object-hbase-mapping

An object-to-hbase mapper (like ORM is for SQL databases). Writes (and reads) an object's fields as qualifiers in a given table, using a given column family. Persistence layer based on node-thrift2-hbase.

Usage

const nodeThriftHbase = require('node-thrift2-hbase')(thriftHBaseConfig);
const ObjectHBaseMapping = require('object-habase-mapping');

const table = 'object_hbase_mapping:example_table';
const columnFamily = 'cf';
const fieldMetaData = [
    {modelName: 'm1', hbaseName: 'u1', type: 'string', isKeyProperty: true},
    {modelName: 'm2', hbaseName: 'u2', type: 'integer', isKeyProperty: true},
    {modelName: 'm3', hbaseName: 'u3', type: 'integer'},
];

const ModelClass = ObjectHBaseMapping(nodeThriftHbase, table, columnFamily, fieldMetadata)

• hbase - an instance of node-thrift2-hbase
• table - the name of the table in which this object is stored
• columnFamily - the name of the column family in which this object is stored
• fieldMetadata is a list of objects with the following properties:
  • modelName - name of the field in the object class (i.e. instanceOfMyClass[modelName] will hold this fields's value).
  • hbaseName - the qualifier name used in HBase to store this property, (i.e. this property will be stored in columnFamily in the qualifier hbaseName).
  • type - the type of the property's value, for serialization/deserialization purposes, as in node-thrift2-hbase.
  • isKeyProperty - boolean, set to true if this property is part of the row's key.

Rowkey construction: The row key is constructed by calling the static method genKeyProperties with the object data (see static methods below).

HBaseModel

All HBase model classes created by this library extend a base class which supplies them with the following methods:

static methods

• genKeyByProperties(): .join('.')s the values of properties marked isKeyProperty by their order of appearance in fieldMetadata to generate an HBase row key.

instance methods

• save(): saves this object to HBase using the generated repository backend.
• load(): load the object from HBase using this object as a prototype query.