SQL+i: Adding Temporal Indeterminancy to the Database Language SQL

This paper introduces SQL+i, a temporal relational database management system (TRDBMS) whose aim is to incorporate both determinate, indeterminate, and relative temporal facts which may be declared at multiple and even mixed levels of granularity in a uniform, natural, and unambiguous manner. We use the SQL query language as the basis for the SQL+i query language, utilising a temporal algebra whose aim is to reduce any periods of indeterminacy to a minimum level whilst still maintaining the consistency of the database. By means of a motivating example, we present our underlying model of time and the SQL+i temporal data types, along with the data definition and manipulation language extensions necessary to manipulate SQL+i relations and data. Section