Example (Application Orientated)

We assume that your application manages addresses and there you got two tables.
The 1^st table contains many towns (town_tbl) and your next table is filled with names (names_tbl) assigned to a town.

The table names_tbl contains the town_id, to assign one town for every name.

You created your form with the eva/3 Application Builder as described at Table selection and enabled the option CascadeDelete.

CascadeDelete

If you now delete the town London also every assigned names are deleted.
Because in this case we are talking about a 1 to n relationship, the option CascadeUpdate makes no sense.

CascadeUpdate

Let us take a look at one more example.

You added another table to handle the contacts (contact_tbl).
The tables are assigned through a field called Name_ID.
There is just one name at one contact, so where are talking about a 1 to 1 relationship.

You also created your form with the eva/3 Application Builder as described at Table selection and enabled the option CascadeDelete and CascadeDelete.
If you now insert a new name there will be automatically created a new entry at the table contact_tbl and the new entry contains the Name_ID.

Cascading Properties Update / Delete