Media failure occurs when someone accidentally deletes a database file from the file system.
Sometimes you want the deletes to cascade; other times you don't.
This deletes the invitation, since we don't need it any more.
The form knows to look for that temporary file, reads it, populates it as necessary, and deletes the file.
At the end of the semester, you might run a script that deletes and cleans up all the class WPARs.
Listing 14 retrieves the current Psycho document, deletes it in CouchDB, and then recreates it by adding a new movie-title key with the current ID value and removing the ID from the map.
When an object is created, altered, or dropped, the database manager inserts, updates, or deletes rows in the catalog tables that describe the object and its relationships to other objects.
Whoever violates state regulations and deletes, alters, or adds the data or application programs installed in or processed and transmitted by the computer systems, and causes grave consequences, is to be punished according to the preceding paragraph
In reality, it's up to you to decide whether you want your classes to maintain strict referential integrity (in other words, have all deletes cascade) or to allow a looser relationship.
