Today I want to share one of the most important concept, web-based business applications communicate with each other, producer applications enqueue messages and consumer applications dequeue messages.
What is Queuing
. A producer may stipulate a delay before the message is available to be consumed, and a time after which the message expires. Likewise, a consumer may wait when trying to dequeue a message if no message is available. An agent program or application may act as both a producer and a consumer. Producers can enqueue messages in any sequence. Messages are not necessarily dequeued in the order in which they are enqueued. Messages can be enqueued without being dequeued.
Above diagram is indicate queue. Using queue you can created safer side from your data because its prevent to data loss. Enqueued messages are said to be propagated when they are reproduced on another queue, which can be in the same database or in a remote database.
What is Adavance Queuing
Advanced Queuing provides database-integrated message queuing functionality. Advanced Queuing leverages the functions of the Oracle database so that messages can be stored persistently, propagated between queues on different machines and databases, and transmitted using Oracle Net Services, HTTP(S), and SMTP.
Adavance Queuing integrated with Application
Web-base application advanced Queuing provides the message management functionality and asynchronous communication needed for application integration. In an integrated environment, messages travel between the Oracle database server and the applications and users, as shown in below screen. Using Oracle Net Services, messages are exchanged between a client and the Oracle database server or between two Oracle databases. Oracle Net Services also propagates messages from one Oracle queue to another. Or, as shown in below screen shot, you can perform Advanced Queuing operations over the Internet using transport protocols such as HTTP, HTTPS, or SMTP. In that case internet application, client or user, XML messages.
Interfaces to Advance Queuing
Advance Queuing Functionality through the following interface.
- Java using the Oracle. (AQ Java Package).
- Java Message Service JMS using Oracle (JMS Java Package).
- PL/SQL using DBMS_AQ, DBMS_AQADM and DBMS_AQELM.
- Internet access using HTTP, HTTPS and SMTP.
Features of Advanced Queuing
Advance Queuing following features.
- Structured Payloads.
- XMLType Payloads.
- Point to point and publish subscribe message.
- Internet Integration.