insertion of data on the same time point should be managed

[mdrio]

[mdrio]

At this moment it is possible to write multiple data for the same time point. It should be avoided, raising an exception as the value already exists and/or providing an upsert function

[ilveroluca]

Try coalescing records when reading them. This can be done in the web service, like get_latest_activity does. Or it can be moved down into the database query, but I don't think PgSQL has a function to merge JSON dictionaries that we would need.