Definition
A Web wrapper is a software application that extracts information from a semi-structured source and converts it to a structured format. While semi-structured sources, such as Web pages, contain no explicitly specified schema, they do have an implicit grammar that can be used to identify relevant information in the document. A wrapper learning system analyzes page layout to generate either grammar-based or “landmark”-based extraction rules that wrappers use to extract data. As a consequence, even slight changes in the page layout can break the wrapper and prevent it from extracting data correctly. Wrapper maintenance is a composite task that (i) verifies that the wrapper continues to extract data correctly from a source, and (ii) repairs the wrapper so that it works on the changed pages.
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Lerman, K., Knoblock, C.A. (2009). Wrapper Maintenance. In: LIU, L., ÖZSU, M.T. (eds) Encyclopedia of Database Systems. Springer, Boston, MA. https://doi.org/10.1007/978-0-387-39940-9_1158
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DOI: https://doi.org/10.1007/978-0-387-39940-9_1158
Publisher Name: Springer, Boston, MA
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