Abstract: An entity-relation database is disclosed to include a plurality of entity fields containing arrays of data elements, the data elements being related to each other in predefined sets, with each predefined set including data elements in at least two of the entity fields. At least one linked list defines the relationship between data elements between each of the predefined sets and provides a means for retrieving all of the elements of any selected predefined set from the two entity fields. The linked list consists of two distinct portions, namely, a head portion associated with each member of one entity field and a continuation portion associated with each member of another entity field, while each entry consists of a pair of addresses thereby forming a doubly linked list.

Abstract: A system for monitoring a multiparameter manufacturing process by examining on a real-time basis a stream of data units, each data unit including a numerical characteristic indicative of a current state of one of the parameters of that manufacturing process and a tag identifying the parameter. The system employs an entity-relational database to group and evaluate all data units using statistical evaluation criteria, and to identify and generate signals relating to particular testpoints in the manufacturing process so that an indication of the significance of the statistical pattern and the manufacturing process parameter involved are given in such terms as to permit human evaluation of and, if necessary, manual or automatic intervention in the manufacturing process.