  Reflecting our experiences in areas, like Algebraic Specifications, Abstract
Model Theory, Graph Transformations, and Model Driven Software Engineering
(MDSE), we present a general, category independent approach to Logics of
First-Order Constraints (LFOC). Traditional First-Order Logic, Description
Logic and the sketch framework are discussed as examples. We use the concept of
institution [Diaconescu08,GoguenBurstall92] as a guideline to describe LFOC's.
The main result states that any choice of the six parameters, we are going to
describe, gives us a corresponding "institution of constraints" at hand. The
"presentations" for an institution of constraints can be characterized as
"first-order sketches". As a corresponding variant of the "sketch-entailments"
in [Makkai97], we finally introduce "sketch rules" to equip LFOC's with the
necessary expressive power.
