Where did the changes to the file definition go?

We may find when amending a file definition that the amendment appears to disappear or has been ignored.
Let’s take the following example is typical of this problem:
• A file named FILEB is to be defined. It is to contain a validation rule that references FILEA. However, this particular validation rule requires a special logical view of FILEA which currently does not exist.
• To set up the special logical view of FILEA which is required the definition of FILEA is amended. The new logical view, which is called FILEAV01, is successfully added to the definition of FILEA.
• The definition of new FILEB is now started. When attempting to add the validation rule that references FILEAV01 the system insists that no file with this name exists. Even using the option to choose the file from a list fails to show FILEAV01 in the list.
What has happened to the amendment made to FILEA that defined a new logical file called FILEAV01?
The answer is that although the definition of FILEA was amended the definition was not made operational.
Although logical file FILEAV01 exists in the definition of FILEA it does not exist as an "accessible" file until the amended definition of FILEA has been made operational. This is an option on the file control menu.