Add ST_Holes

This looks complicated in PostGIS. Something like:
    SELECT AsText(InteriorRingN(
        GeometryN(geom, gn.n),
        NumInteriorRings(GeometryN(geom, gn.n))))
            AS geometryOfHole FROM areas,
        generate_series(1, 1000) gn(n)
            WHERE NumGeometries(geom) >= gn.n
            AND NumInteriorRings(GeometryN(geom,gn.n)) > 0

See here:
http://lists.osgeo.org/pipermail/postgis-users/2007-August/016829.html
Add ST_ToMultiSegments

This seems to be complicated in PostGIS. See
http://stackoverflow.com/questions/7595635/how-to-convert-polygon-data-into-line-segments-using-postgis