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How PL/SQL Applications Can Participate in a Service-Oriented Architecture

Aino Andriessen

AMIS

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SOA PartyPL/SQL

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SOA

design connectivity

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Service Design

Focus on function a service is not a technical solution

Component vs. service

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Examples

zipcode check / address check notification service converter

xx -> xml currency

CD information lookup

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Connectivity

any technology standards

XML http soap ws-... ...

synchronous vs. a-synchronous a service is not necessarily a webservice Loosely-coupled

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The position of the database

Traditionally, the database could be considered as an isolated entity, only available to its application(s).

Forms

db

VB webapp

internet intranet

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The position of the database - 2

Nowadays, the (Oracle) database is able to function on its own and to deliver applications / services without the need

of an application server to connect directly to other applications / services use on standard internet technology synchronous and a-synchronous

db

internet intranet

appB

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PL/SQL applications can function as a service provider and as a service consumer.

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Database access (provider)

Oracle Database

JDBC

SQL*NET

ODBCWEBDAV

FTP

HTTP

XMLDB webserver

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Access the outside world (consumer)

Oracle Database

files

host

Database linkHTTP

External procedure

mail

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This sheet has been left blank on purpose

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Webservices

According to the W3C a Web service is a software system designed to support interoperable machine-to-machine interaction over a network

(in general) synchronous Request - Response mechanism

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Web service protocol stack

Service transport http, smtp, ftp, ...

XML messaging soap, rest, xml-rpc, ...

Service description wsdl

Service discovery uddi

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SOAP example

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">

<soap:Header>...</soap:Header>

<soap:Body>

<getProductDetails xmlns="http://warehouse.example.com/ws">

<productID>827635</productID>

</getProductDetails>

</soap:Body>

</soap:Envelope>

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">

<soap:Body>

<getProductDetailsResponse xmlns="http://warehouse.example.com/ws">

<getProductDetailsResult>

<productName>Toptimate 3-Piece Set</productName>

<productID>827635</productID>

<description>3-Piece luggage set. Black Polyester.</description>

<price>96.50</price>

<inStock>true</inStock>

</getProductDetailsResult>

</getProductDetailsResponse>

</soap:Body>

</soap:Envelope>

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PL/SQL as a Webservice consumer

PL/SQL

Webservice

utl_http / utl_dbws

http

Java stored procedure

Webservice

http

PL/SQL wrapper

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Demo

utl_http

Webservice

utl_dbws

wsdl

ws_odtug_service_client.pkb

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Webservice producer

PL/SQL

consumer

http

XMLDB webserver

mod_plsql

PL/SQL

consumer

http

Application ServerWebapp

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Demo

ws_server.conferences

Browser

http

XMLDB webserver

/ws

DBMS_EPG.create_dad (

dad_name => 'ws',

path => '/ws/*');

ws_server.pkb

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Messaging

a-synchronous transportlayer - MOM

Tibco, IBM MQ, JMS, AQ, ...

some standarization JMS interface SOAP message format

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Messaging concepts

queue / topic enqueue - dequeue point - to - point publish - subscribe

producer queue consumerenqueue dequeue

producerqueue / topic

consumerpublish

consumer

subscribe

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Oracle Streams Advanced Queuing (AQ)

queue queue table (or memory) exception queue queue view payload subscriber propagation

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AQ

API : dbms_aqadm dbms_aq ! Never, ever perform direct dml on queue tables

payload = message type: object

• oracle objects, xmltype, collections

varchar2 raw

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Access

PL/SQL java / JMS / jdbc

oracle.jms, javax.jms VB

Oracle objects for OLE

OCI Internet Oracle Messaging Gateway

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AQ Internet access

You can access Oracle Streams AQ over the Internet by using Simple Object Access Protocol (SOAP). Internet Data Access Presentation (IDAP) defines

the XML message structure for the body of the SOAP request.

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Oracle Messaging Gateway

Messaging Gateway enables communication between applications based on non-Oracle messaging systems and Oracle Streams AQ.

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AQ implementation

Oracle products interconnect ...

ESB / integration products Mule Oracle ESB iWay BEA ...

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Demo

B.Developer

A.Conference Registration

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JDBC

B.Developer

A.Conference Registration

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make_registrationreceive_confirmation

receive_registrationsend_confirmation

Mule - ESB

Developer2

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Developer2

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Command Line Command Line

do_enqueue.prc

do_dequeue.fncDeveloper.java

aq_send.xml

aq_receive.xml

Developer2.java

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Conclusion

PL/SQL can interact directly with the world outside the database, using standard 'internet' technology, either directly or via Oracle messaging (AQ).

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!

SOA Party

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Questions & Answers

aino.andriessen@amis.nl

AMIS weblog : http://technology.amis.nl/blog/