I don’t know if it was just me, but for a while I was very confused about the relationship between BPMN (Business Process Modeling Notation) and BPEL (Business Process Execution Language).
So I decided to so a quick search on the subject and to write out what I found here.
- BPMN is a way for business analysts to describe business processes using a standardized graphical representation
- BPEL is an executable language for specifying interactions with Web Services (exclusively) and is executed by a BPEL execution engine
So BPMN is geared towards business users, the graphical notation is more familiar to them. BPEL is used by developers and is not considered business user friendly.
BPMN diagrams can actually be converted to BPEL although there are some limitations as to what BPEL can actually implement, so it is possible to create diagrams in BPMN that can’t be converted to BPEL[1].
As I was reading more on the subject I found that XPDL (XML Process Definition Language) might actually be part of the answer to that problem.
And as opposed to BPEL, XPDL can actually represent everything from BPMN. So then the relationship would be to go from BPMN to XPDL to BPEL.
Sandy Kemsley has an interesting post on the subject of XMPL and BPEL, and according to her, the only reason to go to BPEL would be if your BPM Engine actually used that format. But XPDL would allow you to take your BPMN diagram and convert it to the format used by your specific BPM Engine (no need to use BPEL).
So is BPEL obsolete? It might be heading that way unless your BPM Engine uses it specifically for execution. As long as vendors have support for XPDL it should be possible to export and import processes from one product to another.
Here are some of the interesting articles I found that might be useful if you are interested in the subject.
XPDL and BPEL by Sandy Kemsley
BPMN-BPEL in Perspective by Bruce Silver
Why BPEL is not the holy grail for BPM by Pierre Vigneras
Why all this matters by Ismael Ghalimi
WfMC counters XPDL criticism, argues three standards count
[1] BPMN FAQ at http://www.bpmn.org/Documents/FAQ.htm
Tags: BPM