1. A method for managing an instance of a model, wherein the instance includes a set of nodes with associated node variables and a set of connection constraints, the method comprising the computer-implemented steps of: receiving an intent to modify the instance, wherein the intent to modify specifies a first node of the set of nodes; loading into volatile memory information associated with said first node; determining, based at least on said information associated with said first node, a first subset of said set of connection constraints, wherein said first subset of connection constraints includes all connection constraints that restrict said intent to modify, and wherein said first subset of connection constraints includes fewer constraints than said set of connection constraints; determining, based on said first subset of connection constraints, a first subset of node variables that are associated with nodes of said set of nodes, wherein said first subset of node variables includes all variables that may have associated values that affect whether any constraint of said first subset of connection constraints is violated; and loading into volatile memory a first subset of node variable information, wherein said first subset of node variable information includes only information about said first subset of node variables.