Copyright ©2007 XBRL International Inc., All Rights Reserved.
Circulation of this Public Working Draft is unrestricted. This document is normative. Other documents may supersede this document. Recipients are invited to submit comments to the authors and contributors, and to submit notification of any relevant patent rights of which they are aware and to provide supporting documentation.
This specification is an extension to the XBRL Validations Specification [VALIDATION]. It specifies the syntax for assertions that test the number of evaluations of a given set of variables. This kind of assertion supports checking the existence of facts that meet certain conditions.
1 Introduction
1.1 Background
1.2 Relationship to other work
1.3 Language independence
1.4 Terminology
1.5 Document conventions (non-normative)
1.6 Namespaces and namespace prefixes
1.7 XPath usage
2 Syntax
2.1 Existence assertions
2.2 Existence assertions relationships
3 Test implied by existence assertions
4 The processing model for existence assertions
A Normative schema
B References
C Intellectual property status (non-normative)
D Acknowledgements (non-normative)
E Document history (non-normative)
F Errata corrections in this document
1 Namespaces and namespace prefixes
1 Existence assertions
2 Explicit dimension filters
existence assertion
existence-assertion expression
rfc2119 terminology
One of the most basic requirements in business reporting, where the consumer of the information imposes a set of rules that the provider must meet (e.g.: the reporting of financial statements from a subsidiary to its holding company), is the establishment of sets of mandatory data. This specification defines the syntax for assertions about the facts that are expected to be present or absent in an XBRL instance.
This document extends the XBRL Validations specification [VALIDATION] ,introducing a new kind of assertion that tests the number of evaluations of a given variable set.
This kind of assertion has a similar structure to the one defined by
the Value Assertion Specification [VALUE ASSERTIONS].
The main difference is that the context item of the XPath expression in the
@test
attribute is a numeric value that represents the number
of
evaluations of the set of variables determined by the assertion.
The result of the assertion is the effective boolean value of the evaluation of the XPath expression in the test attribute.
This kind of assertion facilitates the definition of business rules that perform checks like those set out in Example 1.
Many of the syntax constraints imposed by this specification are set out in the normative schema Appendix A . To eliminate the potential for conflicts, this specification only enunciates syntax features that are not expressed in the normative schema.
This specification is a member of a suite of similar specifications that define specific types of tests that can be applied to the information contained on XBRL reports.
This specification builds on the foundation provided by the XBRL Validation Specification [VALIDATION] .
The official language of XBRL International's own work products is English and the preferred spelling convention is UK English.
This specification is consistent with the definitions of any of the terms defined in specifications that it depends on.
The key words MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD, SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, in this specification, are to be interpreted as described in [IETF RFC 2119].
Documentation conventions follow those set out in the XBRL Variables Specification [VARIABLES].
Namespace prefixes [XML NAMES] will be used
for elements and attributes in
the form ns:name
where ns
is the
namespace prefix and name
is the local name.
Throughout this specification, the mappings
from namespace prefixes to actual namespaces is consistent
with
Table 1.
The prefix column in Table 1 is non normative. The namespace URI column is normative.
Prefix | Namespace URI |
---|---|
validation
|
http://xbrl.org/2007/validation
|
ea
|
http://xbrl.org/2007/assertion/existence
|
xbrleae
|
http://xbrl.org/2007/assertion/existence/error
|
eg
|
http://example.com/
|
fn
|
http://www.w3.org/2006/xpath-functions
|
link
|
http://www.xbrl.org/2003/linkbase
|
xbrli
|
http://www.xbrl.org/2003/instance
|
xfi
|
http://www.xbrl.org/2005/function/instance
|
xbrldi
|
http://xbrl.org/2006/xbrldi
|
xbrldt
|
http://xbrl.org/2005/xbrldt
|
xl
|
http://www.xbrl.org/2003/XLink
|
xlink
|
http://www.w3.org/1999/xlink
|
xs
|
http://www.w3.org/2001/XMLSchema
|
xsi
|
http://www.w3.org/2001/XMLSchema-instance
|
generic
|
http://xbrl.org/2007/generic
|
variable
|
http://xbrl.org/2007/variable
|
iso4217
|
http://www.xbrl.org/2003/iso4217
|
This specification only provides a textual declaration of syntax constraints when those constraints are not expressed by the normative schema supplied with this specification.
Explanations of elements and attributes are only supplied when explanations are not already provided in other specifications.
Unless explicitly stated otherwise, a reference to a specific element MUST be read as a reference to that element or to any element in its substitution group .
An existence assertion is expressed by the
<ea:existence-assertion>
element
in the normative schema supplied with
this specification.
The optional @test
attribute of an existence assertion
contains an XPath expression. It's content is referred to as a
existence-assertion expression.
If the @test
attribute is not provided, then the
existence expression is equal to the
context item expression.
The assertion expression MAY have variable dependencies to parameters in the variable-set, but MUST NOT have dependencies to general or fact variables.
[Error: Error code xbrleae:variableReferenceNotAllowed MUST be thrown if the assertion expression to be evaluated has a variable dependency to a general or a fact variable. ]
The following relationships defined in the Variables Specification [VARIABLES] MAY be used with existence assertions:
An existence assertion MUST be associated to at least one fact variable.
[Error: Error code xbrleae:emptyVariableSet MUST be thrown if the variable-set of the existence assertion doesn't include any fact variable. ]
An existence assertion test is the effective Boolean value of the evaluation of its assertion expression. The context for this expression MUST:
@test value |
Number evaluations of the variable set for the assertion being verified |
---|---|
.
|
At least one evaluation |
. gt 5
|
At least six evaluations |
. eq 0
|
No evaluations |
. ge $numberOfItems
|
Equal to or greater than the number provided in the parameter identified by the variable name $numberOfItems |
Existence assertions MAY produce only one evaluation for a given input, as the test implied is related to the total number of evaluations of the variable set of the assertion as a whole. Thus, the data set of an existence assertion is the whole input XBRL report.
The prerequisite for the evaluation of this kind of assertions is the evaluation of all possible different evaluations of its variable set.
The following is the XML schema provided as part of this specification. This is normative. Non-normative versions (which should be identical to these except for appropriate comments indicating their non-normative status) are also provided as separate files for convenience of users of the specification.
NOTE: (non-normative) Following the schema maintenance policy of XBRL International, it is the intent (but is not guaranteed) that the location of non-normative versions of these schemas on the web will be as follows:
http://www.xbrl.org/2007/
- during the drafting process for
this specification this directory should contain a copy of the
most recent published version of the schema at
http://www.xbrl.org/2007/existence-assertion.xsd.
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This document could not have been written without the contributions of many people including the participants in the Formula Working Group.
Date | Author | Details |
---|---|---|
30 June 2007 | Geoff Shuetrim |
Initial draft created. |
22 July 2007 | Geoff Shuetrim |
Converted to XML format. |
15 October 2007 | Geoff Shuetrim |
Adapted to XBRLspec syntax. |
24 November 2007 | Victor Morilla |
Split from validation report specification Adapted to reuse variable sets and preconditions |
26 November 2007 | Geoff Shuetrim |
Minor wording edits. |
30 November 2007 | Victor Morilla |
Adapted to new version of variables specification. Included section for processing model and added errors. |
04 December 2007 | Geoff Shuetrim |
Reworded some paragraphs. Moved some definitions to the variable specification relating to identical and different variable-set evaluations. |
04 December 2007 | Victor Morilla |
Removed agreed comments and paragraph about the consideration of preconditions and groupfilters as suggested by Geoff |
06 December 2007 | Victor Morilla |
References to the definition of the assertion data set |
16 December 2007 | Victor Morilla |
Changed namespace of existence assertions from http://xbrl.org/2007/existence-assertion to http://xbrl.org/2007/assertion/existence |
This appendix contains a list of the errata that have been incorporated into this document. This represents all those errata corrections that have been approved by the XBRL International Formula Working Group up to and including 31 December 2007. Hyperlinks to relevant e-mail threads may only be followed by those who have access to the relevant mailing lists. Access to internal XBRL mailing lists is restricted to members of XBRL International Inc.
No errata have been incorporated into this document.