The concept of a 'schema' is a pattern of thought, or physical habit, that exists in a structured order. On the other hand, 'constructive processing' is the consistent mental analysis of external variables that effects the way we behave or perceive things.
The way the two are interrelated is that a schema is a thought pattern or philosophical belief system that exists before hand, and constructive processing is added constantly and may alter and effect the former due to an adaptation of our perceptions. Schemata (plural) exist in the first place as a combination of old, learned thoughts and behaviours, with adaptation to the arrival of new information (constructive processing).
For example, a person standing at the ledge of a high building will rationalise not taking a step forward using schemata (knowing that falling from heights generally results in injury or death) in addition to constructive processing, i.e. Evaluation of the situation in front of them (standing on a high building and seeing quite clearly that if one fell, they would not survive). Combining preconceived ideas of death related to heights, along with the current, visual process of information based on where said person is standing, is how schema is related to constructive processing.
I hope this answers your question.