Hello, wildwind, you wrote: >> single-user, one-continuous W> Then I did not understand, what sense in support result in an actual state in process of database update. Give events record Sense about the such dobavilas/udalilas/changed: all application state is stored in this database, all logic works only with it. And for example there is a window in which any list is displayed, this window creates request and listens to changes. Thus as-only they happen, the window is updated. And more that can be made a control item the list which accepts request as parameter, and itself shows everything that is necessary. Well or for example one system creates any object, and another notes at once it, since is signed on such objects, and at once processes its creation, and again there is a warranty that on completions of an operation cycle of messages, all in a correct type. And all this logic in formalized, easily readable type.