An RdbRelVar are variables that take on RdbRelations as their values.
Why is the distinction between an RdbRelVar and an RdbRelation important?
The former contains a relation, the latter is a relation. Relations are immutable and do not change. Therefore, state change in a RelationalDatabase is represented by changing the value of a relation variable, or relvar for short. The answer to the question might be better understood in terms of another question: Why is the distinction between an integer variable and an integer important? -- DaveVoorhis
Thanks for the crystal clear explanation and illustration! --BrandonCsSanders"replace, don't change" is kind of a functional viewpoint of things (FunctionalProgramming).EditHint: Merge with RelVar and RelationalVariable.