Hi @hissdev!
If you are using ODK-X to create the identifiers (the uuid) you would never end up with two of the same uuid, so duplication would be avoided. But if you are meaning to avoid two records for the same patient, for example, that you would have to program in. For example if there is a unique identifier, you can mandate that it is entered once and only once by counting the number of times it is already in the database using async_assign (see customizing prompts here: Using ODK-X XLSX Converter — ODK-X Docs). We do something similar in making sure people record only one father in 2_2_Father’s Characteristics section of this form quest2_00_0_ELMPS.xlsx (727.8 KB)
The zcheck_father variable is assigned based on a query counting the number of fathers an individual has entered, and it must be exactly one. You could do something similar for any kind of duplication you want to check for. The key is to set up the query with the right variables that should only occur in unique combination once.