... schema and related captured by a internal database an Examples of internal database operations pipelined join, semi—join, are a processing base relation and a tree non—leaf Internal data operation ... edge to an ancestor or a node in the sibling subtree A contraction of a clique is the extrapolation of the traditional notion of an edge contraction in a graph An edge is said to be contracted ... techniques, database architecture, database machines, intelligent front ends, mass storage for very large databases, distributed database systems and techniques, database software design and implementation,...