Darwen, Hugh2018-11-022018-11-0220142014http://196.43.179.3:8080/xmlui/handle/123456789/9671.Introduction; 2.Values, types, variables, operators; 3.Predicates and propositions; 4.Relational algebra-The foundation; 5.Building on the foundation; 6.Constraints and updatingen-USSQL: a comparative surveyBook