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Two kinds of abstraction that are fundamentally important in database design and usage are defined. Aggregation is an abstraction which turns a relationship between objects into an aggregate object. Generalization is an abstraction which turns a class of objects into a generic object. It is suggested that all objects (individual, aggregate, generic) should(More)
Aggregation is introduced as an abstraction which is important in conceptualizing the real world. Aggregation transforms a relationship between objects into a higher-level object. A new data type, called aggregate, is developed which, under certain criteria of “well-definedness,” specifies aggregation abstractions. Relational databases defined(More)
Multibase is a software system for integrating access to preexisting, heterogeneous, distributed databases. The system suppresses differences of DBMS, language, and data models among the databases and provides users with a unified global schema and a single high-level query language. Autonomy for updating is retained with the local databases. The(More)
An approach for implementing a “smart” interface to support a relational view of data is proposed. The basic idea is to employ automatic programming techniques so that the interface analyzes and efficiently refines the high level query specification supplied by the user. A relational algebra interface, called SQUIRAL, which was designed using(More)
Arabidopsis thaliana and Pseudomonas syringae pathovar tomato (Pto) provide an excellent plant-bacteria model system to study innate immunity. During pattern-triggered immunity (PTI), cognate host receptors perceive pathogen-associated molecular patterns (PAMPs) as non-self molecules. Pto harbors many PAMPs; thus for experimental ease, many studies utilize(More)
There are significant advantages to tailoring hardware storage devices to support high level data models in very large data bases. A storage device that can assume some of the data selection functions traditionally performed by the CPU can substantially reduce the amount of data to be transferred to the CPU. This reduction together with increased(More)
FLAGELLIN-SENSING2 (FLS2) is the plant cell surface receptor that perceives bacterial flagellin or flg22 peptide, initiates flg22-signaling responses, and contributes to bacterial growth restriction. Flg22 elicitation also leads to ligand-induced endocytosis and degradation of FLS2 within 1 h. Why plant cells remove this receptor precisely at the time(More)