Udo W. Lipeck

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The goal of this article is to present an algorithm to simplify the automatic generation of descriptions of XML document structures. In particular we show how to obtain a DTD (document type definition) for data whose structure is described by a conceptual data model. An important objective of this translation is to preserve as much structural information(More)
The integration of heterogeneous geospatial data offers possibilities to manually and automatically derive new information, which are not available when using only a single data source. Furthermore, it allows for a consistent representation and the propagation of updates from one data set to the other. However, different acquisition methods, data schemata(More)
ing from the latter examples, we can give a general rule for trigger optimizations: Remember that we assume that the loop label β at node vi has been valid for all object combinations at situation vi. Thus any subcondition β ′ of β specialized to such object combinations and appearing in the disjunction of outgoing edge labels (β ∨ β1 ∨ . . . ∨ βd) can be(More)
Our goal is to generalize the well known bottom-up, set-oriented query evaluation for deductive databases in two aspects: First, we consider arbitrary clauses as rules in the database, not only Horn clauses or clauses with stratified negation. This allows to represent disjunctive information, in the database as well as in answers to queries. We utilize NF2(More)
This paper presents a methodology for the stepwise specification of dynamic database behaviour. A conceptual schema is described in three levels: data, objects and transactions. To determine which sequences of database states are “admissible”, integrity constraints on objects are given in temporal logic. Transactions are specified by(More)