Active database management systems can provide general solutions to data management problems in control applications. This thesis describes how traditional control algorithms and high-level operations in a control system can be combined by using an embedded active object-relational database management system as middleware. The embedded database stores information about the controlled environment and machinery. The control algorithms execute on a separate real-time server. Active rules in the database are used to interface the model of the environment, as stored in the database, and the control algorithms. To improve information access, the control system is tightly integrated with the database query processor.A control-application language specifies high-level manufacturing operations which are compiled into queries and active rules in the database. The thesis describes how the generated active rules can be organized to solve problems with rule interaction, rule cycles, and cascading rule triggering. Efficiency issues are addressed. The thesis also presents practical experience of building the integrated control system and the requirements such systems put on an embedded adbms.