Update Semantics of Relational Views

Bancilhon, F.; Spyratos, N.,
Bancilhon, F
Spyratos, N
TODS, 1981
Citations range: 
100 - 499

A database view is a portion of the data structured in a way suitable to a specific
on views must be translated into updates on the underlying database. This
translation process in the relational model.
The procedure is as follows: first, a “complete” set of updates is defined such
(i) together with every update the set contains a “return” update, that is, one
back to the original state;
(ii) given two updates in the set, their composition is also in the set.
To translate a complete set, we define a mapping called a “translator,” that
view update a unique database update called a “translation.” The constraint
take the database to a state mapping onto the updated view. The constraint on
a morphism.
We propose a method for defining translators. Together with the user-defined
“complementary” view such that the database could be computed from the view
We show that a view can have many different complements and that the choice
determines an update policy. Thus, we fix a view complement and we define the
view update in such a way that the complement remains invariant (“translation
complemen$‘). The main result of the paper states that, given a complete set
has a translator if and only if U is translatable under constant complement.