High Quality Content by WIKIPEDIA articles! Single assignment is used to describe a programming language or representation in which one cannot bind a value to a variable if a value has already been bound to that variable. In other words, a variable is initialized with (i.e. bound to) a value at the time that it is created, and it cannot be assigned to. It prevents some types of side effects, which is claimed to reduce software bugs and simplify debugging.Note: in some cases partial values could be used in more than one assignment as far as the partial values used in these assignments are compatible. Sometimes such variables are called declarative variables or dataflow variables.