The Story of How an Oracle Classic Stronghold successfully embraced SOA

16th June 2009 The Story of How an Oracle Classic Stronghold Successfully Embraced SOA 1

The Story of How an Oracle Classic Stronghold Successfully

Embraced SOA

AMIS ODTUG Preview15th June 2009Lucas JellemaSOA


Overview• What is an Oracle stronghold?• Triggers to start moving towards Services• Levels of embracing Services and SOA

– Objectives, benefits, costs & challenges– Demonstration

• Pitfalls, Lessons Learned & Best Practices• Summary


What is an Oracle stronghold?• The typical Oracle stronghold

– Using Oracle RDBMS & Oracle Development tools• Lot of SQL and PL/SQL• Probably Oracle Forms and maybe APEX as well• Possibly Oracle Designer, tools for BI & Reporting

– Several databases with many years of essential corporate data

– IT staff has Oracle veterans – 5-15 years or more– Internet development may have taken place largely

separate from the Oracle technology stack


Then wat happened…• Job Agency offered Oracle Forms application

for entering timesheets– Business partners requested a programmatic

interface to load multiple timesheets– Marketing wants to expose job details from the

back office through an internet website

• Oracle Forms application for assigning homes offered SaaS-style– SaaS Customers want the details on houses and

their availability published on a website


Then wat happened… (2)• Car Lease company has various custom

applications and databases per department– Business requires IT to support processes that go

across those applications and databases• through a single, unified User Interface• involving a legacy database and a 3rd party ERP system• with eventually some self service web modules

• Insurance company sells policies through agents using a Forms application– New direct channel: On-line policy selling


Then wat happened… (3)• Agricultural company supports ‘cow

insemination’ process with Forms application– Farmers and inspectors need to be able to record

data anytime and anywhere through PDAs (that run a .Net application)

• Mid-sized chemical pharmaceutical company uses BoB stand-alone systems and databases– To allow for faster (near real-time) responses to

customer demands and logistical challenges, tighter integration between the systems is needed


Common Characteristics


Objectives• Business Agility

– (Faster) responses to changing demands– Creating new business from existing resources

• Lower costs– Through reuse, better integration, decoupling

• Higher Quality and Faster Process execution– Automated data exchange cross boundaries– Workflow and task orientation– Business Event driven interaction


SOA = BAD


SOA =BusinessAgility through

Decoupling


Decoupling≈

Managing Dependencies

minimize impact of change while maximizing reusability


Types of decoupling• Functional

– Interface - Encapsulation of implementation• Design by Contract, Implement by Design

• Technical– No proprietary technology, protocol, message format– Standards based (XML, HTTP, RSS, WSDL…)

• Temporal– Asynchronous communication (separate response)

• Development– Separate teams working in parallel based on mutually

agreed interface definitions


Decoupling Applications & Data

Data

Application(User Interface)


Data




Data




(User Interface)

Data

Application


Decoupling Applications & Data(User Interface) Application

WorkflowEngine

EmailIM

Fax

CMS


Data Ownership• Data no longer exclusively owned by a single

application• Data (query and manipulation) available via APIs,

(web)services and open standards– For example based on XML, XSD, WSDL, SOAP, HTTP

• Data Hubs are formalized, structured approach where data is completely separated from applications– All access is through services– No data duplication at all in the enterprise– Data ownership is separate process


Decoupling from Table to ESB+

http

WEBDAVFTP

http

WS/SOAP

WS*

WS*

WS*

WSRP


Tables in Database• SQL for retrieval and manipulation• Data Model in plain “view”• Decoupling between DML and Retrieval• select e.empno, e.ename

, d.dname from emp join dept using (deptno)

• Insert into dept;insert into emp;


View in Database• Hide (encapsulate) Data Model

– Manage access privileges

• SQL for retrieval and manipulation• Instead Of trigger decouples DML operations• select id, name, department from emp_vw• Insert into emp_vw• Use case: new UI on top of ‘legacy’ data

model


Package in Database• Hide (encapsulate) SQL• Procedure calls for retrieval and manipulation

– Potentially complex data structures using Object Types and (nested) Cursors

• HRM_MGR.get_emp( id) return emp_t• HRM_MGR.create_emp( emp_t);• Use case: tailor made business services to

support (Java) client


Package in Database (2)• Hide (encapsulate) SQL and Oracle

and user defined Types • Procedure calls for retrieval and manipulation

– Input and output parameters standard types only (string and number)

– Complex datastructures: XML passed as string• HRM_MGR.get_emp( id) return string• HRM_MGR.create_emp( string);• Use case: packaged business services to

support any client (that can access the DB)


Handling XML• Structured, multi-level data in a string: XML• Oracle Database has XMLType

– Can be created from a String, will parse XML• Can validate against a schema definition (the XML data

design)

– Support XPath operations to retrieve specific bits and pieces from the XML document

– Can do XSLT transformations of the incoming or outgoing XML


AQ for Asynchronous• Decouple consumer and provider

in time – asynchronuous processing• Consumer is registered on the AQ

– Usually a package that processes User Defined Type that is sent as payload in the AQ message

• Use case: asynchronously processed one-way (fire-n-forget) requests– Potentially lenghty requests– High volume of requests


Hiding the database

http

WEBDAVFTP

http

WS/SOAP

WS*

WS*

WS*


Publish package as http-based API using dbms_epg

• Hide database protocol– Not its physical location nor the schema, and user

authentication

• HTTP communication is truly cross technology– Browser, Java, .Net, JavaScript & RIA clients, …– Approximation of RESTful services (very du jour)

• Can publish in various formats– Text, HTML, CSV, JSON, XML, RSS

• Use case:cross-technology, internal no WS*/ESB

http


Publish static resources on various protocols with XMLDB

• Hide database protocol– support FTP, WEBDAV, HTTP(S)

• Run scheduled batch jobs (PL/SQL) to periodically create & expose resources– Can also consume and process resources

• Use case: cross technology need for retrieving slowly changing resources (CSV, XML)– Possibly uploading resources for batch processing

• Use case:

WEBDAV

FTP

http


SOAP based WebServices

http

WEBDAVFTP

http

WS/SOAP

WS*

WS*

WS*

WSRP


SOAP WebServices• All messages (input and output) are XML• The message consists of two parts inside an

envelope (a SOAP XML wrapper)– The header with meta-data– The body with the contents to be handled by or

returned by the service• The WebService Definition Language (WSDL)

document describes the service• An XML Schema Document (XSD) describes

the structure of the XML messages– XSD is like an ERD or Table Design


Oracle RDBMS 11g - Native Database WebServices

• Schema can be published throughnative database web services– Each package corresponds with a WSDL– Every program unit with an operation– WSDL and XSD are dynamically generated

WS/SOAP

– http and https is supported– Limited control over WSDL & XSD

– Use case: internal, cross technology, WS enabled client, no ESB or Application Server available


WebService in App Server based on PL/SQL package

• Hide database– Protocol, location, authentication:

everything handled by the application server• Use JPublisher (embedded in JDeveloper) to

publish a PL/SQL package as WebService– JPublisher creates JAX-WS-annotated class, utility

classes and possibly helper types in the database• Alternatively: create ADF BC Application

Module & publish it as a WebService (Bulldog)– With support for SDO (Service Data Objects)

• Use case: WS (SDO!) enabled client, no ESB

WS*


Enterprise Service Bus

Data

Service Service Service

App 2

Data

Service

External Partner

Service

App 1


The Enterprise Service Bus• Virtualizes services – hides the real service

from consumers– Deals with the physical location of the services

• Allows callers to use a generic, canonical message structure that it will transform to the service contract– It may even allow callers to use their own “lingo”

• Adapts synchronous to a-synchronous and vv.• Can use multiple real services to offer one

virtual (composite) service


The Enterprise Service Bus (2)• Handles various QoS & SLA aspects

– sometimes in concert with tools like OWSM– Encryption, signing, authentication– Retry and fallback– “Throttle” (prevent peak loads)

• Does monitoring, tracking & auditing, reporting, notification and escalation

• Works with Adapters to access technologies– like RDBMS (SQL, PL/SQL), AQ and JMS, File

System, FTP, Java, E-Business Suite


Publish PL/SQL Package through ESB

• Use Database Adapter to createService, combine with ESB Routing Service

• Use case: – external access to services– virtualize location of service –

• route to service based on content of the request

– virtualize part of contract of service• Package-derived XSD not suitable for consumers

– handle peak loads– monitor service levels and trace service access

WS*


Introducing BPEL for Service• BPEL adds to service

– Long running (stateful) ‘service instances’– Composite services that include

• Multiple service calls (including asynchronous)• Exception handling including retry and compensation• Human Task for manual steps & Integration Rule Engine• Process flow logic

• Use case: – data request must be fulfilled by various services;– dml impacts several systems and/or requires

human approval

WS*


Publish Business Events• Extreme Decoupled Architecture• Any system – including database – reports

events that may be interesting to other parties• The Event backbone (could be the ESB)

– Defines Event Types (name, structure of payload)– Registers Event Listeners (“please call me when the

event occurs and send the details”)– Receives events – instances of the predefined event

type with payload and timestamp• Propagate events to all registered listeners• Without blocking the event producer


Event Driven Architecture (EDA)

Data

Service Service Service

App 2

Data

Service

External Partner

Service

App 1


Database publishing events• Table Trigger intercepts DML

– Checks for Business Events such as new employee– Sends them to package EVENT_PRODUCER

• Package EVENT_PRODUCER sends events– Via UTL_HTTP to a WebService– Via AQ to a listener (ESB AQ Adapter)

WS*

EventProducerEMP


Publishing Service with UI• Instead of only publishing a

programmatic service interface– A service can be published with a User Interface;

the service-with-UI is called: Portlet

• The standard approach:– Portlet Container in Application Server exposes

WSRP services for the portlets– The Portlet produces (X)HTML and handles HTTP

requests– A Portal consumes the WSRP Portlets in a web page

WSRP


Decoupling from Table to ESB+

http

WEBDAVFTP

http

WS/SOAP

WS*

WS*

WS*

WSRP


Increasingly decoupled• More hiding of the implementation• More Formal Interface Contract• Less (proprietary) technology & more standards

for interacting• Less exposure of (legacy) data model• More support for asynchronous interaction• More reuse potential• Pervasive throughout enterprise• More suitable for external consumption


Comes at a cost…• More run time overhead

– Additional tiers– XML serialization and deserialization

• More infrastructure– Burden of Administration– License Costs– Hardware

• Broader skills palette – more stuff to master• Harder to get started


Pitfalls• Inconsistent, illegible, unstructured

namespaces and (XML) data model– Having the database (table and column names)

shine through in the canonical data model

• Introducing new unmanaged dependencies– Hard coded endpoints (service URLs)– Calling external services without proper SLA or

fallback option– Using complex technology without proper skills


Pitfalls• Lack of Balance between reusability and

usefulness (Fine grained vs. coarse grained)• The greedy clutches of enterprise architects

– Think, talk, (high level) design, draw & write, present, think, talk, …. (no real action)

• Inappropriate use of the SOA infrastructure– Web applications retrieving each indivual record (or

even field) through a separate service call• Running Forms on top of the ESB!

– Sending debug and trace messages via the ESB– Package calls other package via ESB


Pay close attention to…• Handling errors, exceptions, time out etc.

– Early detection of service unavailability

• SOA and Services Governance– Involve business in managing services and

canonical data model– Implement process of life cycle management– Ensure services are well known, findable & trusted

• Involving DBAs/Administrators early on• Implementing DTAP process & environment


Useful • Publish actual XSDs very visibly• Use Mock Service implementations during

development and test• Automated Functional and Performance Test

of individual Services• Automatic Service ‘ping’ utility• Quality of Service – SLAs and Monitoring• Canonical Model also includes Domains,

Dictionary and “Identity Repository”


Summary• Objective: agility through decoupling

– Managing dependencies– Crossing boundaries – functional, technology, time

• Just do it!– Get started – at the right level for your situation

• Do not go off and buy BPEL just like that

– Even though it won’t be perfect the first time round – you will learn (only) through experience

• Do it explicitly, visibly and with all involved

SOA

The Story of How an Oracle Classic Stronghold successfully embraced SOA

Documents

data ownership data

data duplication

manipulation data model

emp emp

single application data

http data hubs

legacy data model

complex data structures