Note that apart from the -superscripts, which are added to relational algebra operators, the translation between SQL queries and relational algebra...

Note that apart from the -superscripts, which are added to relational algebra operators, the translation between SQL queries and relational algebra expressions has not changed at all. T u The de nitions above satisfy sequenced semantics if the temporal relational operators are sequenced with respect to their conventional relational counterparts. The next step is to de ne a temporal relational algebra with this property. DBL:?