The Semantics of the Geographical Database Query Languages
نویسنده
چکیده
In this paper, we analyze the various philosophies to define a query language for geographical database. The differences among the three possibilities of extending the SQL language rely on the definition of the clause Select: (1) the clause Select does not accept a spatial operator and the Where clause accepts one (or several) predicate defined between attributes; (2) the clause Select accepts one (or several) spatial operator(s) with attributes as arguments; (3) the clause Select accepts one (or several) spatial operator(s) with attributes or other spatial operators as arguments. To guarantee a coherent result of a query, we present the requirements of these three philosophies.
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متن کاملThe Semantics of the Geographical Database Query Languages
In this paper, we analyze the various philosophies to define a query language for geographical database. The differences among the three possibilities of extending the SQL language rely on the definition of the clause Select: (1) the clause Select does not accept a spatial operator and the Where clause accepts one (or several) predicate defined between attributes; (2) the clause Select accepts ...
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