Information Description

This page is intended to give a brief overview of the classes identified in the information model. The current model was produced by ChrisGreenhalgh following a brainstorm at IF-3, on 2003-02-11. For a diagram, and comments on issues to be clarified, see MyGridInformationRepository.

This page is experimental. The advantage of using TWiki is that we can incorporate links to examples on other TWiki pages. A list of the classes in the information model and the relationships between them is intended to be browsed in multiple ways, rather than form a linear document.

This page is not yet complete (2003-02-20)

We are currently working on a revised design and implementation after the experience gained in IF4. Design notes can be found in

• information-model-design-notes-post-if4.doc:

ChrisWroe - 30 Jun 2003

UserDescription has more information on how to describe a user.

-- ChrisWroe - 08 Sep 2003

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See also InformationModel for further work in this area.

NickSharman - 18 July 2003

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Index

Name		Superclass
ActionDefinition	Entity	DataThing
ActionPerformed	Entity	ProxyThing
Annotation	Entity	DataThing
createdBy	Relationship
createdIn	Relationship
DataThing	Entity	Thing
describedByIn	Relationship
Experiment	Entity	WorkContext
GridResource	Entity	ProxyThing
Input	Entity?	(models input relationship)
involvedIn	Relationship
LabBookReport	Entity	Report
Notification	Entity	DataThing
Organisation	Entity	WorkContext
originAction	Relationship	models output
partOf	Relationship
performedBy	Relationship
Project	Entity	WorkContext
ProvenanceLog	Entity	Report
ProxyThing	Entity	Thing
Report	Entity	DataThing
Service	Entity	GridResource
ServiceDescription	Entity	DataThing
SingingAnnotation	Entity	Annotation
subject	Relationship
subscription	Relationship
Subscription	Entity	WorkContext
Thing	Entity	None (Top)
User	Entity	ProxyThing
WFDefinition	Entity	ActionDefinition
WFInstance	Entity	ActionPerformed
WorkContext	Entity	ProxyThing

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Entities

Thing

A Thing is the base entity in the information model. Things are divided into two broad categories: DataThing which are those things that we can store in a database, and ProxyThing which are those, such as users, where we can only store a proxy. These are exclusive subsets. A Thing can never be both a DataThing and a ProxyThing. The properties of Thing are:

• uri : java.net.URI
  • all Things have a unique identifier (e.g. LSID)
• title : String
• description :String
• createdTime : String
• createdBy : User
  • all Things are created by some User
• conceptType : java.net.URI
• comment : String
  • The property comment is additional clarification information provided by the Thing's creator. There is a separate entity Annotation that is used to record third party information about any Thing.
• additionalMetaData : NameValuePair^?[]

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DataThing

DataThing represents all the entities that can be stored in a database. This includes domain entities, such as a protein sequence in the bioinformatics domain, and myGrid entities, reports, annotations, action definitions and notifications. The properties of DataThing in addition to those inherited from Thing are:

• value : byte [] - the actual report, annotation, protein sequence etc.
• concreteType : String
• format : String
• language : String
• versioned : Boolean
• baseURI : java.net.URI
  • this was intended to be the version-independent part of e.g. an LSID URI, whereas uri in Thing is the full URI including any version suffix - cmg.
• version : Int
• replaced : boolean
• delible : boolean - able to be deleted
• deleted : boolean
  • Place-holder - does it ever make sense to delete (or garbage collect) a (presumably large) value, but leave all the metadata in place for provenance purposes? If so, use this.
• origin : enum
  • all DataThings come from somewhere. User might use a client to type in the value directly, or upload it. An action performed might create the DataThing as an interim or final output.
• originExternalUri : java.net.URI
  • used for DataThings that come from outside myGrid
• originAction : ActionPerformed
  • used for DataThings that come from actions recorded in myGrid
• originActionOutputName : String
  • actions may produce multiple outputs, which can be distinguised by name

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ProxyThing

ProxyThing represents all the entities where only a proxy of the actual thing can be included in a database. This includes: users, service/workflow invocations, experiments, organisations, grid resources.

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Annotation

An Annotation can be attached to an Thing. The Annotation itself is a DataThing. In addition to the properties it inherits from DataThing, the Annotation has a subject property whose value is the Thing to which the Annotation refers.

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SingingAnnotation

A SigningAnnotation is an Annotation with the additional properties: subjectHash and digitalSignature. This supports a degree of cryptographic authentication of the annotation and the state of the thing when it was annotated.

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User

A User is a ProxyThing, that represents myGrid users. The properties of User in addition to those inherited from ProxyThing are:

• email : String
• userAgent : URL
• DN : String
• phone : String
• fax : String
• sms : String

As a User is a Thing, all Users have a createdBy relationship with another User. The bootstrap will have to create a initial root User

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WorkContext

A WorkContext is the general facility for structuring work within myGrid. The subclasses of WorkContext include: Experiment, Organisation, Project, and (provisionally) Subscription.

• A WorkContext is a ProxyThing and therefore is createdBy a User.
• A WorkContext can be partOf 0 or more WorkContexts, and conversely can have 0 or more WorkContexts that are partOf it.
• A Thing is createdIn a WorkContext
  • As a WorkContext is a ProxyThing the initial WorkContext like the initial User will require a special bootstrap.
• 0 or more Things can be involvedIn a WorkContext

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Experiment

An Experiment is a WorkContext.

• an Experiment is describedBy a LabBookReport

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Organisation

An Organisation is a WorkContext.

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Project

An Project is a WorkContext.

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Subscription

An Subscription is a WorkContext.

• TODO Is *Subscription a kind of WorkContext in which notifications are generated, or a new Thing? (see MyGridInformationRepository)

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Notification

An Notification is a DataThing. It has the additional property:

• subscription : Subscription

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Report

A Report is a DataThing. Unlike an Annotation a Report does not have a specific subject.

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LabBookReport

A LabBookReport is a Report.

• an Experiment is describedBy a LabBookReport

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ProvenanceLog

A ProvenanceLog is a Report.

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ActionProvenanceLog

An ActionProvenanceLog is a ProvenanceLog.

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ActionDefinition

A ActionDefinition is a DataThing. This could be the definition of how to invoke a web service, a web service with a specific interface style, such as soaplab, a grid service, or a workflow.

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WFDefinition

A WFDefinition is a ActionDefinition. It includes the workflow source in WSFL.

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ActionPerformed

An ActionPerformed is a ProxyThing. It is the proxy for some action that was (or is being?) performed. Note that there is a distinction between the ActionPerformed and the ActionProvenanceLog which is a Report of what happenend.

• an ActionPerformed may be the originAction of 0 or more DataThings
  • these are the outputs of the ActionPerformed
• an ActionPerformed may have 0 or more Inputs (property is _hasInput_)
  • these identify the inputs of the ActionPerformed
• an ActionPerformed is definedBy: an ActionDefinition
• an ActionPerformed is describedBy an ActionProvenanceLog
• an ActionPerformed is performedBy an Service

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WFInstance

A WFInstance is a ActionPerformed. It includes a nativeURI property, which is the unique identifier given to the workflow instance by the workflow enactment engine.

• an WFInstance is definedBy an WFDefinition

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Input

An Input is not a Thing. It is a description of the fact that a DataThing was an input to an ActionPerformed. A separate record is needed as the same DataThing may be input to several ActionPerformed, for example when running a new version of a WFDefinition with the same inputs. An Input has an inputName property that identifies the parameter name of the ActionPerformed.

(It is possible for the same DataThing to be passed to an ActionPerformed as the value of more than one distinct parameter.)

• an Input has dataThing a DataThing
• an ActionPerformed may have 0 or more Inputs

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GridResource

An GridResource is a ProxyThing.

• an GridResource has a property nativeURI : URI
  • This is the URI of the resource itself. The GridResource will also have a property uri from Thing, but this will be the uri of the proxy within myGrid rather than the GridResource itself.
  • There will also be a disctinction between the actual owner/creator of the external resource, and the myGrid user who created the proxy

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Service

An Service is a GridResource.

• a Service is describedBy a ServiceDescription
• an ActionPerformed is performedBy a Service

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ServiceDescription

A ServiceDescription is a DataThing.

• a Service is describedBy a ServiceDescription

Also see ServiceDescription. -- ChrisWroe - 21 Feb 2003

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Relationships

subject

A Thing is subject of an Annotation

createdBy

A Thing is createdBy a User

createdIn

0 or more Things are createdIn a WorkContext

involvedIn

0 or more Things are involvedIn a WorkContext

partOf

0 or more WorkContexts can be partOf of 0 or more WorkContexts

definedBy

A ActionPerformed is definedBy a ActionDefinition

definedBy

A WFInstance is definedBy a WFDefinition

describedBy

A Experiment is describedBy a ActionProvenanceLog

describedBy

A ActionPerformed is describedBy a ActionDefinition

describedBy

A Service is describedBy a ServiceDescription

performedBy

A ActionPerformed is performedBy a Service

originAction

A DataThing may have originAction a ActionPerformed, that is the DataThing is an output of the ActionPerformed

Input

An ActionPerformed may have (hasInput) 0 or more Input, which have dataThing a DataThing

subscription

A Notification has subscription a Subscription

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-- MarkGreenwood - 19 Feb 2003