REACHING OUT FROM PL/SQL

Lucas Jellema – AMIS (Nieuwegein, The Netherlands)

Oracle Open World 2011

ASK WHAT YOU CAN DO FOR YOUR COUNTRY?!

Do not ask what your country can do for you

AND ALSO ASK WHAT YOU (THROUGH PL/SQL & THE DATABASE) CAN DO FOR YOUR “ENVIRONMENT”?!

By all means, ask what the world around you can mean for your PL/SQL application

Database(SQL & PL/SQL)

Database(SQL & PL/SQL)

SOA

Database(SQL & PL/SQL)

Email

User Interface

Chat (IM)

File (Excel, PDF,…)

RSS

Queue

REST

WebService

File, O/S

JDBC, SQL Net, DB Link

THE HUMAN SIDE OF THINGS

EMP

CHALLENGES

EMP

Q

Mail Server

receiveMailsendEmail

JSP_WRAPPER

Job

EMAILS

retrieve_emails

`

AQ

notify_email_event

Process_email

EMP

JAVA STORED PROCEDURES

• Java Classes can be loaded into Oracle Database as Java Stored Procedures

• The “JSPs” are wrapped with a PL/SQL wrapper– When invoked no different from normal PL/SQL units

• JSPs are in same session and transaction• JSPs are static• Java Stored Procedures can complement

PL/SQL– for example in dealings with O/S, Mail Server,

Application Server, IM Server, TCP/IP, Embedded, Devices

• JMX is exposed by Java-in-Database to monitor

JAVA STORED PROCEDURES – JAVA BEHIND PL/SQL WRAPPER

1• Write Functional Java

2• Wrap with PL/SQL

3• Load into Database

4• Set appropriate Privs

5• Invoke JSP via PL/SQL Interface

THE ULTIMATE OUTREACH…

OTHER SCENARIO WITH DATABASE AS INITIATOR OF THE DIALOG• An Update of an Employee’s Salary takes

place• After Update Row level trigger fires

– creates job to send out an email to have someone approve the salary raise

– Sets the status of the salary to ‘awaiting approval’

• Email is sent to approver• Approvers sends an answer

– Decision and comments

• Answer is received & processed by database– Status of salary record is updated

EJB

JMS

Email

Libraries for:• Graphical Manipulation• Translation, • Calculation,• Encryption,• …

CommunicationProtocols: http, ftp, tcp ip, sms, grid, JDBC, JDBC-ODBC, .Net, …

Operating System& File System

dbms_epg(mod_plsql)

http

XMLDB

httpftp

webdav

utl_mailutl_fileexternal

table

APEX

THE ULTIMATE DATABASE USER INTERFACE

dbms_epg(mod_plsql)

DATABASE REACHING OUT TO HUMAN PARTNERS• DBMS_EPG (or good old mod_plsql)

– Expose HTML and RSS & Process HTTP requests

• XMLDB– Expose and allow manipulation of resources

through HTTP, FTP and WEBDAV

• Stored Java Procedures to– Interact with Mail Server, Chat; leverage – Process human file formats (PDF, Excel, images,

…)

• Supplied packages: UTL_MAIL, UTL_FILE

EXPOSE STORED PROCEDURES VIA HTTP• Stored Procedures and Packages can be

configured to handle HTTP requests– Using the supplied DBMS_EPG package

• They compose the HTTP response by writing strings to the HTP.P procedure– Or return binary documents using wpg_docload

• Database infrastructure handles HTTP communication – including security, headers, get/post parameters

• Embedded PLSQL Gateway – powering– APEX and other PL/SQL based HTML UI– Expose RESTful Web Services– Publish RSS Feeds– Asynchronous HTTP notifications

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, …

• Is also possibly remote, across networks, firewalls etc. – easier than normal JDBC connections

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

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

http

SIMPLE DBMS_EPG EXAMPLE

sys

scott

scott

MACHINATIONS

CALL FOR DECOUPLING

• Minimize dependencies and maximize interoperability and reuse

• Through decoupling:– Encapsulate functionality, legacy and

complexity– Interact through well defined interfaces– Support standard protocols and cross

technology facilities (XML, HTTP, JSON, SQL)– Leverage asynchronous exchange whenever

relevant• Take care of the data(base)

– ‘No SQL’ approach: SQL is encapsulated inside database API (View and Package)

– SQL is not left to application developers or 3rd party frameworks

– Data integrity is enforced inside the database

EXTREME ENCAPSULATION

• View on top of table(collection)– With instead of trigger handling DML

– Data queried from NUMBERS is produced in PL/SQL – no underlying table involved

– Data manipulated in NUMBERS is processed in memory

View Numbers

Package P

EXTREME ENCAPSULATION

Database(SQL & PL/SQL)

EmailChat (IM) RSS

Queue

REST

WebService

File, O/S

JDBC, SQL Net, DB Link

dbms_epg(mod_plsql)

http

XMLDB

httpftp

webdav

utl_mailutl_fileexternal

table

utl_http(httpuritype)

http

JDBC/ODBCOCI, DB Link

utl_tcp

AdvancedQueuing

AQjms

nativedbws

Chat/IM XMPP Server

HTTP

JDBC

Other(Email, FTP/File,

XMPP/Chat)

SOA Suite

Oracle Service

Bus

DB

AQ

JMS

EJB

FileFTP

SDO

WS

http

PL/SQL package

Table

AQ

Native DB WebService

EPG

View

WebLogic Server Database

JAX-WS

ADF BC/SDO WS

EJB/JPA

Email ServerFile/FTP Server

UMS

XMLDB

XMLTypes

XMLXML & XSD

JSON/ CSV

Ref Cursor

Types & CollJPublisher

WS

utl_file, BFILE,

URITYPE

JMS Queue

XMLRelational/Oracle Type

BE A GOOD HOST

• Provide services– Views for easy querying– Stored Procedure based APIs

• For data retrieval and data manipulation

– Queues as way-in (publish) as well as way-out (allow subscription) for events

– Send change notifications• Http based push messages• Query Result Change Notification

THE SUPER HOST

Query Result Change Notification

QUERY RESULT CHANGE NOTIFICATION• Continuous Query Notification:

– Send an event when the result set for a query changes

– Background process calls PL/SQL Handler or Java Listener or OCI client when thecommit has occurred

– Event contains rowidof changed rows

• Used for:– Refreshing specific

data caches (middletier, global context)

– (custom) Replication

PL/SQL

Java Listener

DATABASE TO MIDDLE TIER TO CLIENT NOTIFICATION THROUGH HTTP

Application Scope event handler

HTTP

Proce-dure

UTL_HTTP

servlet

Session cache

EMP

servlet1

2

3 45

6

7

8

9A

D

B

C

Job

CROSS TIER PUSH

Web Browser

RDBMS

JEE Application Server

trg

job

servletevt lsnr

MORE INTERACTION FROM & TO THE DATABASE• Files into the database• Database to leverage O/S• Stored Java for non-human interactions• WebServices – publish and consume• Engage Middle Tier as ‘agent’

THE BROWSER IN YOUR DATABASEINTRODUCING UTL_HTTP

≈select utl_http.request ( 'http://technology.amis.nl/blog/?feed=rss2' , null )from dual

THE DATABASE CAN ASK THE MIDDLE TIER TO ACCESS AND PROVIDE SERVICES

• Get information from (or to) services on the intranet or internet

• Publish/Send information to the internet (RSS, email, chat)

• Can tell the middle tier– Interesting events – Alert about

(im)pending issues, attempted rule violations, …

– The outcome of batch calculations

• DB vs. Middle Tier:Security, Functionality, Load Balance

WebLogic Server 11g

SOA Suite 11g

AQ

Web App

HAPPY CHATTING – IM FROM THE DATABASE• Database can call a middle

tier service using utl_httpor HTTPURITYPE– Passing in the destination

and the message content• This Service sends it

onwards to the Google Talk Server WebLogic Server 11g

Service

CHAT_MGR

Service

DATABASE ACTIVELY INFORMS ON EVENTS

WebLogic Server 11g

Service

CHAT_MGR

Service

EMP

CHAT MANAGER PACKAGEcreate or replace package body chat_mgras

c_im_destination CONSTANT varchar2(100):= 'im_account'; c_im_service_base_url CONSTANT varchar2(100):= 'http://host/service?'; c_amp constant varchar2(5) := chr(38);

procedure send_im_message( p_msg in varchar2) is l_response varchar2(32000);begin l_response:= utl_http.request ( c_im_service_base_url ||'imDestination='||c_im_destination ||c_amp||'msgBody='||replace(p_msg,' ', '%20') , null );end send_im_message;

end chat_mgr;

EMP INFORMERcreate or replace trigger mananager_sal_update_watcherbefore insert or update of salon empfor each rowwhen (new.job ='MANAGER' and new.sal > 4000 and new.sal > nvl(old.sal,0))declare l_msg varchar2(32000);begin l_msg:= 'Selfenrichment ' ||'Salary of '||:new.ename ||' ( manager in Department '||:new.deptno||') ' ||'is changed to '||:new.sal ; chat_mgr.send_im_message ( p_msg => l_msg );end;

THE TALKING DATABASE

Details on the Employee. Employee name is Smith, his job is Analyst. He

works in department 20…

EMP

THE TALKING DATABASE

PL/SQLexposed through dbms_epg

httpaudio/mpeg, binary data

RESTFUL WEBSERVICES

• Simple, stateless, light weight, http-based message exchange protocol– Use standard get, put, post, delete operations– Use URL to pass resource reference

• Small, easy-to-understand messages• Typically XML or JSON based• Not using SOAP, or the WS*-stack• Often used directly from User Interface –

(AJAX enabled) JavaScript– RESTful services are primary communication

mechanism for Mobile Apps

RESTFUL ARCHITECTURE

RESTful PL/SQL APIexposed through dbms_epg

httphttp

RESTFUL RESOURCE NAVIGATION

PUBLISH REST-FUL HTTP API – DIRECTLY ON TOP OF THE RDBMS

PUBLISH REST-FUL HTTP API – DIRECTLY ON TOP OF THE RDBMS

CONSUMING REST-FUL SERVICES

• Invoking a REST-ful service is simply making an HTTP request to some URL

• Can be done through:– utl_http– httpuritype– Stored Java

• Result can be processed as just a string or as XML, JSON or other format– OSS Libraries can help with special formats, for

example PL/JSON for JSON

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

CALLING ‘FORMAL’ WS* ANDSOAP BASED WEB SERVICES• Invoking a SOAP WS* service is making an

HTTP request to some URL• Can be done through:

– utl_http– Stored Java– utl_dbws

• Request and Responseare both SOAP-wrapped XML messages– Using XMLDB

functionality including XML Type these can easily by composed, transformed, validated and parsed

ORACLE RDBMS 11G – NATIVE DATABASE WEBSERVICES• Database Schema can be published through

native database web services– Each package corresponds with a WSDL

• With an operation for each Procedure or Function• Auto-mapping from PL/SQL input and output

parameters to WSDL (XSD) Types

– WSDL and XSD are dynamically generated– A generic Query Service (across schema) is

exposed• To execute user defined queries• With support for pagination and some formatting

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

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

SUMMARY

SESSION PLUGGING

• Sunday – Gold Nuggets in ADF (S32502)3.15-4.15, Moscone West-2000

• Tuesday – Reaching Out from PL/SQL (S08625 )10.15-11.15, Mariott Marquis, Salon 7

• Tuesday – (JavaOne) Cross Tier Push Architecture (Don’t call us, we’ll push you) (S24722)4.30-5.15 PM, Hotel Nikko, Monterey I/II

• Wednesday – Push to the Limit: Rich and Proactive User Interfaces with Oracle ADF (S08620)5-6 PM, Mariott Marquis, Golden Gate A

• Thursday – Instant Agility in Oracle Fusion Middleware through Design Time @ Run Time (S08623)4-5 PM, Moscone West – 2020