Hi,
This is a WHERE clause I have to dynamically create everytime I do a query
to my geographic database. It's fairly obvious: every object in the database
is checked against a bounding box, which is a Rectangle with x=minx, y=miny,
width=maxx, height=maxy:
public static final String createRegionWhereClause ( Rectangle r )
{
return
"(maxX BETWEEN " + r.x + " AND " + r.width + " AND maxY BETWEEN " +
r.y + " AND " + r.height + " OR " +
"minX BETWEEN " + r.x + " AND " + r.width + " AND maxY BETWEEN " +
r.y + " AND " + r.height + " OR " +
"maxX BETWEEN " + r.x + " AND " + r.width + " AND minY BETWEEN " +
r.y + " AND " + r.height + " OR " +
"minX BETWEEN " + r.x + " AND " + r.width + " AND minY BETWEEN " +
r.y + " AND " + r.height + " OR " +
"minX BETWEEN " + r.x + " AND " + r.width + " AND maxY > " +
r.height + " AND minY < " + r.y + " OR " +
"maxx BETWEEN " + r.x + " AND " + r.width + " AND maxY > " +
r.height + " AND minY < " + r.y + " OR " +
"minY BETWEEN " + r.y + " AND " + r.height + " AND minX < " + r.x +
" AND maxX > " + r.width + " OR " +
"maxY BETWEEN " + r.y + " AND " + r.height + " AND minX < " + r.x +
" AND maxX > " + r.width + " OR " +
"minX < " + r.x + " AND maxX > " + r.width + " AND minY < " + r.y +
" AND maxY > " + r.height + " )";
}
Whilst I already get very good results doing things this way, this is now
optimization time, and I was wondering if there was speedier way to execute
a such query, maybe using a user function written in C.
What do you think ?
Candide Kemmler
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