In the context of a constraint-based or rule-based model, in which nodes are interrelated by constraints, rules, and conditions, addition of and changes to nodes need to be validated against relevant constraints. A mechanism is provided for performing such validation without loading the entire configuration, which includes a set of constraints and a set of node variables. In response to an intent to modify a node, a subset of the set of constraints is determined, which includes all constraints that restrict the intent to modify. Further, a subset of the set of node variables is determined, which includes all node variables that may have values that affect whether any of the subset of constraints is violated. A subset of node variable information is loaded into volatile memory, which includes only information about the subset of node variables, rather than information about all of the nodes of the model.