Asynchronous triggers can be implemented in different ways, and one common practice is to use a queue. A queue is used to detect changes in the tables, and then based on the base table, specific checks can be done. As we are introducing a new concept of queues here, we will keep the spatial constraint part simple and do the validation checks using an asynchronous trigger.
Oracle provides PL/SQL procedures in the
DBMS_AQ package for creating and using queues. In our example, a simple queue is used to insert information about new rows of data coming into the
LAND_PARCELS table. Then, an asynchronous process can take entries out of the queue and process them one at a time.
We first create a type ...