Modifying a structure

Generally speaking you can modify all fields for a structure except the structure name. See below for other restrictions that may apply depending on how the structure relates to other components in your repository, such as files and keys.

1. Highlight the structure in the Structure Definitions list and press enter.
2. Modify data in the fields as necessary. See step 2 in Defining a new structure for detailed information on the fields.

If the structure has already been assigned to a file, you can’t modify the file type because a structure’s file type must always match the file type of all files to which it is assigned. If you attempt to modify the file type, an error message is displayed when you attempt to exit the window. You must disassociate the structure from all files before you can modify the file type. (See Disassociating a structure from a file.)

Even if the structure is not assigned to a file, other restrictions may apply. You cannot change a file type to RELATIVE if access keys already exist for the structure, because relative structures can have only one access key (the record number). If the original file type is relative and the record number key has not been deleted, the only file type to which you can change is USER DEFINED. The reverse situation is also true: if the user‑defined file type was originally relative and you haven’t deleted the record number key, the only file type to which you can change is RELATIVE.

3. If you want to modify the attributes for the current structure, select Structure Functions > Edit Attributes. You can also edit a structure’s attributes from the Structure Definitions list by highlighting that structure and pressing the “Edit Attributes” shortcut.
4. Exit the window to save your changes and return to the Structure Definitions list.