container based persistence 1 container based persistence brian berenbach siemens corporate research...

Container Based Persistence 1

Container Based PersistenceContainer Based Persistence

Brian BerenbachBrian BerenbachSiemens Corporate ResearchSiemens Corporate Research

[email protected]@scr.siemens.com


The ProblemThe ProblemDefining the architecture of “Groupware” Defining the architecture of “Groupware”

systems wheresystems where::

multiple are clients supported by a single server, multiple are clients supported by a single server, there is a requirement to notify client objects there is a requirement to notify client objects

whenever something they are viewing or whenever something they are viewing or manipulating has changed in the database,manipulating has changed in the database,

less experienced developers need to extract, less experienced developers need to extract, manipulate, and store objects with no knowledge manipulate, and store objects with no knowledge of the underlying persistence mechanisms andof the underlying persistence mechanisms and

there is coherent persistence of complex there is coherent persistence of complex aggregate objects.aggregate objects.


Problem DomainsProblem Domains

Real time Command and ControlReal time Command and Control Payroll and other HR systemsPayroll and other HR systems Document ManagementDocument Management TradingTrading Software Defect TrackingSoftware Defect Tracking Other “Groupware” applications with 50 or Other “Groupware” applications with 50 or

less simultaneous clientsless simultaneous clients


A Robust Recommended SolutionA Robust Recommended Solution

Let the container manage persistence,Let the container manage persistence,

the container collaborates with an event the container collaborates with an event

management server,management server,

all events are raised by the container andall events are raised by the container and

all persistence complexities are hidden all persistence complexities are hidden

behind the container API.behind the container API.


Let the Container Manage Persistence

CCOONNTTAAIINNEERR

ClientClient ObjectObjectTransferTransfer

StorePersistentPersistent

StoreStore

StorageStorageManagementManagement


Container-Event Management CollaborationContainer-Event Management Collaboration

Container

ApplicationPart Object

ApplicationObjectClient

DatabaseProxy

Event Proxy

Event Server

Database

raiseevent

notifies

uses

notifies

usesmayhave

11 1 1..N 11

represents

1

1..N 1 1..N 1 0..N

Retrieves& stores

Objects from

1

1..N

contains

0..N

1


theEventServertheObjectContaineranObjectForm

anObject

raise ( anObject Changed )

replace ( anObject )

editing changes

anObject

retrieve( anObjectId )

create

populate

show

refresh

retrieve( objectId )

repopulate

anObject

save

objectChangedEvent ( objectId )

Example of Change Event NotificationExample of Change Event Notification


Container DetailsContainer Details

Base Container

add(objItem : Object) : LongcheckForCompleteness(varItem : Variant) : Collectioncopy(objSourceObject : Object, objTargetObject : Object) : Integerdelete(varItemToDelete : Variant) : IntegerisEmpty() : Booleanexists(varItem : Variant) : Booleanexport(strFileName : String) : IntegeridToName(lngObjectId : Long) : StringnameToId(strName : String) : Longrename(strOldname : String, strNewName : String) : Integerreplace(objitem : Object) : Integerretrieve(varItem : Variant) : Object


Persistent Objects can be complexPersistent Objects can be complex

DocumentDocument

NameName

Status : BooleanStatus : Boolean

ImportanceImportance

ConfidentialityConfidentiality

Reference : BooleanReference : Boolean

Sourcereference : StringSourcereference : String

VersionVersion

ValidatefilesValidatefiles

ValidatenameValidatename

Status(Documentstatus)Status(Documentstatus)

{Abstract{Abstract}}

SectionSection

NameName

StatusStatus1+

Contains

Note that a document contains zero or more sections. How to store a document as a coherententity?


The database Id helps manage persistenceThe database Id helps manage persistence

The database Id is used to distinguish between new and existing objects:

Newly Created ObjectId is null

Object That Has Been Retrieved From storageValid Id

On a Save Operation:If the Id is null

perform an INSERT operation

Else

perform an UPDATE operation

End If

Section Key Data

SectionId [PK1]Section.DocumentId [PK2] [FK]

Document Key Data DocumentId [PK1]

may have


Application Developers don’t see this complexityApplication Developers don’t see this complexity

Documents

save()

Document

documentId

save()0..n1

contains

Sections

save(documentId)

1

1has

Section

sectionId

save(documentId)0..n1

contains

Paragraphs

save(sectionId)

1

1has

Paragraph

paragraphId

save(sectionId)0..n1

contains

1

1

0..n1

0..n1

1

1

0..n1

Documents haveSections which have

Paragraphs which have…


Sample Persistence ProcessSample Persistence ProcessContainer.save()

<Code to save my attributes…>For each section in Me.Sections

section.save (Me.Id)Next

Inside a document

For each document in Me.DocumentsBegin Transaction

document.saveCommit

End TransactionNext

Inside the container

<Code to save my attributes…>For each paragraph in Me.Paragraphs

paragraph.save (Me.Id)Next

Inside a section

Container boundary


Sample Application:Groupware Test Construction ToolkitSample Application:Groupware Test Construction Toolkit

TaskTaskDeveloperDeveloper

AssessmentAssessmentAssemblerAssembler

Subject MatterSubject MatterExpertExpert

TestToolkitTest

Toolkit

Licensing & Licensing & EntranceEntranceExamsExams

……Produces


Test Toolkit ExampleTest Toolkit Example

OLE LinkOLE LinkOLE LinkOLE Link


Questions?