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The COALESCE operation extracts and coalesces the value of a property that is distributed over a number of individual paths. SyntaxThe general form of a COALESCE is given below.COALESCE(property, variable)The COALESCE operation extracts and coalesces the value of the property for the set of paths that connect two nodes in the (collapsed) paths represented by the variable. The paths are implicitly collapsed prior to evaluating the COALESCE if the user forgets to explicitly collapse the path. Extracting the TRANSACTION TIMELet's start with a simple example to extract the transaction time all the 'movie' edges to a star name.
Coalescing the TRANSACTION TIMECoalescing computes the transaction time over all possible paths. Let's do the same query as above, except this time we will coalesce the transaction time rather than just extracting it.
Coalescing other propertiesAny property can be coalesced.
Curtis E. Dyreson, Michael H. Böhlen, and Christian S. Jensen © 1998-2000. All rights reserved. |
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E-mail questions or comments to Curtis.Dyreson at usu.edu |