writeToDataStoreEntity vs writeToMultipleDataStoreEntities

writeToMultipleDataStoreEntities, is looking for multiple entity data store to establish FK relationship,  this function not work if provide  single entity... that why there are 2 function provided by Appian.   

I also tried with 2 different entities, but didn't work. what is FK btw?

The a! writeToMultipleDataStoreEntities method writes multiple CDT values to multiple entities within the same data store based on your input. Make sure your parameters are correct.

Here's an example of using a!MultiDataStoreEntities to store data from local variables on the click of a button.

a!localVariables(
  local!name: a!map(name: "D", age: 18),
  a!buttonWidget(
    label: "Submit",
    saveInto: {
      a!writeToMultipleDataStoreEntities(
        valuesToStore: a!entityData(
          entity: cons!DAF2_consProm,
          data: local!name
        )
      )
    }
  )
)

Here FK refers to foreign key

Sorry, but that is not true. This has nothing to do with foreign keys.

The only difference is that a!writeToDataStoreEntity() can write one or more rows to a single entity in one data store. a!writeToMultipleDataStoreEntities() can write one or more items to one or more entities in only one data store

a!writeToMultipleDataStoreEntities(
              valuesToStore: {
                a!entityData(
                  entity: cons!AF_EXCELPIPELINE_CONS,
                  data: local!pipelinetest
                ),
                a!entityData(
                  entity: cons!AF_EXCELTASK_CONS,
                  data: local!tasktest
                )
              }
            )

this is my code. I have verified that both EXCELPIPELINE and EXCELTASK are in the same data store

Code looks fine as far as I can tell.

Maybe check both your constants and make sure they are pointing to the DSE.

Also make sure there isn't some constraint on the database that may be preventing the insert.

According to the example i mentioned above, the a!writeToMultipleDataStoreEntities() function is working properly. Ensure your constants and data are correct, or remove the parameters and retry.

what are some possible constraint on the database?

if it works for a!writetodatastoreentity, I don't have a reason to suspect it doesn't work for a!writetomultipledatastoreentities right?

If you execute this function and do not get any error message, then the data is in the table. So, If you do not see the data in the tables, there must be an error message somewhere. Did you check this? The tomcat stdout log file might be a good place.