This document summarizes the proposals before the SQL3 committees to allow the addition of tables with valid-time and transactiontime support into SQL/Temporal, and explains how to use these facilities to migrate smoothly from a conventional relational system to one encompassing temporal support. Initially, important requirements to a tdiscussed. The proposal then describes the language additions necessary emporal system that may facilitate such a transition are motivated and to add valid-time support to SQL3 while fulfilling these requirements. The constructs of the language are divided into four levels, with each level adding increased temporal functionality to its predecessor. A prototype system implementing these constructs on top of a conventional DBMS is publicly available.