Context Data Model 1.1 Open Issues

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Open Issues

1. Can we represent closed (non-mixed) types in OWL so that the LDAP CP can represent its schema?
2. Ability to declare user-defined Classes to be 'closed', that is instances of them should follow the class definition, but not include any other "extra" properties. (same as previous?)
3. Closed or open simple data types
   • http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03821.html
   • Paul asserts that we have the ability already to specify a format constraint along with a data type. For example, one could say the data type of an attribute is normalizedString, but constrained to a pattern that looks like a telephone number
   • We can do this by creating a Data Range. A Data Range has a base XML Schema type (e.g. string) as well as all of the XML Schema facets (e.g. pattern, etc.)
4. Tony: We don't have a simplified description of the data model
   • Need a simple-to-follow set of pictures that explain the data model
   • This PPT was updated to the latest concepts terms and improved a bit based on feedback from the Jan/Provo F2F: Higgins Data Model Intro.PPT
5. This is a runtime data model, there are not yet any tools that can create the graphs that I think folks might need. Restating: The data mode is an un-typed mode, (no sub-classes) makes you look at each instance to determine its type, this is not suitable for data mining and creating graphs of the data characteristic. [from Tony 2/21 higgins-dev email]
6. When using relations there is now way to tell what relation we are really talking about. [from Tony 2/21/08 higgins-dev email]. Restated by Paul in 2/21/08 email: Given Entity (E1) that has two Entity Relations emanating from it, e.g one pointing to E2 and another pointing to E3, then are you saying that we’re lacking a way to “tag” or otherwise distinguish between these two Entity Relations?
7. Another "core" subclass to consider is Account (or something that represents the attributes needed to authenticate to a system). It is important to figure this out early in the subclassing, because many repositories represent accounts as additional attributes of a Person and other repositories represent the account as separate from the Person. In addition not all accounts are Persons, the account could represent a device, application, or a group. [David K-M email of 2/22/08 on higgins-dev]
8. Need to close on EntityId requirements and design decisions as documented on EntityId Requirements.

Additions Needed

1. New Classes and Attributes to support Access Control (e.g. PolicySet, Policy, higgins:audience (permission to whom), higgins:operation (what operation is permitted) higgins:resource (thing being protected)
2. I-Card Class and associated Attributes: standard way to represent ISIP M- and P-Cards. Also an R-Card Class (subclass of I-Card)

Resolved Issues

1. BlankEntities
   • The current HOWL and the current IdAS don't make a distinction between an Entity and a BlankEntity. In the proposed HOWL update the BlankEntity term is introduced. Currently both it and Entity inherit separately from OWL:Thing.
   • Alternatives:
     • (a) Define Entity to be a subclass of BlankEntity: i.e. an Entity is a BlankEntity with a single literal EntityId attribute
     • (b) Don't introduce this distinction and call them both Entities
   • See HOWL Update 1.1.103 for proposed resolution to this issue (based on (b) above)
2. Mixed attribute value data types
   1. Daniel points out that it would still be good to pass type on each value add:
      1. http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03816.html
      2. http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03818.html (and follow-ups)
   2. Resolution: we can mix types.
3. Can an attribute have mixed values consisting of both simple and complex?
   1. Resolution: Yes.
4. Many same-types attributes
   1. http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03806.html
   2. Resolution: No. (We should document that this isn't allowed/possible)
5. Allow zero-valued attributes
   1. http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03810.html
   2. Resolution: we should not allow zero-valued attributes in the model per se. It is true that for access control reasons, no value will be returned in some cases.
6. Replacement for Node (by vote, winner was Entity)

LDAP-specific Issues

• LDAP Issues and To-Dos --open issues specifically related to LDAP schema