Temporal Intersection

From: cc <chris.colclough_at_nospam.jhuapl.edu>
Date: Mon, 26 Feb 2007 17:03:49 -0500
Message-ID: <ervlg5$s4d$1@aplcore.jhuapl.edu>

Given a set of timelines, show the periods of intersection for those timelines. I'd like to be able to apply an overlaps operator, but Oracle 10R2 does not appear to implement one. I've also peeked at using SDO, but that seems unnecessarily complex. The Java Line2D class has an intersects method, but I'd prefer to implement in SQL, if possible.

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E1, E2, E3, E4 - events
B - begin
E - end

..............................................................................................
E1

B--------------------------------------------------------------------------E

E2 B------------------------E

E3    B--------------------------------------E

E4                   B-------------------------------------------E

Given a baseline event E1, I'd like to determine the period of intersection B(4) to E(2), since that time span
contains information coincident to all events.

A more complex case follows:

...............................................................................................

E1    B----------------------E            B-------------------------E 

B---------E

E2   B----------------------------E 

B-------------E

E3         B--------------------------------------E 
B----------------------------E

E4 B--------------------E            B-----------------E 
B---------------------------E

In this case, I'd like to determine the following periods of overlap:

B(3) through E(4)and B(2) through E(1) Received on Mon Feb 26 2007 - 16:03:49 CST