Ill Give it a shot.
MagID: Is the field that determins what spell it is.
MagName: Is the field given to the spell name.
EffectType: i am unsure atm, but what effects the spell?
Spell: Is the field that effects how much mp spells cost.
Power: I think its the minimum damage of the spell (Before MC/SC Effects)
MaxPower: I think its the Maximum Damage of the spell (Before MC/SC Effects)
DefSpell: The mp cost for Martial Arts (Warrior Spells)
DefPower: Prft no idea, effects mostly wiz spells.
DefMaxPower: Again no idea

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Job: What class needed, 0 = War, 1 = Wiz, 2 = Tao.
L1Need: What level for Level 1 of the spell.
L1Train: Whats needed to reach level 1
L2Need: What level for Level 2of the spell.
L2Train: Whats needed to reach level 2
L3Need: What level for Level 3 of the spell.
L3Train: Whats needed to reach level 3
Delay: Time it takes to cast another Spell after using.
Descr: i can only Assume Description. but its usless.