next requests are made during operation the rfm component layer 206 initializes the currency structure to indicate which index entry the currency processing has started with if the rfm component layer 206 is performing a search next operation it finds the currency structure in the rfm schema structure the rfm schema structure stores information about all of the aspects of the database tables to be accessed that must remain unchanged for the execution of the execution plan strategy as well as table and file identification i e names of the tables and files that can change without making the plan strategy inoperable in the case of the search next operation rfm component 206 checks the currency structure 39 s status to determine whether the currency has been invalidated by an update insert or delete operation and if it has then it returns an error to the requestor when valid the rfm component 206 uses the currency structure to determine the index key value to return it uses this information to identify the page ci to make a request to the io component layer 208 when all the index keys on the fine level ci have been processed by the rfm component 206 it processes the b tree index to determine what ci holds the next fine level key page if the index entry specifies that it is one of many duplicate keys then the duplicate key processing functions of the rfm component layer 206 are invoked after the index entry has been chosen the rfm component 206 updates the currency structure to indicate that the next entry was taken finally the rfm component 206 copies the index entry into the user 39 s buffer.