bug #7849
Updated by Andreas Müller almost 5 years ago
Currently it often happens that DB preferences are not (correctly) saved if pressing OK or Apply in DB preferences dialog.
We need a framework that makes it easy to always handle save of preferences correctly.
The framework may include:
* a registry which returns a list of all available pref.predicates, including the expected default values (for all predicates allow override = true must be part of the default value)
* when opening TaxEditor and when opening the DB preferences view all registered values are freshly read from DB
* when opening pref view all values are written to the UI including values for allow override
* when saving cache is emptied and reloaded for registered list of predicates, all values are read from the UI (if available there), only those values NOT yet handled via UI must NOT be deleted from cache (theses might be experimental feature with no configuration UI available yet)
* when saving all predicates of the registration are saved to database
* if value+allowOverride = default value => delete
* otherwise: save value (API will decide if create or update is needed
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This ticket should also include a check for all existing UI pages if they work and throw no exceptions (especially with a DB with empty CdmPreference table), see also #7848
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Further improvements:
* ~~buttons buttons "Apply" and "OK" should be disabled if no changes are available since last save, this also holds for the local prefs dialog~~ => #8385 dialog