SOA for PL/SQL Developer (OPP 2010)

SOA for PL/SQL
Developers
OPP 2010
28th October, 2010
Lucas Jellema
AMIS, The Netherlands
WebLogic Server 11g
SOA Suite 11g

SOA is not…
• XML
• WebService
• SOAP
• Middle Tier or Application Server
• Java
• High level – abstract – architecture
• Unrelated to the database and PL/SQL
• Complex
only/always

SOA =
Business
Agility 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
• Design Time
– Separate teams working in parallel based on mutually
agreed interface definitions
• Technical
– No proprietary technology, protocol, message format
– Standards based (XML, HTTP, RSS, WSDL…)
• Temporal
– Asynchronous communication (separate response)

Objectives (1/2)
• Business Agility
– (Faster) responses to (new and changing) market
demands and user requirements
• IT Flexibility
– Optimize locally without impact ‘globally’
– Prepare for future developments
• Lower costs
– Through reuse, better integration, decoupling,
automation of manual tasks & human coordination

Objectives (2/2)
• (longer term) Higher Quality and Faster
(traceable) Process execution
– Automated data exchange cross boundaries
– Workflow and task orientation
• integrated, cross department, in a controlled way based
on sound understanding of the business processes
– Business Event driven interaction
• Manage risks and fear

Common Characteristics in SOA
• Cross Boundaries
– Cross Technology - .Net, Uniface, Java, Tibco
– Cross Channel – Back Office, Web, PDA, API
– Cross User Group – Internal, Agents, Self Service
– Cross Domain – Multiple departments & systems
– Cross Enterprise – Interact with external partners
• Data synchronization or consolidation
• Management whim Vision
• From Database angle: providing services

What is a service?
• Standards based callable, reusable functionality
according to an interaction contract
• In terms of functionality (WSDL – compare
Package Specification)
– What are the input parameters
– What are the output parameters (if any)
– What are the exceptions
– How (when, where) is the
response delivered
– Implementation is hidden!

What is a service (2)?
• In terms of operational QoS (Quality of Service)
define in a Service Level Agreement (SLA)
– Availability
– Stability & Release schedule
– Response Time
– Peak load capacity
– Price
– Reliability, Confidentiality
– Address, protocol

Services in various shapes
• Library (dll, jar)
• Java Class (public methods) or an EJB
(interface)
• URL
• RSS feed
• Portlet (UI Service)
• SOAP WebService
• Database View or Package Specification
• ….
If it exposes a clear,
standardized interface

Example of a service call?
• Browser sends
http request to a URL
– Text based message
with headers and body

What is a service call?
• Server returns a response
– Another text based
message with headers
and body

Key SOA concepts and lessons
• Functional interface, hiding implementation details
– for example Package specification

Design by Contract
Encapsulation
Decoupling
Assertion

specification
body
Encapsulation

specification
body
specification
body
Decoupling

Contract Specification Assertions

function func ( p_name in varchar2
,p_sal in number
,p_hiredate in date
)
return number

function func ( p_name in varchar2
,p_sal in number
,p_hiredate in date
)
return number
Expectation
regarding Valid Input
Agreed Contract
Indication of possible
Exceptions
Description of
output value

-- Description of this function
--
-- %param p_name Name of an Employee
-- {*} Requirement Name must be provided
--
-- %param p_sal Salary of the Employee
-- {*} Requirement Salary must be greater than zero
--
-- %param p_hiredate Hiredate
-- {*} Requirement Hiredate must be in the Future
--
-- %raises DBC.AssertFail
-- When a Parameter does not match the requirement
--
-- %raises EmployeeNotFound
-- When a an employee with p_name can not be found
--
-- %return
-- The value returned is an integer: 0 < return <= 4

– Simple View API (possibly with IOT) – with complex joins,
analytical functions, advanced SQL and PL/SQL integration
– Package specification

API Services for consumers
• Views – for encapsulation of (legacy) model, multi-table
join, collection integration, SQL hiding (but still SQL)
• PL/SQL – for encapsulation, cursor based data retrieval,
DML hiding, table decoupling (no SQL)
View

Providing a ‘business object’ API
• DML API: can be a View – aided by Instead Of trigger
• Insert of one new row in
USERS_VW can actually
be four new records
– USER, PERSON,
EMAIL_TYPE
EMAIL_ADDRESS
USERS
PERSONS EMAIL_
ADDRESSES
EMAIL_TYPE
USERS
*
* *
*

FIY Data Service API: returning
cursors
• Fetch it Yourself!
• Cursor opened to be fetched from
– Data is gathered and
pre-processed before being returned
– SQL is wrapped
• And can be constructed at run-time
– Access privileges are taken care of
– Cursors can be handled elegantly
in most client languages and technologies
• For example Java: JDBC ResultSet
Prompt
Prompt
Prompt
Prompt
Prompt
Prompt Prompt Prompt Prompt
A
ct
ie
A
ct
ie
HRM_API
CURSOR

Demo
• Create a database “service”
– for retrieving a department, its employees and the
manager for each employee
– that is promotes decoupling and encapsulates
implementation
– that can be extended to also support
data manipulation
• Leveraging Types and Collections
to support nested structures
such as master-details DEPT EMP
DEPARTMENTS
HRM
Service
API
SQL
PL/
SQL
•Cursor
•Collection
•XML

– Package specification
– View API
• Reusable, standardized services as flexible building
blocks
• Aggregate and Combine into more valuable reusables
• Governance: security, management of services, SLAs
– Allow for configuration without development or
deployment effort
• Decoupling in every aspect!

Coupling & Decoupling in Oracle RDBMS
Decoupling
• Package Specification
• Views (+ Instead of Trigger)
• Triggers in general
• DBMS_JOB
• Advanced Queuing
• Publish (intranet) XML
& WebService
• %TYPE instead of hardcoded
data type
• Centrally managed
“parameter (injection) service”
– instead of local constants
– instead of hard coded values
• Use generic (SOA) services
Coupling
• Database Link
• SYSDATE and USER
• Application performing SQL
against tables
– SQL all over the place
• Access database from DMZ or
even outside firewall
– Publish WebService or Web
Application on Internet
• Too frequent use of
dbms_output.put_line
• Copy and paste of code
• Poorly documented code
• Use of exotic features
summary

Decoupling Applications & Data
Data
Application
(User Interface)
Application
(User Interface)
Data

Application
(User Interface)
Data
Application
(User Interface)

(User Interface) Application
Workflow
Engine
Email
IM
Fax
CMS

‘formal’ SOA infrastructure

Enterprise Service Bus
Data
Service Service Service
App 2
Data
Service
External
Partner
Service
App 1

The Enterprise Service Bus
• Should first of all be considered ‘a pattern’
• Virtualizes services – hides the real service from
consumers
– Deals with the physical location of the services
– Interacts with the technology used to implement services
• Adapts synchronous to a-synchronous and vv.
• Can use multiple real services to offer one virtual
(composite) service
• 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”

Canonical Data Model
• Common Business Language
– Esperanto for service invokers
Data
Data
ServiceService
Clients
Customers

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

Tables & Business Rules
Views
PL/SQL “Services”
Oracle
Forms
Forms
DWH
External Partners
Web Application
Email
Server
Java based
SQL*
Loader
Modern Architecture
and the role of the database

Tables & Business Rules
Views
PL/SQL “Services”
Oracle
Forms
Forms
External Partners
Web Application
Email
Server
Java based
(extranet)
Web Application
Internal Users
(outside
intranet/firewall)
“Mobile
Enabled”
ADF 11g
ADF 11g
Enterprise Service and Process Bus
(SOA Suite 11g: BPEL, Mediator,
Human Task, Business Rules, Technology Adapters)
files
UCM
(Document
Management)
DWH
Operational
Dashboard
APEX

The SOA Suite 11g
• The engine that
– runs applications that implement the WebServices
– implements the Enterprise Service Bus [pattern]
– Lives inside the WebLogic Server application server
WebLogic Server 11g
SOA Suite 11g
WebServices

SOA Suite 11g Composite
Applications
• SOA Composite Applications consist of special
components that process XML messages:
– Decision Logic (go left or right, discount is X)
– Human Workflow
(end user must act)
– BPEL (service
orchestration)
– Mediator (filter,
transform and route
messages)

SOA Suite 11g – calling out to
external service and adapters
• SOA Composite Applications can call out to external
WebServices and Adapters
• Adapters connect to various technologies
– Database
(SQL & PL/SQL)
– Advanced Queuing
– File & FTP
– JMS, MQ Series, EBS
TCP/IP Sockets
• Adapters can trigger
application execution

Publish Services from the Database
• Describe Services in WSDL and XSL
– Specify operations, input and output parameters
– Describe complex data structures of
parameters
• Publish Database-based Services
– Plain URL services through PL/SQL packages
• based on MOD_PLSQL, XML DB or DBMS_EPG
– Full blown SOAP WebServices
• 11g Native WebService (publish PL/SQL package), use
UTL_DBWS, JPublisher for Java proxy class in AppServer
– Leverage SOA Suite to expose Database functionality
• Through the database adapter in SOA Suite/WLS

#1 SOA task: Publish PL/SQL
Package through ESB
• Use Database Adapter to create
Service, combine with ESB Routing Service
• Use case:
– external access to services
– virtualize location and technology 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*

Demo
• Create SOA Composite application
• Configure Database Adapter to interact with
HRM_SERVICE_API package
• Create a Mediator to transform XML message
from the db adapter to the desired format

Demo
• Create SOA Composite application
• Configure Database Adapter to interact with
HRM_SERVICE_API package
• Create a Mediator to transform XML message
from the db adapter to the desired format
• Deploy SOA Composite in SOA Suite in WLS
• Test the Web Service based on the PL/SQL
package based on the DEPT and EMP table

SOA Composite Application
exposes Hrm Web Service

Enterprise Service Bus
in action
• One team responsible for exposing
services to external consumers
– Working with those customers for establishing the
contract and testing across the firewall
– This team built from internally provided services
• Team two worked inside database – providing
package based API for granular services
• Team three created ESB level database
adapter and routing/mapping services
WS*

Business Events
Dealer
Order
Event
Pool
Sales Desk
Marketing
Customer Relations
Shipping

Event Driven Architecture
• EDA (is also Extremely 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

Leveraging SOA Suite 11g
from the database
• The database can call out to the SOA Suite 11g
– With UTL_HTTP or Stored Java (2-way,
synchronous)
– Through Advanced Queuing or Database Adapter
polling (one way)
WebLogic Server 11g
SOA Suite 11g AQ
AQ

Call the “getOilPrice Service”
• We need to know the oil price
for some calculations…
• But that price is not constant,
we need the current price
•
• We do not want the
exact market price, we have
our own contracts
• Let’s define a constant in a
package
• Oh, well, let’s call a
WebService – Yahoo?
• Ah, the Purchasing
department publishes a
WebService for such data

Calling a Web Service
• Send an XML document to a URL via HTTP
– Request message contains headers and body
• Service (server) returns another XML document
– Response message contains headers and body
• Response can be a fault (a WebService exception)
• Headers are used for meta-data
– Sender (identity, address), Return address
– Encryption, digitally signed,
– Type of content, type of compression

PurchasingPrices available via SOAP
• PurchasingPrices Service is available as a (SOAP
based) WebService (implemented using BPEL)
– Service and WSDL are available (URLs are known)

• SOAP call over HTTP can be made from PL/SQL
– Using UTL_HTTP
• Assemble SOAP message
– Envelope
– Payload
• Name of product
– Make HTTP Post request
– Process Response
• Retrieve and Return the product price
– “re-Publish” service as PL/SQL function
WebLogic Server 11g
SOA Suite 11g

WebLogic Server 11g
SOA Suite 11g

Publishing events to the EDN
from within the database
• Publishing events to the Event Delivery Network
from table triggers or PL/SQL APIs
– Is best done via Advanced Queuing
• The same route in reverse can consume events from
EDN into the database

The database can ask the middle
tier for other services as well
• Get information from (or to) services on the intranet
or internet (‘please get us the NBA scores ’)
• Publish/Send information to the internet
(RSS, email, chat)
• Can tell the middle tier
– Interesting events
and data changes
• Trigger cache refresh!
– Alert about (im)pending issues,
attempted rule violations, …
– The outcome of batch calculcations
WebLogic Server 11g
SOA Suite 11g
AQ
Web App
summary

Complex Event Processing
to process on behalf of database
events
JMS
HTTP
JMX
File
DB
Complex Event
Processor
Event
Consumer
Alert
JMS
Dashboard
SOA Application
DB
Data Warehouse
WebService
File

The Data Avalanche
• The league of real time events
– Continuous stream of a multitude of tiny events with
hardly any payload, most of which are not interesting at all
– Sent from physical sensors (temperature, pressure, RFID,
security gates), process sensors, Twitter, manufacturing
equipment, database triggers, web servers, ESBs, stock
trade tickers, sport statistics, RSS, network switches, …

Making Sense of Non-sense
Complex Event Processing
• Useful information could be hidden in those streams
of events – and CEP extracts it
– By detecting patterns, deviations, aggregations in these
event streams
– CEP publishes ‘meaningful’ (business) events to report its
findings – by executing some Event Processing Langugae
events
Complex Event
Processor

Continuous Query Language (CQL)
• Standard extension/complement to SQL
– For handling large volumes of continuously arriving events
– Executing the queries continuously
• Operates on streams of continually arriving events
instead of static relational data sets
– Events can be enriched with context
– Results keep being produced as event stream
• Is used for comparing events of same type, to find
– Trends and Patterns
– Exceptions
– Aggregates
Complex Event
Processor
summary

Business Agility through
Decoupling

PL/SQL Package
PL/SQL Package
PL/SQL Package
PL/SQL Package
PL/SQL Package

True Injection
Dependency_Injector
After Logon
trigger
setMailServer
EMAILER
setInterestRate
setVatRate
TAX_CALC
setFileInName
setLogLevel
LOGGER
setUrlProxy
RSS_READER
Configuration Values
mailserver
interest_rate
vat_rate
file_in_name
log_level
url_proxy
emailer
tax_calc
tax_calc
logger
logger
rss_reader
amislin32
4.5
17.6
app_log_x
debug
amisvm2…
property package value

Decoupling from Table to ESB+
http
WEBDAVFTP
http
WS/SOAP
WS*
WS*
WS*
WSRP
coupled
complex

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

Summary
• SOA is about decoupling, integration & reuse
• SOA Suite 11g runs service implementations
– That can access database and other technologies
through adapters – either inbound or outbound
• Database can access services from utl_http
– Or AQ, Database polling or File polling
• SOA Suite hooks into database via SQL,
PL/SQL, AQ or even XML DB file protocols
• Many SOA concepts can be applied without
the SOA Suite, using standard DB features

Resources
• Presentation and demos are on our blog
– http://technology.amis.nl/blog
• Contact me at:
– lucas.jellema@
amis.nl

SOA for PL/SQL Developer (OPP 2010)

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