"Software Comparison: Visible Analyst and Microsoft Visio"
Software Comparison: Visible Analyst and MS Visio Nobuko Miyairi Spring 2002 LIS 647 Systems Approach to Library Operations Dr. Luz Quiroga Library and Information Science Program University of Hawai'i at Manoa Nobuko Miyairi 1 I. Introduction In this paper, I compared Visible Analyst (VA hereafter) and Microsoft Visio (VISIO hereafter) for the purpose of building Data Flow Diagram. As shown below, the logical sequence to build DFD is compared between two tools: each step contains criteria which I focused on: A. Creating New Diagram Diagram templates/stencils; style (notation) selection; streamlined process. B. Drawing Objects Object tools; drag and drop; labeling objects. C. Modifying Objects Menu system for modifications of objects. D. Saving DFD Saving options. E. Logical Information (Data Dictionary) Data dictionary and templates. F. Decomposing Diagram Decomposition of diagram and its treatment within file structure. G. Analyzing DFD Analyzing tool for DFD. H. Instinctive Features Comprehensibility of menus; contextual help. I. File structure & management Perspective view for the object structure; management for each item/objects. Nobuko Miyairi 2 II. Comparison A. Creating New Diagram In VA, you first have to create a "project," which packages all the diagrams and related data in a single directory. VA is good in prompting you to a dialog box for the next (anticipated) operation. When creating a new project, it provides a dialog box to let you name it, select the file path to designate where to store the data, and give a brief description about the project (see Figure 1). In the same dialog box, you can select which style of DFD you are going to create. After clicking “OK” button, it gives you another dialog box to select the diagram type, paper orientation, paper size, and so forth. When you select “Data Flow” type, it forces you to start from the context level diagram. Then again, VA prompts you to another dialog box so that you can Figure 1 designate the first object for a diagram. When you select “New” from the “File” menu in VISIO, it gives you a selection of templates. It is nice to view various kinds of diagrams and charts graphically. I chose “Data Flow Model Diagram” from “Software” template. Then it gave me the drawing screen with stencils in Gane-Sarson style. I first could not figure out how to switch to Yourdon/DeMarco style. I used “Find Shape” function and then found a set of Yourdon/DeMarco style stencils. While VISIO has a nice graphical presentation of templates, VA's contextually streamlined features are very useful in guiding the user to the next operation. If you know what/how to create, you may not have trouble with using both; but if you are a novice, then VA is quicker to start drawing a diagram. B. Drawing Objects In VA, you can select the shape of symbols you are going to draw by selecting tool icons. When you place a symbol in the drawing area, it automatically prompts you to label the object in a pop-up window (see Figure 2). VA provides this pop-up window every time you place a new symbol, and it is a nice feature that saves user's time. When you place an arrow as a data flow object, the system automatically Figure 2 hyphenates the label you enter according to Yourdon/DeMarco conventions. Nobuko Miyairi 3 While selecting one type of object, clicking the mouse button repeats placing the same symbol in the drawing area. This can be cumbersome, because you need to intentionally select the “Selector” icon if you only want to select the object. VISIO provides different levels of descriptions for the stencil. When you choose “Icons and Details”, it displays the shapes of icons with names, and a brief description for each (see Figure 3). This can be useful when you are unfamiliar with notations. Although VISIO does not prompt you to label each object, you can easily change the text label just by selecting an object and typing in. Unlike VA, placing a new object can be done by drag-and-drop from stencils. The mouse pointer stays as the “Selector,” and you can simply click on an object if you want to move it within the drawing pane. Figure 3 C. Modifying Objects By right-click on your mouse button over an object, you can pull down a menu to change its settings both in VA and in VISIO. Basically, the physical modification to an object can be done using this pull-down menu. In VA, the labeling (wording) of this pull-down menu is a bit confusing. For example, if you want to change the size of the object, you are supposed to choose "Stylize." It is much nicer to have it labeled as "Size." "Stylize" does not only resize the object but also controls its style ("Boldness", for example); but I believe it could have more intuitive label. Figure 4 In VISIO, labeling is fairly understandable: Cut, Copy, Paste, View, Format, Shape, and so on (see Figure 5). This labeling system is much more intuitive than VA. Of course, it is because they are similar to other Microsoft products and other popular PC applications, which I am accustomed to. Figure 5 D. Saving DFD In VA, you are required to save a diagram first before you perform certain functions. For example, you first need to save a new diagram if you want to "define an object" (see E Logical Information: Data Dictionary). To save DFD, you can select "Save" from "File" menu, then a pop-up window will be provided to enter the name of the diagram. Besides, if the task you performed requires saving a diagram, the system automatically prompts you to a pop-up window for saving the diagram first. Nobuko Miyairi 4 When you save a file in VISIO, you have several options in terms of file format. You can save it as drawing, stencil, template, web page, JPEG and other graphic formats, and so forth. This cannot be simply compared with VA since the demo version I used was limited in certain functionalities. However, I believe VISIO has enough options for you to save diagrams in different formats. E. Logical Information: Data Dictionary VA provides a way to save logical information about each object in DFD. When you double-click an object (or select "Define" from the pull-down menu), it opens up a window to enter all the information that can serve as data dictionary (see Figure 6). Depending on the type of object you selected, the system provides different templates. Unlike VA, VISIO does not have a logical structure behind objects. They are just graphics, and do not consist of any information over physical representation. Figure 6 F. Decomposing Diagram By selecting "Explode" from the pull-down menu, you can decompose a process in VA. The decomposed diagram automatically succeeds input/output data flow from the parent diagram. To switch between multiple levels of DFD, you select a desired window from the "Window" menu. VISIO has “sort of” decomposing function. You can have “Detail Page” for each process in a diagram, and lower level processes will be stored in the same file. They are treated as Excel worksheet-like tabs on the bottom of the drawing screen (see Figure 7 Figure 7). Although it looks similar with VA in representation, they are not hierarchically recognized by the system. G. Analyzing DFD VA has a functionality to analyze whether your DFD is logically correct ("Diagram" menu > "Analyze"). This is extremely useful for novice users, or even for experts when creating a huge set of DFD, which can be very complex. If there are errors, VA gives you a list of error messages in the form of pop-up window (see Figure 8). You can save, print the list, or you can consult Help file Figure 8 Nobuko Miyairi 5 directly from this window (see Figure 9). This context help function is helpful when you do not comprehend what is wrong with your DFD even provided with an error message. VISIO does not provide any analysis tool for DFD. It has some useful functions for database modeling (reverse engineered model, database properties, indexing, etc.) but not for DFD. Figure 9 H. Instinctive Features Overall, VA has a well-organized menu structure. Nevertheless, some functions lack intuitiveness and it was difficult for me to figure out how to perform certain tasks. For example, it took me sometime to figure out how to delete an existing DFD or project. First, I expected to see a "Delete" button in the project selection window, but there was no such thing. Finally, I found the function "Delete Project" under "Tools" menu (see Figure 10). This is not intuitive at all and I wonder why this function was put under there. Although graphical representations (icons) seem to be following conventions for popular PC applications, text labels for certain functions are sometimes confusing. For example, the pull- down menu for an object has "Explode" and "Decompose". I consulted the Glossary in Help menu, expecting to find a definition for each word, but it only had "Decompose"; "Explode" was explained in the process of "Nested Decomposition", but not found as an entry in the Glossary. Figure 10 VISIO’s interface and labeling system is more intuitive than VA. As already mentioned, it is because the menus and toolbars are following other Microsoft’s products, which I always use. I. File Structure & Management VA graphically provides a hierarchical structure of objects you have in your DFD (see Figure 11). This pane with a perspective view is called "Object Browser," and you can turn it on/off from the menu ("Options" > "Object Browser"). The Object Browser serves as a repository of objects, and you can drag and drop a certain item (Source/Sink, File, or Data Flow) to add to the current diagram. By double-clicking an object, you can call the "Define Item" window (i.e. data dictionary templates). In short, VA treats objects as a graphical representation of logical entity; whereas VISIO treats them just as a graphic, consequently does not provide contextual performance as VA does. Figure 11 Nobuko Miyairi 6 This is the biggest difference between these two tools. VISIO provides “Model Explorer” window (see Figure 12) so that you can get a hierarchical view for processes, data stores (file), and interfaces (source/sink). But it does not show any data flow. Unlike VA, you cannot drag and drop an object from this pane to add to the drawing area. It serves only as a list of objects that you have in the diagrams. Figure 12 III. Conclusion VISIO has nice features and its functionality is well beyond usual graphical applications. The interface, menu and navigation are highly intuitive as well as providing good help file. As for building DFD, however, it is not satisfactory enough to support a logical structure of the entire system. In case you are going to "draw" DFD as a graphic, VISIO is still a good choice providing flexible task performance. VA has sophisticated, contextual features that streamline the process of building DFD. It encapsulates multiple layers of DFD in one directory, and is capable of dealing with all the related data and information in depth. If you are accustomed to VA's functionalities and terminology (plus data modeling methods, of course), it will be a powerful tool that accelerates your work.