Whats the difference between 'options' and 'overrides' in Rblpapi?

Question

In the documentation here, Bloomberg does not make a distinction in the request. The requests can only have 3 things:securities, fields and overrides.

So what are options? How do they get used? Is this a distinction imposed by Rblpapi? Can someone explain the distinction?

Please let me know if I am incorrectly understanding something.

Answer 1

option.names = "optName", option.values = "optVal"

in R, maps to:

request.set("optName", optVal); 

in Java. E.g:

option.names="periodicitySelection", option.values="MONTHLY")  
request.set("periodicitySelection", "MONTHLY"); 

Answer 2

Options are parameters that change how a Request or Subscription should behave. For example, a ref data request with returnEID=true will return the EID(s) of each security in response messages. A Subscription with interval=5.0 will make it an Intervalized Subscription.

Overrides, on the other hand, are field/value pairs that you specify in Requests to alter the form or content of the returned fields, for example, GICS_SECTOR_NAME will normally return sector name in English (or precisely the default terminal language), you can specify SECURITY_NAME_LANG=9 override to get the name in Korean. You can also "request" SECURITY_NAME_LANG field to know the language used in GICS_SECTOR_NAME field. Overrides can be used in Request/Response only (not subscriptions), and are applied to the entire request, on all fields that react to that override.