The file directory is an internal administration structure of the database system. The file directory contains the following, among other things:
? The assignment of the root pages of the B* trees to the table IDs
? The assignment of the initial pages of page chains to the table IDs
? Type flags (specify whether a table contains primary data, secondary keys or LONG values)
? Statistical information on the number of data records and the size of the tables
Each internal file in the file directory has a unique file number (8 bytes long).
For more information on the file directory, see, among others, system tables FILES and FILEDIRECTORIES.
Concepts of the Database System, Logical Access Structures
Reference Manual, System Tables