Free E-Books

We all know and understand code reuse: Write the code once, and use it many different places.
Data abstraction is a bit more complex, but it??™s based on the notion that each layer of an application
(data management, business logic, and user interface) should do what it does best, and not
have to worry about other parts of the application. The data layer should concern itself with getting
data into and out of the data source. The business logic should concern itself with the rules
that drive the application, and the user interface presents data from the user and manages the
application??™s interaction with the user.
Bundling all of those operations behind or within a form violates the notion of data abstraction.
Every form in a bound application knows everything about the data managed by the form. Although
this works well in small applications where complete control over the data are relatively unimportant,
larger, more ambitious applications generally require significant control over the data.


Pages:
1969 1970 1971 1972 1973 1974 1975 1976 1977 1978 1979 1980 1981 1982 1983 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993