open

To prepare something for use. In programming, opening something often entails allocating memory and other resources to it, and sometimes means getting exclusive access. Typically, things cannot be used until they have been opened; then they remain usable until they are closed. To open a cursor means to have the database engine process the query up to the point of locating the first selected row; this can entail significant processing and space in memory and on disk. To open a file is to locate the file and bring it into memory. To open a form is to find the compiled form file, bring it into memory, and prepare to display it. To open a 4GL window is to allocate memory for the image of the window, push it onto the window stack, and to display it on the screen.

See also 4GL window, close, cursor, file, query, resources, screen form.