Oracle Built−in Packages- P50: Ah, for the good old days of Version of PL /SQL! Life was so simple then. No stored procedures or functions and certainly no packages. You had your set of built−in functions, like SUBSTR and TO_DATE. You had the IF statement and various kinds of loops. With these tools at hand, you built your batch−processing scripts for execution in SQL*Plus, and you coded your triggers in SQL*Forms , and you went home at night content with a good day's work done. | Appendix A What s on the Companion Disk NOTE Oracle AQ first became available with Oracle . A number of Oracle AQ features described in this chapter were added in Oracle . These additions will be noted but it is generally assumed in this chapter that you have installed and are using Oracle which should be widely available by the time this book is published. Oracle AQ Concepts Oracle AQ provides message queuing as an integrated part of the Oracle server. It provides this functionality by integrating the queuing system with the database itself. Oracle Corporation is therefore now beginning to describe Oracle8 not only as an object-relational database but also as a message-enabled database. Its intention is to free application developers from having to construct a messaging infrastructure or rely on a third-party tool such as a TP monitor . Instead they can use AQ and devote their efforts to implementing their own specific business rules. General Features The following list summarizes Oracle s perspective on the features of the AQ facility that it offers to developers SQL-based access and management Messages are placed in normal rows in a database table. They can be queried using standard SQL. Thus users can use SQL to access the message properties the message history and the payload. All available SQL technology such as indexes can be used to optimize the access to these messages. Integrated database-level operational support All standard database features such as recovery restart and enterprise manager are supported. Oracle AQ queues are implemented in database tables thus all the operational benefits of high availability scalability and reliability are applicable to queue data. In addition database development and management tools can be used with queues. For instance queue tables can be imported and exported. Structured payload Users can use object types to structure and manage the payload . content . RDBMSs in general have had a far
