General Transitive Closures and Aggregate Functions
نویسنده
چکیده
General transitive closures are a convenient operation for process ing recursive structures with relational languages because they are easy to understand e ciently to implement and expressive enough to support a broad range of practical applications To further extend the expressiveness of general transitive closures we study the use of aggregate functions together with general transitive closures While general transitive closures are restricted to express linear recursion general transitive closures with aggregate functions can be used to ex press some nonlinear recursions too We will give some conditions for general transitive closures with aggregate functions to be well formed and bottom up evalueable We show how these constructs can be in tegrated in an extended SQL
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تاریخ انتشار 1991