IBMDB2I table is created, a File Level
ID (FID) file is created in the database directory. This file has
an extension .FID and contains the last known FID of the
associated DB2 for i physical file. The
engine uses this FID value to determine whether incompatible
changes have been made to the table by an external (non-MySQL)
interface. If the physical file is altered, DB2 for i
automatically generates a new FID. The next time
IBMDB2I attempts to access the file, it will
detect that the new FID does not match the known FID, and it will
prevent MySQL from using the table.
In some cases, the changes to the physical file that cause the FID
to be updated may not adversely affect access through MySQL and
IBMDB2I. In this case, a user may wish to
override the FID check that
IBMDB2I performs. A
user with appropriate permissions may do so simply by deleting the
.FID file associated with the table and
FLUSH TABLE statement against the
IBMDB2I will then regenerate the file
with the new FID the next time the table is accessed from MySQL.
If triggers or constraints are applied to the table from a native DB2 interface, they will be respected when accessing the table from MySQL, but MySQL will have no knowledge of the triggers or constraints. Likewise, views and indexes can be created over the tables from a DB2 interface, but the indexes will not be accessible from MySQL.