How does the Oracle CEP work?

I have some questions concerning the Oracle CEP. It would开发者_如何学Python be fine if somebody could answer them.

1. What are the differences between sequences and relations?
2. How often each query is executed?
3. What are the cases when we have to convert relation to sequence?
4. How the join statement works? Is it applicable only for relations?
5. According to the documentation table and cache event source are pull event sources. Does it mean that the database table or cache will be queried for each event in the current relation when performing join statement?

Thanks in advance.

I have not looked into oracle CEP tooling, but looking at the questions I have feeling that the basics of CEP might be helpful (excuse me if I am wrong and ignore this post). I suggest (if you have not already) to first understand how CEP engines work. Instead of running queries against the data, the continuous stream of data is evaluated against the static query.

http://www.ebizq.net/topics/cep/features/9313.html