Data Catalog Organization with Links

Use links when you want an item in the data catalog to appear in more than one directory; you can use hard links or soft links for this purpose.

Creating a link to an item in the data catalog does not create a copy or replica of any data. It simply creates a new catalog entry that points to the same object. There is no performance penalty for accessing an object via a newly created link. The data catalog supports two kinds of links:

A hard link is an alternate name for an item in the data catalog. Changes to the object’s other names have no effect on the hard link: for example, you can move or change a file’s original name and the hard link will still know where to find the file. To delete a hard-linked object, you must remove the original name. Because they are more robust, hard links are used most often. For instructions on creating hard links, see the Data Federation Administration Guide, part of the DI Suite documentation set, which is available on the Sybase Product Manuals Web site at http://sybooks.sybase.com.
A soft link is a pointer to a particular location (name) in the data catalog. If the object at that location is moved, deleted, or renamed, the soft link leads nowhere. Soft links are used infrequently and can be created only in the CLI. For instructions on creating soft links, see the Data Federation Command Reference, part of the DI Suite documentation set, which is available on the Sybase Product Manuals Web site at http://sybooks.sybase.com.