Temporal Connectives versus Explicit Timestamps to Query Temporal Databases
نویسندگان
چکیده
منابع مشابه
Temporal Connectives Versus Explicit Timestamps to Query Temporal Databases
Temporal databases can be queried either by query languages work ing directly on a timestamp representation or by languages using an implicit access to time via temporal connectives We study the dif ferences in expressive power between these two approaches First we consider temporal and rst order logic We show that future tem poral logic is strictly less powerful than past future temporal logic...
متن کاملTemporal Connectives versus Explicit Timestamps in Temporal Query Languages Temporal Connectives versus Explicit Timestamps in Temporal Query Languages
Some temporal query languages work directly on a timestamp representation of the temporal database, while others provide a more implicit access to the ow of time by means of temporal connectives. We study the diier-ences in expressive power between these two approaches. We rst consider rst-order logic (i.e., the relational calculus). We show that rst-order future temporal logic is strictly less...
متن کاملTemporal Connectives versus Explicit Timestamps in Temporal Query Languages
Some temporal query languages work directly on a timestamp representation of the temporal database, while others provide a more implicit access to the ow of time by means of temporal connectives. We study the diierences in expressive power between these two approaches. We rst consider rst-order logic (i.e., the relational calculus). We show that rst-order future temporal logic is strictly less ...
متن کاملTemporal connectives versus explicit
Some temporal query languages work directly on a timestamp repre sentation of the temporal database while others provide a more implicit access to the ow of time by means of temporal connectives We study the di erences in expressive power between these two approaches We rst consider rst order logic i e the relational calculus We show that rst order future temporal logic is strictly less powerfu...
متن کاملIncomplete Timestamps in Temporal Databases
This paper addresses problems in representing and reasoning about a type of temporal indefiniteness that derives from having incomplete timestamps for some states, where a timestamp is called incomplete if it corresponds to only the beginning, ending, or some other portion of the full extent of the state. The approach to incomplete timestamps described in this paper combines two major component...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Journal of Computer and System Sciences
سال: 1999
ISSN: 0022-0000
DOI: 10.1006/jcss.1998.1598