Database Structure on Camunda


#1

I have read the documentation on below link. https://docs.camunda.org/manual/7.5/user-guide/process-engine/database/. but I still did not get, what are the tables that store BPMN diagram details when deploying project. Can someone explain this.
Thank You,
Rish


#2

Hi @Rish,

The table that stores BPMN diagrams is ACT_GE_BYTEARRAY. It stores also other kind of BLOBs, i.e. not every entry is a BPMN diagram.

Cheers,
Thorben


#3

Hi @thorben

I am sorry for the late reply. So when starting a process on a workflow, does it load the required parameters to ACT_RU_* tables from ACT_GE_BYTEARRAY table?

thank you,
Rish.


#4

Hi,

More detail can be found here [1]

As the docs say, the 'RE" tables are the repository tables, GE general. Thus large CLOBS or BLOBS are stored as ByteArrays in the GE table, however the core engine constructs are in the RE tables. Runtime and history are also separate tables…

regards

Rob

[1] https://docs.camunda.org/manual/7.8/user-guide/process-engine/database/#database-schema


#5

Hi,
Thank You @Webcyberrob. I referred the documentation on above link. Could you please explain the answer for my above question.
Thank You,
Rish.


#6

Hi,

OK the byte arrays are just for storage. There is also a deployment cache (see [1])

So when process instance is started, the model would typically be in the cache. The DB may be hit to ensure the latest version etc…

Do you have a particular use-case that requires in depth data schema knowledge?

regards

Rob

[1] https://docs.camunda.org/manual/7.8/user-guide/process-engine/deployment-cache/


#7

Hi,
Thank you @Webcyberrob. Your answer was really helpful and I got a clear idea.
Regards,
Rish