Common Warehouse Metamodel Avatar
  1. OMG Specification

Common Warehouse Metamodel — Open Issues

  • Acronym: CWM
  • Issues Count: 27
  • Description: Issues not resolved
Open Closed All
Issues not resolved

Issues Summary

Key Issue Reported Fixed Disposition Status
CWM12-71 Review the semantics of existing attribute types that are also CWM classes CWM 1.0 open
CWM12-57 CWM should consider generating XML Schemas, in both XMI 1.x and XMI 2.0 CWM 1.0 open
CWM12-70 Add a representation for sequence to CWM relational package CWM 1.0 open
CWM12-56 Make ChangeRequest useful CWM 1.0 open
CWM12-76 CWM Object resource package does not provide support for exceptions CWM 1.0 open
CWM12-64 The XML package should be revised/extended to represent XML schema metadata CWM 1.0 open
CWM12-53 Modeling and packaging guidelines CWM 1.0 open
CWM12-54 Rationalize 'Measurement' CWM 1.0 open
CWM12-69 Inconsistencies caused by changing Expression etc from Data Types to Classe CWM 1.0 open
CWM12-52 Warehouse processes missing physical information CWM 1.0 open
CWM12-61 Inadequate support for Organizational Structures CWM 1.0 open
CWM12-58 CWM should consider generating XMI 1.2 DTDs CWM 1.0 open
CWM12-73 consider changing DeployedComponent from being subclass of Core::Package CWM 1.0 open
CWM12-65 Generic Data Mining metamodel issue CWM 1.0 open
CWM12-60 CWM should consider using MOF 1.4 for it's metamodel CWM 1.0 open
CWM12-66 The metamodel for DTD should be reviewed CWM 1.0 open
CWM12-55 Predefined' values not defined in metamodel CWM 1.0 open
CWM12-59 Component Re-use unclear CWM 1.0 open
CWM12-62 Make it easier to interchange UML Models CWM 1.0 open
CWM12-77 supplierDependency reference is missing from ModelElement CWM 1.0 open
CWM12-68 Description, Document, ResponsibleParty should be made subtypes of Comment CWM 1.0 open
CWM12-74 package may fail to permit definition of transformations CWM 1.0 open
CWM12-75 XML Schema package issue CWM 1.0 open
CWM12-78 XML metamodel should be based on W3C XML Information Set CWM 1.0 open
CWM12-63 Practical changes to Contact metamodel CWM 1.0 open
CWM12-67 All OCL sections should be reviewed to ensure that they are complete CWM 1.0 open
CWM12-72 Identify precise CWM definition to which interchange doc. conforms CWM 1.0 open

Issues Descriptions

Review the semantics of existing attribute types that are also CWM classes

  • Key: CWM12-71
  • Legacy Issue Number: 4404
  • Status: open  
  • Source: Thematix Partners LLC ( Doug Tolbert)
  • Summary:

    The precise semantics of the use of the CWM Expression class (and
    its subclasses) as the type of attributes of CWM classes is not clearly
    delineated (as discussed at the 7/12/01 CWM RTF meeting in Danvers, MA).
    Review the semantics of existing attribute types that are also CWM classes
    and correct them as needed.

  • Reported: CWM 1.0 — Wed, 18 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

CWM should consider generating XML Schemas, in both XMI 1.x and XMI 2.0

  • Key: CWM12-57
  • Legacy Issue Number: 4511
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    Support for XMI for XML Schemas The above will probably be adopted at the September 2001 meeting. CWM should consider generating XML Schemas, in both XMI 1.x and XMI 2.0 flavors. Note that there is a new directory and naming structure that allows a single metamodel to have many physical artifacts at different versions with clarity of access.

  • Reported: CWM 1.0 — Sun, 19 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Add a representation for sequence to CWM relational package

  • Key: CWM12-70
  • Legacy Issue Number: 4430
  • Status: open  
  • Source: International Business Machines ( Dan Chang)
  • Summary:

    A sequence is a relational database object that allows the automatic generation of values. Sequences are ideally suited to the task of generating unique key values. Applications can use sequences to avoid possible concurrency and performance problems resulting from the generation of a unique counter outside the database. Currently, the CWM Relational package does not provide a representation for sequence. It should be added.

  • Reported: CWM 1.0 — Thu, 26 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Make ChangeRequest useful

  • Key: CWM12-56
  • Legacy Issue Number: 4515
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    This should be part of BusinessInformation: it is not at all specific to WarehouseOperations since one could request changes to database schemas, transformations or pretty much anything.

    'isActive' would be better than 'completed' for ChangeRequest, and would observe the convention of using 'is' for booleans. Moreover it should be a derived nonchangeable attribute to avoid inconsistency with 'status'.

    The reference from ChangeRequest to ModelElement should be 0..* since the request might be to create something new that cannot yet be referred to!

    The following are considered essential for most ChangeRequests: 1) two multivalued optional references to ResponsibleParty to indicate: a) raiser b) actionee 2) optional single-valued integer attribute 'priority' (larger value = more important), constrained to be non-negative. 3) optional single-valued string attributes 'raisersIdentifier' and 'identifier' (representing an id allocated by the raiser and that used internally by the warehouse management system). 4) optional multivalued string attribute 'history' to describe events in managing the request. 5) optional string attribute 'resolution' to decribe what actually happened (e.g. how the modelElements were changed, why the request was rejected etc).

  • Reported: CWM 1.0 — Sun, 19 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

CWM Object resource package does not provide support for exceptions

  • Key: CWM12-76
  • Legacy Issue Number: 4399
  • Status: open  
  • Source: Thematix Partners LLC ( Doug Tolbert)
  • Summary:

    Modern object-oriented programming languages such as Java and C#
    support the notion of exceptions as first class objects. However, the CWM
    Object resource package does not provide support for exceptions. Although
    exceptions might be added to extension packages specifically designed for
    each language that needs them, such an approach would not promote
    interchange of exceptions between data warehouse components written in
    different languages. This problem will become particularly accute for .NET
    languages in which particular exceptions are defined by language independent
    components (such as the .NET CLR libraries) and can be returned to
    application components written in any of a group of languages. Suggested
    approaches to resolving this difficulty might include (1) adding exceptions
    to the CWM Behavioral package or (2) creating an Object package and placing
    the new exception classes in it.

  • Reported: CWM 1.0 — Wed, 18 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

The XML package should be revised/extended to represent XML schema metadata

  • Key: CWM12-64
  • Legacy Issue Number: 4467
  • Status: open  
  • Source: International Business Machines ( Dan Chang)
  • Summary:

    This issue is to capture what has been stated in Chapter 12 of the CWM specification. The XML package should be revised and extended to represent XML Schema metadata as soon as XML Schema is adopted by W3Cas a recommendation (which happened in 5/01).

  • Reported: CWM 1.0 — Fri, 3 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Modeling and packaging guidelines

  • Key: CWM12-53
  • Legacy Issue Number: 4583
  • Status: open  
  • Source: Thematix Partners LLC ( Doug Tolbert)
  • Summary:

    Metamodels described in the CWM specification employ certain
    modeling techniques and packaging styles in preference to others. However,
    the current text of the specification does not clearly delineate, or provide
    a rationale for, which modeling techniques and packaging styles are
    preferred and which are not. Because stylistic consistency is an important
    part of promoting both understandability and implementability, text should
    be added to the specification (possibly in Chapter 6) delineating preferred
    modeling techniques and packaging. Such documentation will provide guidance
    to submitters of enhancements to existing CWM metamodels and of new or
    replacement metamodel packges.

  • Reported: CWM 1.0 — Wed, 26 Sep 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Rationalize 'Measurement'

  • Key: CWM12-54
  • Legacy Issue Number: 4516
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    This should be part of Foundation (probably Expressions or BusinessInformation): it is not at all specific to WarehouseOperations since one could apply measures to tables (for expected volumes), transformations etc.

    Measurement should have an optional reference to an Expression to define how the value has/should be calculated.

  • Reported: CWM 1.0 — Sun, 19 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Inconsistencies caused by changing Expression etc from Data Types to Classe

  • Key: CWM12-69
  • Legacy Issue Number: 4407
  • Status: open  
  • Source: International Business Machines ( Dan Chang)
  • Summary:

    Expression and their subtypes (BooleanExpression, etc.) were changed from Data Types (in the CWM Adapted Specification) to Classes in CWM 1.0. As a result, it caused design inconsistency in CWM. For example, ExpressionNode inherits from Element. This was designed originally based on the fact that Expression was a Data Type and could not be subclassed. It should now inherit from Expression, which can be subclassed. The CWM RTF should review and revise all such inconsistencies caused by changing Expression, Multiplicity, etc. from Data Types to Classes.

  • Reported: CWM 1.0 — Tue, 24 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Warehouse processes missing physical information

  • Key: CWM12-52
  • Legacy Issue Number: 4519
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    It's not at all clear how one links from a WarehouseProcess or TransformationExecution to the physical information that it is applied to (e.g. if the same information is replicated across a number of physical locations which is actually used as the source of a datawarehouse load?).

    At the Process level there is the opportunity for some sophistication (e.g. to list a number of physical sources/destinations in priority order); at the execution level one should record the actual instance used.

    Similarly one may want to specify and record which DeployedComponent(s) should be used to carry out the transformation.

  • Reported: CWM 1.0 — Sun, 19 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Inadequate support for Organizational Structures

  • Key: CWM12-61
  • Legacy Issue Number: 4473
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    Sections 8.3 and 8.3.1.7 justify ResponsibleParty inheriting from Namespace in that it can be used for "capturing organizational structures or similar relationships". This is not only quite obscure but is inadequate for even very simple and common Warehouse-oriented situations - due to the strict composition semantics of Namespace. In particular it does not allow a single person to belong to more than one Position/Team, nor does it allow the representation of matrix/management relationships which are very common. Moreover it does not allow the separation of two very different concepts: packaging of models and organizational relationships.

    An example 'test' scenario is of 2 support teams: one for Corp Database A, another for Corp Database B. Both will always have the same Manager (regardless of who is currently filling that position) and make use the same Performance Specialist, John Wicks.

    It is proposed that CWM adopt a simple but specific Organization Structure metamodel (no more than 5 classes such as Unit, Position, Person) that also aims for consistency with OMG's recently adopted Organizational Structure Facility.

  • Reported: CWM 1.0 — Mon, 6 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

CWM should consider generating XMI 1.2 DTDs

  • Key: CWM12-58
  • Legacy Issue Number: 4510
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    Support for XMI 1.2 XMI 1.2 will probably be adopted at the September 2001 meeting. CWM should consider generating XMI 1.2 DTDs. Note that there is a new directory and naming structure that allows a single metamodel to have many physical artifacts at different versions with clarity of access.

  • Reported: CWM 1.0 — Sun, 19 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

consider changing DeployedComponent from being subclass of Core::Package

  • Key: CWM12-73
  • Legacy Issue Number: 4402
  • Status: open  
  • Source: Thematix Partners LLC ( Doug Tolbert)
  • Summary:

    In the SoftwareDeployment package, consider changing
    DeployedComponent from being a subclass of Core::Package to being as
    subclasss of Core::Subsystem. This change preserves the package nature of
    DeployedComponents and, at the same time, adds the ability of
    DeployedComponents to have features (because Core::Subsystem is a subclass
    of Core::Classifier, as well as Core::Package).

  • Reported: CWM 1.0 — Wed, 18 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Generic Data Mining metamodel issue

  • Key: CWM12-65
  • Legacy Issue Number: 4462
  • Status: open  
  • Source: International Business Machines ( Dan Chang)
  • Summary:

    The Data Mining metamodel contains a sub-metamodel on classification/categorization, which is generic and which can be useful outside of data mining but in a data warehousing/business intelligence context. Following the tradition of CWM's design emphasis on modularity and reuse, this sub-metamodel should be made a separate package from the Data Mining package.

  • Reported: CWM 1.0 — Fri, 3 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

CWM should consider using MOF 1.4 for it's metamodel

  • Key: CWM12-60
  • Legacy Issue Number: 4509
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    Support for MOF 1.4 MOF 1.4 will probably be adopted at the September 2001 meeting. CWM should consider using MOF 1.4 for its metamodel, which will bring particular benefits in the area of DataTypes. Note that there is a new OMG directory and naming structure that allows a single metamodel to have many physical artifacts at different versions with clarity of access.

  • Reported: CWM 1.0 — Sun, 19 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

The metamodel for DTD should be reviewed

  • Key: CWM12-66
  • Legacy Issue Number: 4461
  • Status: open  
  • Source: International Business Machines ( Dan Chang)
  • Summary:

    This is an issue deferred from the CWM FTF. The metamodel for DTD should be reviewed, and revised if necessary, to make sure that it fully represents DTD information and that it is consistent with the new metamodel for XML Schema.

  • Reported: CWM 1.0 — Fri, 3 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Predefined' values not defined in metamodel

  • Key: CWM12-55
  • Legacy Issue Number: 4513
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    The 'predefined' values for SoftwareDeployment::SoftwareSystem.type (and subtype) should be formally defined as Constants in the metamodel. Similarly for WarehouseOperation::ChangeRequest.status and WarehouseOperation::Measure.type (there are probably others).

  • Reported: CWM 1.0 — Sun, 19 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Component Re-use unclear

  • Key: CWM12-59
  • Legacy Issue Number: 4512
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    By using the inherited ElementOwnership association to link SOftwareSystem and Component, this would seem to prevent the same component being reused in many systems. Though an Import association is depicted in Figure 8-7-1, nothing is said in the text about its semantics in this context: typically this would be used just for definitions/types ("extending the namespace" according to the description in the Core model) and not something that would need to be physically deployed as part of the SoftwareSystem.

    Proposed resolution: Introduce a new many-to-many shared aggregation to link SoftwareSystem and Component.

  • Reported: CWM 1.0 — Sun, 19 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Make it easier to interchange UML Models

  • Key: CWM12-62
  • Legacy Issue Number: 4470
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    CWM uses a subset of UML for practical reasons. It also delegates the modeling of Object Oriented resources to that subset. However the way this is currently done makes it unnecessarily hard to take a model exported from a UML tool and import it as the model of an OO resource in CWM.

    CWM should provide support e.g. via metamodel and/or documented best practice (e.g. use of XMI namespaces) for this.

  • Reported: CWM 1.0 — Mon, 6 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

supplierDependency reference is missing from ModelElement

  • Key: CWM12-77
  • Legacy Issue Number: 4398
  • Status: open  
  • Source: International Business Machines ( Dan Chang)
  • Summary:

    The supplierDependency reference is missing from ModelElement, which existed in the CWM Adapted Specification.This change makes the model illogical and unbalanced. Dependency is always defined between two ModelElements (a client and a supplier). Its definition involves two associations and four association ends. Either the supplierDependency reference should be put back (which makes a more flexible model) or the client reference on Dependency should also be removed (which makes a more restrictive model, but at least it is logical and balanced). (This is a revised write-up for issue #3398.)

  • Reported: CWM 1.0 — Fri, 20 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Description, Document, ResponsibleParty should be made subtypes of Comment

  • Key: CWM12-68
  • Legacy Issue Number: 4460
  • Status: open  
  • Source: International Business Machines ( Dan Chang)
  • Summary:

    This is an issue deferred from the CWM FTF. Description, Document and ResponsibleParty should be made subtypes of Comment, allowing use of the corresponding reference on ModelElement.

  • Reported: CWM 1.0 — Fri, 3 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

package may fail to permit definition of transformations

  • Key: CWM12-74
  • Legacy Issue Number: 4401
  • Status: open  
  • Source: Thematix Partners LLC ( Doug Tolbert)
  • Summary:

    Usage experience with the CWM 1.0 Transformation package has
    uncovered several situations in which the package may fail to permit
    definition of transformations that fully capture the intent of implementors.
    Such problems have appeared in several unrelated modeling venues and have
    led some implementors to seek alternative means for describing
    transformations. The existing transformation package should be reviewed by
    the RTF and changed as needed to improve its ability to represent the
    breadth of transformation semantics found in practical usage scenarios. As
    part of this effort, the RTF should consider incorporating the existing
    TypeMapping package into an evolved Transformation package – TypeMappings
    are, after all, really just lightweight transformations.

  • Reported: CWM 1.0 — Wed, 18 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

XML Schema package issue

  • Key: CWM12-75
  • Legacy Issue Number: 4400
  • Status: open  
  • Source: Thematix Partners LLC ( Doug Tolbert)
  • Summary:

    The planned XML Schema package proposed for inclusion in CWM 1.1
    should be cognizant of and wherever possible, equivalent to, the XML Schema
    model planned for the inclusion in the XMI specification. Within reason,
    corresponding XML Schema-specific class in the two specifications show share
    the same names, attributes, and relationships to other classes.

  • Reported: CWM 1.0 — Wed, 18 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

XML metamodel should be based on W3C XML Information Set

  • Key: CWM12-78
  • Legacy Issue Number: 4247
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    XML metamodel should be based on W3C XML Information Set. W3C has a standard called XML Information Set http://www.w3.org/TR/xml-infoset/ (at Candidate Recommendation status) "This specification defines an abstract data set called the XML Information Set (Infoset). Its purpose is to provide a consistent set of definitions for use in other specifications that need to refer to the information in a well-formed XML document"

    In effect it defines an information model for XML with the following Information Items (the equivalent of classes in CWM): Document, Element, Attribute, Processing Instruction, Unexpanded Entity Reference, Character, Comment, Document Type Declaration, Unparsed Entity,Notation, Namespace. It would seem that since this is what W3C says should be modeled for XML documents then this should be the basis of the CWM XML model (the content part as opposed to the Schema part), or at least CWM should specify how it maps to this Information Set.

  • Reported: CWM 1.0 — Tue, 3 Apr 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Practical changes to Contact metamodel

  • Key: CWM12-63
  • Legacy Issue Number: 4472
  • Status: open  
  • Source: agnos.ai UK Ltd ( Pete Rivett)
  • Summary:

    These are gained from having tried to use the model in real situations.

    a) Add new attribute Contact.applicability: String (0..1), to allow a fuller description of when that

    contact should be used (e.g. "After hours or weekend emergencies only: when completion of a

    time-critical run is threatened").

    b) the associations between COntact and its constituent parts (Telephhone etc) should be shown as aggregations (not compositions) for clarity. This will have no effect on generated code/DTDs.

    c) split the phoneNumber attribute into its constituent parts. This is because the actual number to ring is dependent on context), and there may be uses where automatic dialing is required (e.g. for fax/pager access to contacts). [It is assumed that the calling progam knows what country/area it is dialing from). The proposed replacement attributes (all optional and of type String) are: countryCode inCountryAreaPrefix (e.g. for UK it would be "0" - one dials +44 1202 449419 outside UK but 01202 449419 inside UK) areaCode corePhoneNumber.

  • Reported: CWM 1.0 — Mon, 6 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

All OCL sections should be reviewed to ensure that they are complete

  • Key: CWM12-67
  • Legacy Issue Number: 4459
  • Status: open  
  • Source: International Business Machines ( Dan Chang)
  • Summary:

    This is an issue deferred from the CWM FTF. Per recommendation from the Architecture Board, all OCL sections should be reviewed to ensure that they are complete

  • Reported: CWM 1.0 — Fri, 3 Aug 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT

Identify precise CWM definition to which interchange doc. conforms

  • Key: CWM12-72
  • Legacy Issue Number: 4403
  • Status: open  
  • Source: Thematix Partners LLC ( Doug Tolbert)
  • Summary:

    Provide in the body of a CWM interchange document, a means for
    identifying the precise CWM definition to which the interchange document
    conforms. Something similar to the way the XML documents identify the URI
    of the XML definition they conform to would do nicely. Such a mechanism in
    effect creates a name space within which the contents of the CWM interchange
    document can be evaluated. Useful side effects of having such a namespace
    include: (1) the definition of CWM extension packages without the present
    need that they be accompanied by the CWM definition itself, (2) a framework
    in which Universally Unique Identifiers (UUIDs) can be defined for each CWM
    object. Several requests for CWM UUIDs have already been received
    informally.

  • Reported: CWM 1.0 — Wed, 18 Jul 2001 04:00 GMT
  • Updated: Wed, 11 Mar 2015 11:15 GMT