID")
    private String personId;

    /** The person name. */
    @Column(name = "PERSON_NAME")
    private String personName;

    /** The age. */
    @Column(name = "AGE")
    private Integer age;
  // setters and getters. 
}

Persistence unit configuration

 <persistence-unit name="couchdb_pu">
                <provider>com.impetus.kundera.KunderaPersistence</provider>
                <properties>
                        <property name="kundera.nodes" value="localhost" />
                        <property name="kundera.port" value="5984" />
                        <property name="kundera.keyspace" value="couchdatabase" />
                        <property name="kundera.dialect" value="couchdb" />
                        <property name="kundera.client" value="couchdb" />
                        <property name="kundera.ddl.auto.prepare" value="create" />
                        <property name="kundera.client.lookup.class"
                                value="com.impetus.client.couchdb.CouchDBClientFactory" />
                        <property name="kundera.cache.provider.class"
                                value="com.impetus.kundera.cache.ehcache.EhCacheProvider" />
                        <property name="kundera.cache.config.resource" value="/ehcache-test.xml" />
                </properties>
</persistence-unit>

CRUD

final String nodeId = "node1";
final String originalName = "vivek";
PersonCouchDB object = new PersonCouchDB();
object.setAge(32);
object.setPersonId(ROW_KEY);
object.setPersonName(originalName);
object.setDay(Day.TUESDAY);
object.setMonth(Month.JAN);

Node node = new Node(nodeId, PersonCouchDB.class, new TransientState(), null, ROW_KEY);
node.setData(object);
client.persist(node);

PersonCouchDB result = (PersonCouchDB) client.find(PersonCouchDB.class, ROW_KEY);

```
```
// Find by key and now row key
String findByIdAndAge = "Select p from PersonCouchDB p where p.personId=:personId AND p.age=:age";
query = em.createQuery(findByIdAndAge);
query.setParameter("personId", ROW_KEY);
query.setParameter("age", 32);
```

* **Range**
```
 // Find by greater than and less than clause over non row key
String findAgeByGTELTEClause = "Select p from PersonCouchDB p where p.age <=:max AND p.age>=:min";
query = em.createQuery(findAgeByGTELTEClause);
query.setParameter("min", 32);
query.setParameter("max", 35);
```

* **Between clause**
```
 // find by between over non rowkey
String findAgeByBetween = "Select p from PersonCouchDB p where p.age between :min AND :max";
query = em.createQuery(findAgeByBetween);
query.setParameter("min", 32);
query.setParameter("max", 35);
```
* Please refer [CouchDBQueryTest](https://github.com/impetus-opensource/Kundera/tree/trunk/src/kundera-couchdb/src/test/java/com/impetus/client/couchdb/query)for more details over JPA query support.

**_You may also refer [junits](https://github.com/impetus-opensource/Kundera/tree/trunk/src/kundera-couchdb/src/test/java/com/impetus/client/couchdb) for more examples._**

### To-do