Understand the differences between DCN with payload and DCN without payload.
- DCN without payload – calls MBO operations, where the name used
in the DCN request matches that of the MBO definition.
- The DCN requester sends an MBO operation execution request,
along with operation parameters, to Unwired Server.
- Unwired Server executes the operation,
(effectively calling the EIS operation), and updates the cache database
(CDB), if needed, depending on the operation's cache policy.
- Unwired Server returns a DCN status message
to the requester.
Note: Be careful when naming MBO operations in
Sybase Unwired WorkSpace, for example, an EIS-affecting operation
named "delete" may be easily confused with the direct cache-affecting operation
named :delete.
- DCN with payload – calls only the two direct cache-affecting
operations (:upsert or :delete), which always exist for an MBO, and are not related to
user-defined MBO operations.
- :upsert – the message must contain
name/value pairs for every required attribute, and the name must exactly
match the MBO attribute name.
- :delete – provide only the name/value
pairs for the primary key column(s).
These operations respectively insert or update, or delete a row in the CDB.
Calling either of these operations does not trigger any other refresh action. A
typical sequence of events might be:
- Some event initiates the DCN request (a database trigger for
example).
- The Unwired Server cache could be updated
directly from the EIS, or the DCN request could originate from a source
other than the EIS. The actual data (payload) is applied to the cache,
through either an :upsert (update or
insert) or a :delete operation.
- Unwired Server returns a DCN status
message to the requester.