In this study, a workshop production management system supporting decision making is designed for use in small and medium-sized machine workshops. Small and medium sized companies' quality, price, and delivery time issues are in a tough competitive environment. Especially such as the orders which cannot be delivered to customers in time, disruptions in production schedules and low production performance seem to be the major problems facing in this type of sector. Through this research it is aimed to design software to keep all the needed information in a suitable database and give the customers fast and accurate information. In order to support future implementation of decision support system, the software is designed such that it will enable the user to easily analyze its production parameters such as efficiency, cost deviation of production from planned cost, cost estimation of new production, etc. Due to the natural structure of this project Object Oriented database is chosen for implementation. These databases can be constructed through object-oriented language and in the scope of this work. NET based db4o is used. For software development, Unified Modelling Language (UML) is used since by using UML the database system is well defined, visualized, generated and specified considering complete project. The user interfaces are designed by using ASP. NET for easy access of the user location independently. It is seen that without using so much coding load, an effective object-oriented database can be designed. It is possible to use the same language for both application and object-oriented databases in contrast to relational databases. The designed database can be used in different machine workshops with small modifications depending on the specifications of workshops.