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I am a new in this field and need help, how to code using SQL spatial a function that retrieve loops in a network.The input, flag: Geography and barrier: Geography and two spatial tables, first one will list the edges(edgekey, from_junction, to_junction, polyline) and the second table containing juctions(junctionkey, point).

The output will be a spatial table containing (edgekey, polykey, from_junction, to_junction, polyline), a single polygon will have the same polykey for each from_junction to_junction value.

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The input you describe does not suffice to detect actual polygons: loops in an abstract network can be transected by other parts of the network. It sounds rather like you are asking to dissect a region into polygons bounded by a given set of arcs or polylines. If that's the case, you really need to be applying a "geoprocessing" operation, rather than a database query. Perhaps that will set you on the right track to getting a solution. –  whuber Aug 8 '12 at 18:02
    
The function should return a set of polyline features with edgeKey not a polygons –  Amo Aug 8 '12 at 18:30
    
this part of Utility Network AnalysisTrace upstream elements • Trace downstream elements • Upstream accumulation cost • Find a path upstream • Find common ancestors of a set of locations on the network • Find connected elements • Find disconnected elements • Find multiple-path loops • Find all paths between locations –  Amo Aug 8 '12 at 18:47

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