Decision Model and Notation Avatar
  1. OMG Specification

Decision Model and Notation — Open Issues

  • Acronym: DMN
  • Issues Count: 12
  • Description: Issues not resolved
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Issues not resolved

Issues Descriptions

Support for function types in metamodel and XSD

  • Key: DMN14-61
  • Status: open  
  • Source: Goldman Sachs ( Octavian Patrascoiu)
  • Summary:

    The DMN metamodel & the XSD schema do not support definition of function type. For example, a construction as the one below is not supported:

    <functionDefinition name='add_type' returnType='number'>
                    <param name='a' typeRef='number'>
                    <param name='b' typeRef='number'>
  • Reported: DMN 1.2b1 — Fri, 22 Feb 2019 11:57 GMT
  • Updated: Wed, 21 Apr 2021 00:53 GMT

Spec does not clarify meaning of hex value

  • Key: DMN14-56
  • Status: open  
  • Source: fujitsu america ( keith swenson)
  • Summary:

    Rule #66 on page 111 says that a character in a string can be expressed as:

    "\u", hex digit, hex digit, hex digit, hex digit

    For example "\uD83D"

    That is, exactly four hex digits. I believe the intent is that FEEL only allows exactly four digits, and does not allow the kinds of expressions that we see in the EBNF.

    What is never specified is the exact meaning of that hex value. There are two possibilities:

    (a) Is that value a Unicode code point? In this case it is easy, the hex value is the code point value, however because you are limited to 64K characters, and not the 1.1M character range normally considered, and not even the values that are mentioned in the spec as having significance.

    (b) Or is it a UTF-16 code value? UTF-16 has encoding rules about values in the surrogate character range. In UTF-16 a high-surrogate-code value must be followed by a low-surrogate-code value or else the sequence of values is invalid and undefined. Using surrogate characters you can address the entire 1.1million characters but the user is required to understand about surrogate pairs.

    The spec never mentions that UTF-16 encoding is required! It always uses "Unicode" and talks about "characters" and "code points". It does not mention anything about surrogate pairs. It never says that these values a "just like Java" or any other UTF-16 implementation.

    Page 124 says that the FEEL string value is the same as java.lang.String. Should we infer from that that internal representations must be in UTF-16? however it also says that it is equivalent to an XML string (which is NOT constrained to UTF-16) and PMML string which I looked up and seems to be based on XML. XML allows characters to be expressed as &#nnnn ; That is an ampersand, a hash, a decimal number, terminated by a semicolon. In this case, the decimal value is the actual code point, and not the UTF-16 value. So page 124 does not say unambiguously that Java defines the string values that can be used.

    Unicode is mentioned only in three places: on page 108 (about EBNF character ranges), page 111 that tokens are a sequence of unicode characters, page 114 in an example.

    While it might be nice to be a "code point", the syntax clearly limits you to four digits leaving you no way to express larger code point values. If it was a code point you would be limited to only specifying 64,000 character (minus several thousand code points that not allowed for various reasons).

    The easiest repair is to state clearly that the \u notation assumes that UTF-16 is being used to encode the strings, and that UTF-16 rules must be used when specifying hex values for characters.

    I believe most implementations to date have assumed that these are UTF-16 code unit values. That is what Java does. That is what JavaScript does. I don't know of any environments that do anything different for this kind of expression.

  • Reported: DMN 1.2b1 — Fri, 8 Feb 2019 18:33 GMT
  • Updated: Wed, 21 Apr 2021 00:53 GMT

Convenience documents

DMN 1.3 Metamodel

Knowledge Package Model and Notation (KPMN)

  • Key: DMN14-50
  • Status: open  
  • Source: BPM Advantage Consulting ( Stephen White)
  • Summary:

    A Knowledge Package is mechanism for packaging and distributing a set of BPM+ models (the knowledge)
    A Knowledge Package references separate, but connected BPM+ models (BPMN Processes, CMMN Cases, and DMN Decision Services)
    KPMN is focused solely on the BMI behavioral standards
    A Knowledge Package also contains a Data Item library for the data that will be used by the BPM+ models
    A Situational Data Model and Notation (SDMN) is also being proposed as a potential BMI standard to be added to the BPM+ stack (see separate presentation on this topic)
    A Knowledge Package also contains metadata about the topic of the package to aid in understanding the content and to find appropriate Knowledge Packages
    We are still exploring the relationships between KPMN and Provenance and Pedigree
    KPMN includes a diagram to illustrate the scope of the Knowledge Package’s content (a Knowledge Model Diagram)

  • Reported: DMN 1.2b1 — Tue, 10 Sep 2019 17:59 GMT
  • Updated: Mon, 6 Jan 2020 12:59 GMT
  • Attachments:

Situational Data Model and Notation (SDMN)

  • Key: DMN14-49
  • Status: open  
  • Source: BPM Advantage Consulting ( Stephen White)
  • Summary:

    Situational Data is the set of Data Items and their structures that are needed for the performance and understanding of a Knowledge Package Model.
    The details of the Data Items will usually be a subset of the “official” complexity of those items in the environment of the Knowledge Package Model.
    For example, the official definition of the Data Item for Blood Pressure (in healthcare) includes more than 50 properties. A Data Item in a Situational Data Model may need only 2 of those properties for execution of the Processes, Cases, and or Decision Services.
    Semantic References can be added to link the Data Item to the “official” details.
    Uses of the Data Items in BPM+ models that determine the scope of Situational Data include:
    Data required for DMN Decisions
    Data required for BPMN Gateways transitions
    Data required to be passed to/from services invoked by BPMN and CMMN
    Data required to trigger Sentries in CMMN

  • Reported: DMN 1.2b1 — Tue, 10 Sep 2019 18:04 GMT
  • Updated: Mon, 6 Jan 2020 12:58 GMT
  • Attachments:

"instance of" not possible with some built-in functions

  • Key: DMN14-66
  • Status: open  
  • Source: Montera Pty Ltd ( Greg McCreath)
  • Summary:

    some built in functions are overloaded in that they can have multiple signatures. So, say, performing an "instance of" to compare against the function "min" is meaningless as the signature is not known unless it is invoked.

    Unless the type system is to take into account overloaded functions?

  • Reported: DMN 1.2b1 — Thu, 15 Nov 2018 08:15 GMT
  • Updated: Fri, 3 Jan 2020 20:51 GMT

Inconsistency DMNv1.2 dropping [a]=a and get entries example

  • Key: DMN14-65
  • Status: open  
  • Source: Red Hat ( Matteo Mortari)
  • Summary:

    Since DMNv1.2 the spec dropped the equivalence of:

    [a] = a

    because it does not apply to the statement that

    a singleton list L, when used in an expression where a list is not expected, behaves as if L[1] is written.

    So the expression

    [a] = a

    on DMNv1.2 is expected to return false.

    However, in section Context of the spec, it provides the following statement for the get entries function:

    To retrieve a list of key,value pairs from a context m, the following built-in function may be used: get entries(m).
    For example, the following is true:

    get entries({key 1 : "value 1 "})[key="key 1 "].value = "value 1 "


    get entries({key1 : "value1"})[key="key1"].value = "value1"
      by substitution:
    [ { key : "key1", value : "value1" } ][key="key1"].value = "value1"
    [ { key : "key1", value : "value1" } ].value = "value1"
    [ "value1" ] = "value1"

    according to DMNv1.2 should be false

    By the same principle that the DMNv1.2 for the following literal expression:

    [123] = 123

    on DMNv1.2 is expected to be false

  • Reported: DMN 1.2b1 — Wed, 30 Jan 2019 14:43 GMT
  • Updated: Fri, 3 Jan 2020 20:51 GMT

Clean up example xml files

  • Key: DMN14-57
  • Status: open  
  • Source: Oracle ( Gary Hallmark)
  • Summary:

    Sample xml files have Trisotech extension elements. These should be removed prior to publication.

  • Reported: DMN 1.2b1 — Tue, 28 May 2019 16:52 GMT
  • Updated: Fri, 3 Jan 2020 20:51 GMT

Provide better spec and examples for Equality, Identity, and Equivalence

  • Key: DMN14-58
  • Status: open  
  • Source: Oracle ( Gary Hallmark)
  • Summary:

    the builtin function is() refers to this section. It should cover some pos/neg examples of equality vs. identity, and explain aggregate elements in D, e.g. list of structures.

  • Reported: DMN 1.2b1 — Tue, 28 May 2019 16:40 GMT
  • Updated: Fri, 3 Jan 2020 20:51 GMT

Friendlier handling of null values

  • Key: DMN14-59
  • Status: open  
  • Source: Oracle ( Gary Hallmark)
  • Summary:

    E.g. in aggregation, default for item definition, see examples in DMN-2, where filters like [item!=null] are used repeatedly

  • Reported: DMN 1.2b1 — Tue, 21 May 2019 16:53 GMT
  • Updated: Fri, 3 Jan 2020 20:51 GMT

Temporal precision inconsistencies

  • Key: DMN14-53
  • Status: open  
  • Source: Trisotech ( Denis Gagne)
  • Summary:

    The spec sometimes refers to the temporal precision as milliseconds and sometimes to seconds. Sections, and refer to Seconds whereas table 48 offers a semantic of Milliseconds

  • Reported: DMN 1.2b1 — Tue, 16 Jul 2019 14:02 GMT
  • Updated: Fri, 3 Jan 2020 20:51 GMT