Transaction Processing System
A transaction processing system captures the data necessary to update existing records whenever stored data about the fundamental business operations of the organization must be changed. A transaction is a unit of work that is elemental from the organization’s point of view. For example, in an order-entry system, a common transaction is entering a new order. For an accounts-receivable system, a common transaction is entering a customer payment.
The transaction processing system edits all input to ensure that it is accurate and complete. For example, a customer-order transaction is rejected if it contains an invalid account number or if the product code of the item ordered is missing. Valid transactions are accepted for further processing and invalid transactions are identified so that they can be corrected.
Management Information System
A management information system accepts valid transactions from the transaction processing system to update the contents of the database. The management information system can draw the data from the database and process it to provide management with information. It can be used to identify opportunities for improvement or to help determine alternative courses of action.
The database may contain a massive amount of details (e.g. three years of customers’ orders for a big company may require millions of records). The database is protected against loss of its original contents by creating copies of the database and/or the original transactions used to update it. Thus the database represents a vast storehouse of facts of significant value to the entire organization and is often referred to as a corporate database (e.g., the corporate-order database). A corporate database is used by many different organizations for many different purposes. Special subjects of the corporate database may be combined with other data to meet specific user needs. This collection of special-purpose data is often called an application database (i.e., a database created for a small set of users for a specific use).
Decision Support System
People use decision support systems (DSS) to access the application databases to get the key facts needed to help make decisions. The decision support system may be fairly simple and straightforward, merely producing some type of printed report containing information useful to managers. On the other hand, the decision support system may be a complex system that models some business situation and allows managers to simulate what will happen under different conditions.
DSSs contain a set of related programs and data to help with analysis and decision-making in an organization. At a minimum, DSS includes a database relating to the types of decisions being made, the capability to state problems and questions, and modelling software that can test alternative solutions. More powerful modelling software such as Integrated Financial Planning System (IFPS) and graphics software are often included. Although different levels of management benefit from decision support systems, they are used by tactical management for creating models to assist in analysis and decision-making.
A DSS can present several solutions for one problem. It permits the user to enter, retrieve, and analyse data in an ad hoc manner. The user does not have to rely on the systems department to change the program, create new relationships among existing data, enter new data, or analyse the data in a new way. As a result, information is available almost immediately. A DSS does not make decisions for users, but it does support them in their decisions. A manager then uses his/her judgment, intuition, and experience to reach a decision.
There are numerous DSS applications in business organizations. Some of the most important and widely used applications are in financial planning, manufacturing, mergers and acquisitions, new product development, plant expansions, and sales forecasting. In financial planning, banks use DSSs for budgeting and analysing the impact of changes in money market rates, financial regulations, and interest rates. Manufacturing firms use DSSs to study the impact that different combinations of production processes, and machine capacities have on production costs.
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