There is/was (though Trump has largely de-fanged it) - tracks officers fired or who resigned in lieu of termination.
> but police unions and the politicians they back would never let it happen.
Correct again. The Unions that represent ~70% of police across the country have managed to get into their CBAs that the database is not to be used for hiring or promotion decisions (i.e. not to be used).
> The department said it has changed its policy to restrict Flock data and all other law enforcement sensitive systems from being accessed on officers’ personal devices.
So next time, they can wait 'til they get to work to stalk people?