Frames
An application is a collection of related units called frames. Each frame generally corresponds to one computer window of information.
The application user sees the application as a sequence of frames. It is through the frame that he or she communicates with Ingres and manipulates the data in the database. (Frames are described in more detail in
Overview of Tools and Languages.
Frames consist of forms and menus.
Forms
The form is the interface between the user and the database. It can be used just as you would use a form on a piece of paper, such as an order blank.
When you specify the type of frame you are creating, Vision creates a default form for that frame type. (See
Frame Types. You can use that form as is or modify it.
Menus
Each operation available for a frame appears as a menu item on the frame's menu. These menu items let you view records and perform basic Ingres operations.
Vision generates these menu items in two ways:
• Vision automatically creates menu items that let users manipulate data and perform basic Ingres operations, such as saving changed records or returning to the top frame of an application. (The particular menu items that Vision generates depend on how you specify the visual query. For more information about Vision-generated menu items, see
Vision Applications from a User Perspective.
• When you create a new frame, you specify a menu item to call the new frame from an existing frame. For example the ChangeOrders menu item illustrated on the Browse frame later in this chapter was specified to call a frame where orders can be modified.
Frame Trees
The frames of a Vision application are arranged in groups called trees, because they resemble family trees. Within a tree, you refer to frames by their "family" relationship to each other.
A tree consists of:
• The parent frame; this is the highest-level frame from which you view a specific tree or tree segment
• The child frames; these are the frames that the parent frame calls
Frames that have the same parent are called peer frames; peer frames also are said to be at the same level of the application.
• Any children of the child frames, and so on down the tree
This "family tree" terminology is a convenient way to refer to the frames in an application. The procedures and discussions in this guide often use these terms. But remember that the terms parent and child refer to a relationship between frames, not to an absolute position in the application. As in a human family, a parent in one context can be a child in another.