4.1 IT Architecture
Statistics Finland's common metadata system is implemented according to the principles of service-based architecture.
Services meeting the needs of different user groups and client systems have a key role in the service-based architecture. The picture below shows the service interface to be built on top of the metadata warehouse, whose services produce the required data from the documents in the metadata warehouse, and also attend to storing of data to the warehouse.
The content of the metadata warehouse is maintained and it can be made available in client systems by ordering services through the service interface from the metadata warehouse. The service interface is implemented in line with the REST architecture (Representational State Transfer). The basic structures of the application are carried out according to the layer style. The business logic layer is formed of REST service interfaces, their processing logics and data transfer modules offered by the interfaces to client software. The function of data transfer modules is to offer data from the XML data warehouse to client software with an easy-to-use entity structure.
4.2 Metadata Management Tools
See Section 2.2.
4.3 Standards and formats
Statistics Finland has developed a Common Structure of Statistical Information (CoSSI) based on xml. It is a modular data model for describing statistical tables, classifications, concepts, variables, general information on statistical documents, quality descriptions, etc. CoSSI was designed in accordance with international standards such as the Dublin Core and CALS. If needed, CoSSI can be expanded; new elements, e.g. for data descriptions have already been integrated into it. In its ITC strategy, Statistics Finland has provided guidelines for the use of the CoSSI model. The data models of the classifications and concepts in use have been developed in the 1990s, and the elements they contain are presently part of CoSSI.
CoSSI documentation on the web: http://www.stat.fi/org/tut/dthemes/drafts/cossi_en.html
4.4 Version control and revisions
The versioning of the classifications can be seen as a 4-level hierarchy:
A configuration on the versioning of the classifications (see picture below).
(click on the thumbnail to view full size image)
4.5 Outsourcing versus in-house development
The user interfaces and the applications for the databases have been mainly developed and built in-house.The applications developed at Statistics Finland can in principle be shared free of charge with other statistical organizations. Where necessary, details regarding test use and access to more precise descriptions etc. may be agreed upon separately.