In Oracle Forms, what is the relationship between a window and a canvas view in the form user interface?

Introduction / Context:
Oracle Forms is a development tool used to build data entry and query screens for Oracle databases. In the Forms user interface model, the concepts of windows and canvases are essential. A window defines where on the screen the form can appear, while a canvas defines the surface on which visual items such as text fields, buttons, and graphics are placed. This question checks whether you understand the correct relationship between these two objects in a form module.

Given Data / Assumptions:

• We are designing or understanding an Oracle Forms based user interface.
• Windows and canvases are both objects defined in the form.
• Items such as text fields and buttons ultimately appear to the user inside windows.
• Canvases are associated with windows to control what the user sees.

Concept / Approach:
In Oracle Forms, a window represents a rectangular area on the screen where form content is displayed. It can have properties such as position, size, and whether it is modal. A canvas is a drawing surface that is attached to a window. Visual items such as fields, check boxes, and buttons are placed on canvases rather than directly on windows. When the form runs, the canvas is shown inside its associated window. Multiple canvases can be assigned to the same window, and you can show or hide canvases dynamically, but the window provides the physical frame on the screen.

Step-by-Step Solution:
Step 1: Recall that items in Oracle Forms are laid out on canvases, not directly inside windows. Step 2: Recognize that each canvas is assigned to a specific window where it will be displayed. Step 3: Understand that the window defines the position and size of the area where the canvas appears on the screen. Step 4: Review the options and select the one that clearly states that the canvas holds items and is displayed inside a window. Step 5: Eliminate options that claim no distinction between canvas and window or that talk about printing, networking, or database storage, which do not match the Forms user interface model.

Verification / Alternative check:
If you have worked with Oracle Forms Builder, you will remember that when you create a canvas you must choose which window it belongs to. When the form runs, you see the window frame on the desktop and the canvas content inside that frame. This behavior confirms that the window is the outer container on the screen and the canvas is the inner surface that holds items.

Why Other Options Are Wrong:
Option B is wrong because windows and canvases are design time and runtime user interface objects, not database storage objects. Option C is incorrect because Oracle Forms documentation clearly distinguishes between windows and canvases. Option D is misleading, since data blocks map to database tables, but they are not stored in windows or canvases. Option E is unrelated because printing and networking are not the defining differences between these objects.

Common Pitfalls:
A common mistake is to think of windows and canvases as interchangeable, which can lead to confusion when configuring the layout. Another pitfall is forgetting to assign a canvas to a window, which results in items not being visible at runtime. To avoid these issues, always remember that the window defines the screen area and the canvas is the surface within that window that holds and organizes the controls.

Final Answer:
In Oracle Forms, a canvas is a surface that holds items and is displayed inside a window, which represents a physical area on the screen used to show that canvas.