Represents flags for RDB$ROUTINES system table.

    Bit
    Position   Description

    0          Routine is a function. (Call returns a result.)
    1          Routine is not valid. (Invalidated by a metadata
               change.)
    2          The function is not deterministic (that is, the routine
               is variant). A subsequent invocation of the routine
               with identical parameters may return different results.
    3          Routine can change the transaction state.
    4          Routine is in a secured shareable image.
    5          Reserved for future use.
    6          Routine is not valid. (Invalidated by a metadata change
               to the object upon which this routine depends. This
               dependency is a language semantics dependency.)
    7          Reserved for future use.
    8          External function returns NULL when called with any
               NULL parameter.
    9          Routine has been analyzed (used for trigger dependency
               tracking).
    10         Routine inserts rows.
    11         Routine modifies rows.
    12         Routine deletes rows.
    13         Routine selects rows.
    14         Routine calls other routines.
    15         Reserved for future use.
    16         Routine created with USAGE IS LOCAL clause.
    17         Reserved for future use.
    18         Reserved for future use.
    19         Routine is a SYSTEM routine.
    20         Routine generated by Oracle Rdb.
               Other bits are reserved for future use.