How are datetimes represented by Chronus?
A datetime is an isolated point in time known to have a given granularity. Chronus used the standard JDBC datatime format of YYYY-DD-MM HH:MM:ss:ms. All datetime literals must be enclosed in single quotes. A datetime does not have to be specified to the finest granularity – partial specifications are allowed. So, for example, only a year and month may be specified. Chronus will round partial specifications the start of the each unspecified granularity. So, ‘1999-02’ will be rounded to ‘1999-02-01 00:00:00.000’. Chronus supports three special datetime values. A special value of ‘now’ is used to represent the time when a temporal command is executed. For example, if a command wishes to restrict itself to tuples that are currently valid, it can use the ‘now’ value to represent the current time of the query. A related distinguished value is ‘+’, which can be used to represent the end time of tuples that are valid until otherwise specified. Such ongoing tuples are common in databases and th
