AbstractIn most manufacturing environments, data representing an object are scattered over multiple databases and can be updated by multiple sources. The author refers to such an environment as a multidatabase multisource (MDMS) data environment. One of the most important issues in an MDMS data environment is how to choose a value for an object when there exist multiple records of values for it. We present a model, called tuneup-schema multidatabase, by which the most beneficial set of values for a manufacturing object is determined, and the manufacturing process is optimized.