How to Plan the Application
Take time to plan an application carefully before you create it. The following guidelines can help ensure that your application is useful and effective:
• Design the flow of the application as a whole, including the hierarchy of its parts; that is, decide which frames call other frames, procedures, or other Ingres tools. (The application flow diagram in Vision lets you see the structure of your application as you build it, but you must not use it as a substitute for planning the application in advance.)
• Decide on a unique name for the application.
• Understand the users of your application and the information they need. Based on that, decide whether to restrict access to certain parts of the application. For example, your application can contain salary information that only managers are allowed to see. Define different frames as separate points of entry for different groups of users and decide where to use passwords.
• Be sure that the users of your application have the necessary privileges to use the tables that the application accesses. For example, if your application includes a frame to change records in a table, users must have update privileges for that table.
See the database administrator for your database if you need more information about user privileges.
• Consider where you can utilize:
– Global variables, where data is provided for the entire application
– Records, where a group of values is logically related
– Constants, where a set value can stand for a value, number, formula, or quoted string
• Design the individual frames and procedures in the application to give quick access to the information the users need.
• Decide which frame to use as the start frame. The start frame or procedure (sometimes called the top frame) is the point at which a user starts the application.
– You can establish more than one starting point, allowing users to enter an application at exactly the frame they need without having to move through a sequence of menus.
– In ABF, you can use the Application Defaults frame to define a default start frame or procedure.
• Know your database by knowing what the tables are and what data they contain, so that you know which tables to use with which frames. Also, be aware of any tables you must create for an application.
You can examine the structures of existing tables at various points while creating an application (see
Examining Tables on page 176. It is generally more efficient to have the tables you need before you create an application, but if necessary you can define new tables:
– In Vision, use the Tables Utility to create new tables while working in Vision.
– In ABF, you can define new tables within the database as you create an application. To enter data into newly created tables, call QBF. These procedures are described in
Building Applications on page 11.
• For large applications, decide in what order to build your application; that is, whether to work horizontally, creating all the peer frames at each level, or vertically, creating a child of the top frame and its entire tree before moving on to the next child of the top frame.
One advantage of creating an entire tree at a time is that you can test each tree after you create it.
• Decide where to use advanced features to better meet your users' needs.
These advanced features let you specify a wide range of complex queries. In general, however, you must try to keep your applications as simple as possible to make them easier to use and maintain.
Last modified date: 04/03/2024