1. SDMX: Frequently Asked Questions
Danny DELCAMBRE
Eurostat, Unit B.5 Data and metadata services; Standards
European Statistical Training Programme (ESTP) SDMX Basics course, 5-7 March 2019, Luxembourg

2. Trigger for sending data in SDMX format ?
Eurostat sends a request accompanied by guidelines describing the data exchange. All information needed to structure data based on the SDMX format should be included in this document
Use the appropriate SDMX tools depending on
your data system, and
the complexity of the domain

3. Where to find SDMX objects?
Eurostat guidelines: name, version and location of SDMX objects to be used for the data exchange
SDMX registries: for downloading these objects

4. Format versus version? Use "Format" for SDMX 2.0 or 2.1
Ex: download a DSD in SDMX format 2.0
Use "Version" for SDMX object numbers
Ex: DSD named STSALL version 2.1
It is possible to download the DSD STSALL version 2.1 in format SDMX 2.0

5. Use of SDMX 2.0 or 2.1?
The use of formats SDMX 2.0 or 2.1 for SDMX objects should be transparent
For transmission of data, the format will be specified in Eurostat guidelines. The main format used in reception at Eurostat is SDMX 2.0 COMPACT

6. Which version of the Converter?
The latest version of the tools can be downloaded from the SDMX Infospace Website
No need to upgrade an existing version of the tool when a new one is delivered (except if a problem is detected)

7. CSV header versus SDMX header?
The CSV header corresponds to the name of the columns in a CSV file
The SDMX header is the description of a data file in XML format
<Header> <ID>IREF000506</ID> <Test>false</Test> <Name>ECB structural definitions</Name> <Prepared> T14:26:00</Prepared> <Sender id="4F0"/> </Header>
For a conversion from CSV to SDMX format, both are needed

8. Use of constraints? Subset of codes allowed in a data exchange
Used for validation purposes
If needed for a data exchange, they are specified in the dataflows listed in Eurostat guidelines

9. Use a concept as a dimension or an attribute?
FREQUENCY
COUNTRY
TOURISM_ACTIVITY
TOURISM_INDICATOR
UNIT
OBS_VALUE
TIME E
OBS_STATUS P
DIMENSIONS
ATTRIBUTES
MEASURES

10. Dimension vs attribute
In some specific cases a dimension can be replaced with an attribute.
In dataset 1, “Bulgaria” and “time” are enough to uniquely identify the observations (euro is not a distinctive element), so the “currency” concept could be transformed into an attribute.
In dataset 2, the three concepts are necessary to uniquely identify observations, so the “currency” concept cannot be transformed into an attribute.
Maintaining the “currency” concept as a dimension in dataset 1 would complicate the database for no benefit.
Some concepts, such as "Observation Status" or "Confidentiality Status", will typically be attributes, as they are generally not used to uniquely identify the data

11. Use of the Converter or the SDMX-RI?
It depends on the complexity of the data exchange
NSI could choose the better solution depending on their system (unless special requirements from Eurostat)
The Converter can be used as an intermediate step because it is faster to configure.

12. Other questions? More FAQ: https://sdmx.org/?page_id=7
Not yet happy?