You can use local and server db in the same application (and indeed in the same process flow, as explained in http://www.tersus.com/#Id=3219, and I quote: "To use a client-side database in a Tersus application, set the clientSideDatabase property of the root system to "local". This affects all database actions not wrapped with a service (database actions inside services will continue to behave as usual)."
Note that there is no support for cross-tier (i.e. accessing both client and server db) transactionality (in the strict database-sense of the word) - You can possibly model certain aspects of transaction-like behavior yourself, where failure of a later action rollbacks previous changes, but this should not be considered a reliable mechanism.
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