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Census Hub Project NSI – Bulgaria. National Case Study. The eCensus – Incredible success!. REPUBLIC OF BULGARIA. The first EU Member State, which conducted its population count in 2011 (1-28 February). Incredible success – more than 41% enumerated via Internet!.
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Census Hub Project NSI – Bulgaria National Case Study
The eCensus – Incredible success! REPUBLIC OF BULGARIA The first EU Member State, which conducted its population count in 2011 (1-28 February). Incredible success – more than 41% enumerated via Internet! For the first time - eCensus via Internet was held from 1st to 9th February 2011. On average 300 000 citizens were enumerated a day and in the last day - more than half a million!
eCensusArchitecture • All servers are based on Windows Server 2008 R2 x64 Enterprise Edition. • The database software is Microsoft SQL Server 2008 R2 Enterprise Edition.
Technologiesused for the Census2011 • Microsoft Windows 2008 R2 Standard Edition; • Microsoft SQL Server 2008 R2 Enterprise Edition; • Microsoft Internet Information Server 7.5; • Microsoft .NET Framework 4.0; • Microsoft Visual Studio 2010; • Microsoft C# 4.0; • Microsoft ASP.NET MVC 2.0; • Microsoft Hyper-V.
The Census Hub Project IN REPUBLIC OF BULGARIA The Hub is based on 60 Hypercubes, regulated by the EU program for 2011 Census data. The Hypercubes are stored in the national Dissemination Databases and are derived when a user wants them. A modern and innovative technical solution for the transmission and dissemination of 2011 Census data of European countries via the Eurostat website in accordance with the European Commission Regulation A conceptually new system based on the concept of data sharing, where a group of partners agree on providing access to their data according to standard processes, formats and technology. For this purpose, SDMX standards for extraction, processing and exchanging data and metadata are used.
BEFORE THE START of Census Hub Project: • We hadalready conducted our 2011 Census. • 8 cubes were designed and loaded by transformations of Census data from Operational to the Analytical DB using MS SQL Server Analysis Services. (MsOlap cubes). • Dwellings cube; • Buildings cube; • Collective Households cube; • Families cube; • Households cube; • Population cube; • Total Dwellings cube (including uninhabited ones); • Total Population cube (including temporarily residing).
BEFORE THE START of Census Hub Project (2): • We analysed the possibility to use part of the existing hardware and software intended for the Census 2011. Hardware – 2 machines • A Windows Server 2008 machine acting both as WEB Application server and Database server. • A Database server machine containing the Census 2011 data – the Operational Database and the Analitycal (OLAP) Database with the 8 cubes , mentioned above. Software
The European Census Hub Project in NSI Bulgaria The national implementation • The purpose of the project • The development of a web service which is compatible with the CENSUS HUB WEB application and which would process the SDMX queries received from Eurostat. • Two possible approaches to achieve the Census Hub objective: • To develop our own SDMX Reference Infrastructure; • To use already developed SDMX Infrastructure. • Choosing this aproach, we had 2 possibilities: • SDMX NSI Reference Infrastructure, developed by Eurostat; • SDMX ISTAT Framework, developed by Statistics Italy.
Additional software installed for the SDMX RI • Our decision: • After reading the Eurostat documentation, published on Circa, our decision was to install the SDMX NSI Reference Infrastructure, developed by Eurostat. • Regarding the data, our decision was to use Eurostat’s approach with the Mapping Store Database. This was the way to be sure all data would be in the format expected by Eurostat. We downloaded from Circa and installed on the WEB Application server : • NSI Web Service v 2.1.5; • Mapping Assistant v 2.6.0; • Test Client v 2.1.6. to test the whole setup at the end.
CHALLENGES in The Census Hub Project implementation • To choose the right approach concerning the SDMX Refference Architecture in BNSI • We took the right decision choosing the SDMX NSI Reference Infrastructure, developed by Eurostat. • Issues associated with performance, security and other constrains, related with IT • To provide the security, Cisco ASA 5540 was used, where separated demilitarized zones (DMZ) for the application servers and database servers are configured. • A server certificate has been generated and submitted to Eurostat for allowing the connection with the WS.
WEB Service Description • Developed as a module of the Census 2011 Information system. • Through the process of WS building, all the recommendations of Eurostat on the architecture and functionality have been met. • The purpose of the WS is to retrieve the necessary data from the Dissemination Database (DDB), using mappings between DSD, and DDB, stored in the Mapping Store Database. • We installed the WS on the WEB Application server and registered it in IIS under the name CensusHub. • A server certificate has been generated and submitted to Eurostat for allowing the connection with the WS. • The certificate has been assigned to the website censushub.nsi.bg using IIS. • SSL bindings have been configured in IIS. • The site has also been configured to use Basic HTTP Authentication.
Databases Description • All the Databases (the Mapping Store Database, the Dissemination Database (DDB) and the OLAP Database) are installed on one machine with MS SQL Server 2008 R2 Enterprise Edition. • The Mapping Store Database is generated and supported by Mapping Assistant. • It keepsthe mappingsbetweenthe SDMX componentsand the DDB. • The WS uses this information toretrievefrom the DDB the data, required by the SDMX-ML Query, and transform itto anSDMX-ML message. • The DDB is the local data storage of the NSI dissemination environment . • We chose to generate the DDB, using the most simple schema (TYPE A) and the same structure for the tables with the hypercubes, recommended by Eurostat. • Currently our DDB contains only one table (H06) – the table, corresponding to HyperCube 6 according to the Eurostat specifications.
Databases Description(2) Structure of HC06 table from DDB (The same as in the Eurostat specifications) The 8 structural dimensionsdefined by legislation (from GEO to AGE) The attributes, defined at the CELL (OBS_VALUE, OBS_STATUS, OBS_LEVEL) and at the GROUP level (TIME, TIME_FORMAT, FREQ)
Databases Description(3) • The OLAP Database contains cubes and dimensions, generated and fed with data from the Census 2011 for the needs of NSI. • We used the OLAP Database as a source for populating the DDB. • The OLAP Database contains all the data that has to be extracted, transformed and loaded into the DDB. • The whole ETL process is done through a combination of SQL and MDX scripts. • The result from the MDX scripts is then loaded into the DDB.
Data Collection and Mapping DDB Connected as a Linked Server SQL script, executing the MDX Scripts against the OLAP Database Writing to the DDB table Collecting Data • Before running the scripts, the OLAP Database has to be connected to the Relational Database as a Linked Server. • Mapping of dimensions between the OLAP database and the Eurostat DSDs is done through declarations of calculated members in the MDX script. • There is a separate MDX query for each sub-cube of the Hypercube, containing the calculated member declarations and a cross-join for getting the Cartesian product of aggregated data over the members of the included dimensions.
Data Collection and Mapping (2) DDB Connected as a Linked Server SQL script, executing the MDX Scripts against the OLAP Database Writing to the DDB table Collecting Data • The SQL script executes the queries from the MDX scripts against the Linked Server. • The results from the MDX script are saved into a temporary table variable. • Some additional modifications are done. • At the end the data are loaded into the DDB table.
At the end of August 2011, we were ready to send to Eurostat all the necessary information for testing our WEB Service: • the URL; • the certificate for authorization; • the User name and Password for the certificate and for the Basic HTTP Authentication user on the Web server. • Soon after that, we were happy to be welcomedon board for the Census Hub project with an official letter from Eurostat. • Our participation in the Census Hub project was a very good occasion to gain experience from such a modern and innovative technical solution and to start using SDMX formats.
THANK YOU FOR YOUR ATTENTION! Plamen Minkov, Director of Information and Communication Technology Department, NSI, BULGARIA. Tel. 00359 2 9857 528 E-mail: pminkov@nsi.bg