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.