The GMAP: a versatile tool for physical data independence

.<F3.733e+05> Physical data independence is touted as a central feature of modern database systems. It allows users to frame queries in terms of the logical structure of the data, letting a query processor automatically translate them into optimal plans that access physical storage structures. Both relational and object-oriented systems, however, force users to frame their queries in terms of a logical schema that is directly tied to physical structures. We present an approach that eliminates this dependence. All storage structures are defined in a declarative language based on relational algebra as functions of a logical schema. We present an algorithm, integrated with a conventional query optimizer, that translates queries over this logical schema into plans that access the storage structures. We also show how to compile update requests into plans that update all relevant storage structures consistently and optimally. Finally, we report on experiments with a prototype implementation ..

The GMAP: A Versatile Tool for Physical Data Independence

Physical data independence is touted as a central feature of modern database systems. Both relational and object-oriented systems, however, force users to frame their queries in terms of a logical schema that is directly tied to physical structures. Our approach eliminates this dependence. All storage structures are defined in a declarative language based on relational algebra as functions of a logical schema. We present an algorithm, integrated with a conventional query optimizer, that translates queries over this logical schema into plans that access the storage structures. We also show how to compile update requests into plans that update all relevant storage structures consistently and optimally. Finally, we report on experiments with a prototype implementation of our approach that demonstrate how it allows storage structures to be tuned to the expected or observed workload to achieve significantly better performance than is possible with conventional techniques. 1 Introduction ..

The GMAP: A versatile tool for physical data independence

Abstract. Physical data independence is touted as a central feature of modern database systems. It allows users to frame queries in terms of the logical structure of the data, letting a query processor automatically translate them into optimal plans that access physical storage structures. Both relational and object-oriented systems, however, force users to frame their queries in terms of a logical schema that is directly tied to physical structures. We present an approach that eliminates this dependence. All storage structures are defined in a declarative language based on relational algebra as functions of a logical schema. We present an algorithm, integrated with a conventional query optimizer, that translates queries over this logical schema into plans that access the storage structures. We also show how to compile update requests into plans that update all relevant storage structures consistently and optimally. Finally, we report on experiments with a prototype implementation of our approach that demonstrate how it allows storage structures to be tuned to the expected or observed workload to achieve significantly better performance than is possible with conventional techniques

Neo-Institutional Theory and Organization Studies: A Mid-Life Crisis?

We trace the development of neo-institutional theory in Organization Studies from a marginal topic to the dominant theory. We show how it has evolved from infancy, through adolescence and early adulthood to being a fully mature theory, which we think is now facing a mid-life crisis. Some of the features of this mid-life crisis include over-reach, myopia, tautology, pseudo-progress and re-inventing the wheel. To address these problems, we argue that institutional theorists should limit the range of the concept, sharpen their lens, avoid tautologies and problematize the concept. By doing this, we think institutional theorists could develop a narrower and more focused conception of institutions