Re: COBOL Compiler for Windows

On Fri, 2 May 2008 11:55:22 +1200, "Pete Dashwood"
<dashwood@[EMAIL PROTECTED]
>
wrote:
> Suppose, as each transaction occurred in real time it kicked of 
>a sub task (maybe running on a different procesor) that added the
necessary 
>report line to the collection right then and there... No need to filter
by 
>date or scan databases, just create the line in real time. (The report 
>object could contain a method that filtered its own collection by date as

>the lines were sent to the print spool. You can argue that this is also a

>batch process, but it isn't within the scope I defined above...)

It's called a Materialized View in Oracle. You don't have to write
anything except 

create materialized view foo 
  build immediate refresh on commit enable query rewrite
  as select customer, count(*) from customers group by customer;

Oracle remembers the select. Whenever you insert or delete from customers,
it
automagically updates foo. If someone issues the select ... from customers
.., Oracle
figures out it has the result set in foo and changes the query to read
foo. 

Data warehouses use this all the time. They scan the logs for frequent
long-running
queries and cast them into materialized views without the user's knowledge
or
participation. Suddenly the queries run much faster. 

On other databases, you can do it with triggers, but getting it to use the
view
automatically takes a bit of work.