Different constraints will be generated depending on the method of geometry creation. LINE PARALLEL, LINE PERPENDICULAR, LINE HORIZONTAL, and LINE TAN2 all convey different intentions, and all will result in different constraints.

Even if two drawings look identical, they probably will have different constraints if different construction techniques were used to create them. For example, consider these two lines. Each is connected to a fixed point at one end. But one was created with LINE TWO_PTS and the other was created with LINE PT_ANG_DIST. Both drawings look the same:

But the constraints are different: