2.1.1. XBRL structure
The taxonomy
A XBRL taxonomy [1] is a dictionary of terms built in a hierarchycal structure. The taxonomy
consists of two important parts: the schema file (or more schemas) and linkbases.
The schema file contains the elements and their characteristics such as names, ids and other
attributes. A schema file has an .xsd extension and it is an XML schema file.
The root element of all schemas is called <schema>. The starting root element is <schema>
and the ending root element is </schema>. XML documents and XBRL documents as well use
namespaces. A namespace is used to distinguish between elements of different schemas. A
namespace is like an Internet address (“http://xbrl.iasb.org/int/fr/ifrs-gp/”) but it’s not. The reason
for using such names is their uniqueness and so unique elements in the schemas can be identified.
Elements are in fact business concepts like Assets. In the following example we present a
concept named “Depreciable”. The most important parts provided in this example, from a
business perspective, are name, type, balance and PeriodType.
<element id="ci_Depreciable" name="Depreciable"
type="xbrli:monetaryItemType" substitutionGroup="xbrli:item"
xbrli:periodType="instant" xbrli:balance="debit" />
Name is a unique element assigned to the concept, type is the type of the concept (in our case
is a monetary type), PeriodType makes a distinction between flows and resources.
Payments, revenues or profit have the PeriodType duration.
XBRL has also to express the balance nature of the concept: debit or credit. The schema
document reflects the nature of the concept by using the balance attribute: balance=”debit”.
Linkbases [1] are the components of the taxonomy that provide relationship between elements
and link them with external resources.
The linkbase files are named using the name of the taxonomy followed by an underscore and
then the type of the linkbase file :”basicCalculation_labels.xml”. In this case the taxonomy file
name is basicCalculation.xsd.
The taxonomy linkbase files [1] are:
■ labels
■ references
■ presentations
■ calculations
■ definitions
The labels file [1] has the detailed description for all the elements in the taxonomy. There are
at least four entries for each element if a single language is supported:
■ locator entry
■ label entry
■ arc entry from the taxonomy to the label
■ arc entry from the label to the taxonomy
The reference file [1] points to source documents ( documents issued by the authorities)
indicating the relevant paragraphs and clauses.
The presentation file [1] is responsible for displaying the elements on the order in which it
should appear in the financial statement.
The calculation file [1] improves the quality of the XBRL report. It has definitions of
validation rules. These validation rules apply to all instance documents that refer to a specific
taxonomy.
The definition file [1] creates all the parent-child relationships.