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Download Pro Full-Text Search in SQL Server 2008
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CHAPTER 8 ■ THESAURUSES Replacement Sets Replacement sets provide an alternative to expansion sets. Like expansion sets, replacement sets are defined using XML in the thesaurus files. Replacement sets also have the same 512-character limitation on terms. You can define replacement sets with <pat> and <sub> tags contained within a <replacement> tag. Though they’re defined in the same thesaurus files, replacement sets behave differently from expansion sets. While expansion sets automatically expand your search to include every search term in the set, replacement sets simply replace your search term with another search term per your definition. Where expansion sets are commonly used to define synonyms for words, replacement sets are useful for redefining acronyms and abbreviations in your searches. Replacement sets operate on search terms in the manner shown in Figure 8-4. Full-Text Index Replacement Set Search Term fl Replacement Patterns fl fla flor Sub Term florida Lorem m ipsum ips psum um dolor dol o or or sit s amet, consectetur ect cteet etur ad aadipisicing dipi pissic s elit, sed iuus usm smod te ttempor empo por o incididunt i do eiusmod ut ree et et dolore dol do oloore re magna mag aliqua. Ut labore m ad ad mi m inni nim m ve vveniam, enia quis en enim minim ruud ex eexercitation xer xe ercitta tat atiioon o ullamco nostrud riiss nisi nisi ut ut aaliquip liquip u ex ea laboris mod mo odo co cconsequat. ons on nse seq equat u Duis aute commodo dol oloor or in in reprehenderit repr preehe e irure dolor in Figure 8-4. Logical view of replacement set operation In Listing 8-1, we created the replacement set shown in Figure 8-4, replacing various search term abbreviations for Florida with the word florida, as shown: <replacement> <pat>fl</pat> <pat>fla</pat> <pat>flor</pat> <sub>florida</sub> </replacement> With this replacement set, performing a search for any of the defined abbreviations results in a search for the word florida. Note that the original search term is completely replaced in the search, so that the original search term is not included in the final search. Listing 8-9 shows a simple CONTAINS query with thesaurus replacement. Listing 8-9. CONTAINS Query with Thesaurus Replacement SELECT Book_ID FROM dbo.Book WHERE CONTAINS ( Book_Content, N'FORMSOF(THESAURUS, fl)' ); www.it-ebooks.info 175
