Copyright ©2009 XBRL International Inc., All Rights Reserved.
Circulation of this Recommendation is unrestricted. This document is normative. Recipients are invited to submit comments to formula-feedback@xbrl.org, and to submit notification of any relevant patent rights of which they are aware and provide supporting documentation.
This specification is an extension to the Validation Specification [VALIDATION]. It specifies the syntax for assertions that facilitate testing for the existence of facts meeting specified criteria. The assertions operate by testing the number of different evaluations of a given variable set that are possible for a given input XBRL instance. This makes them more flexible in terms of the kinds of data that they can test for, compared to the consistency assertions defined in the Consistency Assertions Specification [CONSISTENCY ASSERTIONS].
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 Relationships involving existence assertions
3 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 Data existence assertions
2 Existence assertion expressions
existence assertion
existence assertion test
existence-assertion expression
rfc2119 terminology
One of the most basic requirements in business reporting (e.g.: the reporting of financial statements from a subsidiary to its holding company) is for users of business reports to be able to impose rules on the producers of business reports.
This specification extends the XBRL Validation specification [VALIDATION], defining syntax for assertions about the data that must be in business reports and the data that must not be in business reports.
This assertion about the existence of data in business reports
has a similar syntactic structure to the assertion defined in
the Value Assertion Specification [VALUE ASSERTIONS].
The main difference is that the context item of the XPath expression in the
@test
attribute on the assertion is a numeric value that represents the number
of different evaluations of the
variable set,
defined by the assertion, that is expected to be possible
for an assertion input.
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 assertions that can be tested against the information contained in XBRL business 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/2008/validation
|
ea
|
http://xbrl.org/2008/assertion/existence
|
xbrleae
|
http://xbrl.org/2008/assertion/existence/error
|
eg
|
http://example.com/
|
fn
|
http://www.w3.org/2005/xpath-functions
|
link
|
http://www.xbrl.org/2003/linkbase
|
xbrli
|
http://www.xbrl.org/2003/instance
|
xfi
|
http://www.xbrl.org/2008/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
|
gen
|
http://xbrl.org/2008/generic
|
variable
|
http://xbrl.org/2008/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 a statement about the number of times that the assertion's variable set will evaluate against a input XBRL instance.
An existence assertion is expressed by the
<ea:existenceAssertion>
element in the normative schema supplied with this specification.
If an existence assertion contains a
@test
attribute,
the existence-assertion expression
is the XPath expression contained by that attribute.
If the
@test
attribute is omitted from the existence assertion,
then the existence-assertion expression is equal to the
context item expression
[
1
]
.
The assertion expression MAY have variable dependencies on parameters in the variable-set, but MUST NOT have dependencies on general variables or fact variables.
Error code xbrleae:variableReferenceNotAllowed MUST be thrown if the existence-assertion expression has a variable dependency on a general variable or a fact variable.
Existence assertions are in the
substitution group
for the
<validation:variableSetAssertion>
element, and so, can be starting resources for those relationships that are required
to have a
variable-set as starting resource.
An existence assertion test is the effective Boolean value produced by evaluating an existence assertion.
An existence assertion evaluation involves evaluation of the existence-assertion expression using an evaluation context where the context item has an atomic value equal to the cardinality of the set of all possible different evaluations of the assertion's variable-set.
In-scope variables MUST include all variable parameters associated to the assertion, but MUST NOT include any fact variable or general variable.
@test attribute value |
Number of evaluations of the variable set for the assertion being verified |
---|---|
omitted | At least one evaluation |
.
|
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 produce at most one evaluation for a given assertion input. This is because the existence assertion test 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 entire assertion input.
An existence assertion MAY be evaluated for any valid assertion input. Testing of an existence assertion requires all possible different evaluations of the assertion's variable set to be performed to determine the context item for the existence assertion expression.
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/2008/
- 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/2008/existence-assertion.xsd.
This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to XBRL International or XBRL organizations, except as required to translate it into languages other than English. Members of XBRL International agree to grant certain licenses under the XBRL International Intellectual Property Policy (www.xbrl.org/legal).
This document and the information contained herein is provided on an "AS IS" basis and XBRL INTERNATIONAL DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
The attention of users of this document is directed to the possibility that compliance with or adoption of XBRL International specifications may require use of an invention covered by patent rights. XBRL International shall not be responsible for identifying patents for which a license may be required by any XBRL International specification, or for conducting legal inquiries into the legal validity or scope of those patents that are brought to its attention. XBRL International specifications are prospective and advisory only. Prospective users are responsible for protecting themselves against liability for infringement of patents. XBRL International takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Members of XBRL International agree to grant certain licenses under the XBRL International Intellectual Property Policy (www.xbrl.org/legal).
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/2008/existence-assertion to http://xbrl.org/2008/assertion/existence |
29 January 2008 | Victor Morilla |
Removed constraint on the number of fact variables of existence assertions and its corresponding error as suggested by Herm Fischer. |
31 January 2008 | Geoff Shuetrim |
Standardised the format of the hyperlinks to the normative schema. Standardised the boilerplate text for errata. |
04 February 2008 | Geoff Shuetrim |
Corrected the element name for the existence assertion in the text of the specification. Corrected the caption for the first example. It used to refer to dimension filters instead of existence assertion expressions. |
06 February 2008 | Victor Morilla |
Editorial changes suggested by Geoff Shuetrim. Merged "test implied" and "processing model" chapters. Clarified in-scope variables of the existence assertion expression. Simplified redundant paragraph about variable-set relationships. |
13 March 2008 | Geoff Shuetrim |
Added mention of the limited ability to use consistency assertions to test for fact existence to the abstract as suggested by CompSci Resources. |
19 March 2009 | Geoff Shuetrim |
Changed the term "target XBRL instance" to "input XBRL instance". Ensured that all usages of the terms input XBRL instance and output XBRL instance reference the term definition. |
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 22 June 2009. 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.