View source for Context Data Model 1.1 Open Issues

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== Open Issues ==
# Can we represent closed (non-mixed) types in OWL so that the LDAP CP can represent its schema?
# 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?)
# 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.) 
# 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: [http://dev.eclipse.org/viewsvn/index.cgi/org.eclipse.higgins/trunk/doc/org.eclipse.higgins.doc/Higgins-Data-Model-Intro.ppt?root=Technology_SVN&view=co Higgins Data Model Intro.PPT]
# 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]
# 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?
# 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]
# Need to close on [[EntityId]] requirements and design decisions as documented on [[EntityId Requirements]].

==Additions Needed==
# 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)
# 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 ==
# 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)
# Mixed attribute value data types
## Daniel points out that it would still be good to pass type on each value add:
### http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03816.html
### http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03818.html (and follow-ups)
## Resolution: we can mix types.
# Can an attribute have mixed values consisting of both simple and complex? 
## Resolution: Yes.
# Many same-types attributes
## http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03806.html
## Resolution: No. (We should document that this isn't allowed/possible)
# Allow zero-valued attributes
## http://dev.eclipse.org/mhonarc/lists/higgins-dev/msg03810.html
## 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.
# Replacement for Node (by vote, winner was Entity)

== LDAP-specific Issues ==
* [[LDAP Issues and To-Dos]] --open issues specifically related to LDAP schema