Definition
A punctuation is an item embedded in a data stream that specifies a subset of the domain of that stream. A data item that belongs to the subset specified by a punctuation is said to match that punctuation. A data stream is said to be grammatical if, for each punctuation, no data items will follow that match that punctuation. Consider a stream of bids for online auctions. When an auction closes, a punctuation p is embedded in the stream that matches all bids for that auction. In a grammatical stream, p indicates no more bids will arrive from that stream for that auction.
In the most common format, a punctuation is a tuple of patterns, where each pattern corresponds to an attribute of the data items in a stream. Typically, four patterns are used: a wildcard (denoted by ‘*’) is matched by all values, a literal is matched by only the given value, a list (denoted by { }) is matched by any value in the given list, and a range(denoted by [ ]) is matched by any value that falls in...
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Recommended Reading
Li J, Maier D, Tufte K, Papadimos V, Tucker PA. Semantics and evaluation techniques for window aggregates in data streams. In: Proceedings of the ACM SIGMOD International Conference on Management of Data; 2005. p. 311–22.
Tucker PA, Maier D, Sheard T, Fegaras L. Exploiting punctuation semantics in continuous data streams. IEEE Trans Knowl Data Eng. 2003;15(3):555–68.
Tucker PA, Maier D, Sheard T, Stephens P. Using punctuation sschemes to characterize strategies for querying over data streams. IEEE Trans Knowl Data Eng. 2007;19(9):1227–40.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Section Editor information
Rights and permissions
Copyright information
© 2018 Springer Science+Business Media, LLC, part of Springer Nature
About this entry
Cite this entry
Maier, D., Tucker, P.A. (2018). Punctuations. In: Liu, L., Özsu, M.T. (eds) Encyclopedia of Database Systems. Springer, New York, NY. https://doi.org/10.1007/978-1-4614-8265-9_285
Download citation
DOI: https://doi.org/10.1007/978-1-4614-8265-9_285
Published:
Publisher Name: Springer, New York, NY
Print ISBN: 978-1-4614-8266-6
Online ISBN: 978-1-4614-8265-9
eBook Packages: Computer ScienceReference Module Computer Science and Engineering