This is the main documentation for the gora-mongodb module. gora-mongodb module enables MongoDB backend support for Gora.

This module has been tested with MongoDB Server 2.4.x and 2.6.x series. It will connect to remote MongoDB server(s) using standard Java MongoDB Driver


Here is a following sample gora.properties file to enable MongoStore:

# MongoDBStore properties

Description of supported properties:

Property Example value Required ? Description
gora.datastore.default org.apache.gora.mongodb.store.MongoStore Yes Implementation of the persistent Java storage class for MongoDB
gora.mongodb.override_hadoop_configuration false No If true, it will allow properties to be overriden by configuration coming from Hadoop
gora.mongodb.mapping.file /gora-mongodb-mapping.xml No The XML mapping file to be used. If no value is used this defaults to gora-mongodb-mapping.xml
gora.mongodb.servers localhost:27017 Yes This value should specify the host:port for a running MongoDB node. Multiple values have to be separated by a coma character.
gora.mongodb.db mytestdatabase Yes This value should specify the database for storage of documents.
gora.mongodb.login login No Login that will be used to authenticate against MongoDB server. If blank, driver won't try authentication.
gora.mongodb.secret password No Secret that will be used to authenticate against MongoDB server.

Gora MongoDB mappings

You should then create a gora-mongodb-mapping.xml which will describe how you want to store each of your Gora persistent objects:


    <class name="org.apache.gora.examples.generated.Employee" keyClass="java.lang.String" document="employees">
        <field name="name" docfield="name" type="string"/>
        <field name="dateOfBirth" docfield="dateOfBirth" type="int64"/>
        <field name="ssn" docfield="ssn" type="string"/>
        <field name="salary" docfield="salary" type="int32"/>
        <field name="boss" docfield="boss" type="document"/>
        <field name="webpage" docfield="webpage" type="document"/>


Each class element specifying persistent fields which values should map to. This element contains;

  1. a parameter containing the Persistent class name e.g. org.apache.gora.examples.generated.Employee,

  2. a parameter containing the keyClass e.g. java.lang.String which specifies the keys which map to the field values,

  3. a parameter containing the MongoDB collection e.g. employees which will be used to persist each Gora object,

  4. finally a child element(s) field which represent all fields which are to be persisted into MongoDB. These need to be configured such that they receive the following;

    a name attribute e.g. (name, dateOfBirth, ssn and salary respectively) which map to Gora field name,

    a docfield attribute containing the field's name in mapped Mongo document,

    a type attribute which allow transformation of Gora types into native MongoDB types. MongoDB use BSON is a binary serialization format to store documents and make remote procedure calls.

    Description of supported type values:

Type value Description
BINARY Store as binary data
BOOLEAN Store as boolean value
INT32 Store as signed 32-bit integer
INT64 Store as signed 64-bit integer
DOUBLE Store as floating point
STRING Store as UTF-8 string
DATE Store as UTC datetime (ISODate)
LIST Store as Array
DOCUMENT Store as embedded document
OBJECTID Store as ObjectId (12-byte)