Scales relate to chords in the way that chords are created from scales.

So when a scale can be broken out into many scales...the scales can EACH relate to many chord...all the chords built within the scale.

You can learn patterns for the rest of your life, and you can still ask "how do I use these" 20 years from now.

If you want to learn a life long lesson in modes...learn the chords that belong with them.

The scale/mode are nothing more than harmony against a chords Root.

If you already have a good understanding of Intervals and Chord Construction , you can get an very indepth look at all these relationships by learn Keys, or Diatonic Theory with this document...

http://lessons.mikedodge.com/lessons/MusicTheory/Diatonic/DiatonicTOC.htm

Once you understand that you can use modes for exactly what they are - harmonic Intervals against a chord.

Then move to this...Determining What Key You are in

By knowing what Key you are in, along with the other information, you'll always know what scales to play against what chords and progression/songs.

These are things you'll USE for a lifetime instead of WONDER about for a lifetime.