Data Access and Storage Facilities

Accessing data sources for retrieval or storage purposes is a fundamental requirement for a wide range of system processes, including indexing, transfer, transformation, and presentation. Equally, it is a main driver for clients that interface the resources managed by the system.

A large number of system components are dedicated to meet data access requirements, including services, service plugins, client-side libraries, server-side libraries, and front-end interfaces.

This document outlines the rationale and high-level architecture of such components.

Overview

Collectively, data access components provide three key facilities:

• the ability to store data in resources managed by the system;
• the ability to access data that is stored in resources managed by the system;
• the ability to access data that is stored in resources managed externally to the system;

The facilities are provided over data with heterogeneous structure, size, and semantics:

• from unstructured data to structured data and semi-structured data;
• from small data sets to large and very large data sets;
• from document data, to statistical, biodiversity, and semantic data;

and in compliance with the following non-functional requirements:

• the requirement of secure access;
• the requirement of scalable and efficient access;
• the requirement of standards-based access;

In summary, the data access components provide secure, scalable, efficient, standards-based storage and retrieval of data, where the data may be maintained by the system or outside the system and may vary in structure, size, and semantics.

Key Features

uniform model and access API over structured data

dynamically pluggable architecture of transformations to and from internal and external data sources;

standards-based plugins for document, biodiversity, statistical, and semantic data sources;

fine-grained access to structured data

horizontal and vertical filtering based on pattern matching;

URI-based resolution;

in-place remote updates;

scalable access to structured data

autonomic service replication with infrastructure-wide load balancing;

efficient and scalable storage of structured data

based on graph database technology;

rich tooling for client and plugin development

high-level Java APIs for service access;

DSLs for pattern construction and stream manipulations;

TODO features for biodiversity data

Lucio please add with respect Species Service

TODO features for file access and storage

Roberto please add with respect to File Storage API

Subsystems

Data access components cluster within the following subsystems:

the Tree-Based Data Access subsystem

groups components that implement access and storage facilities for structured data of arbitrary semantics, origin, and size;

the Biodiversity Data Access subsystem

groups components that implement access and storage facilities for structured data with biodiversity semantics and arbitrary origin and size;

the File-Based Access subsystem

groups components that implement access and storage facilities for unstructured data with arbitrary semantics and size;