What is a inverted index? Inverted table? How do I establish an inverted index?

Source: Internet
Author: User

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Why do we say inverted index?


because inverted index is the most commonly used storage method of search engine company. It is also the core content of search engine!


in the actual reference of the search engine, sometimes it is necessary to find records by some value of the keyword, so we are indexed by keyword, which we call: Inverted index, and a file with inverted index we call it: Inverted index file can also be called: Inverted file To achieve fast retrieval and high-speed efficiency!





then I would like to ask what is the inverted table?


index of secondary key in inverted file we call it: Inverted table


Its main advantage is: in the processing of complex multiple keyword query, can be in the inverted table to complete the query of the intersection, and other logical operations, the results of the access to the record. This eliminates the need for random access to each record, converting the query to the records into the operation of the address set, thus improving the lookup speed!





below is the entire inverted table establishment process (PHOTOS):





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Index Table


 


Index Table after merging right item


 


then let me ask the last question, how do we build an inverted index?


about setting up inverted indexes It's like we're writing a novel. The Table of contents is the page number of the chapter title The inverted index is the corresponding document number for Full-text search!


Here's an example:


Case 1:


Normal document existence form:


PPT (look from the beginning ...) ==> KEYWORDS1,KEYWORDS2,KEYWORDS3,KEYWORDS4,KEYWORDS5,.............


Case 2:


Inverted Index rollover results show:


KEYWORDS1,KEYWORDS2,KEYWORDS3,KEYWORDS4,KEYWORDS5,............. (Find the keyword and then find the content page) ==> PPT





don't know if you understand! If it's not clear, I'm just saying, for example, the simplest:


we read any book, I think it's a 2-way idea. And the other is to look at the table of contents to see what I need to see so directly to the page!  Or you're going to look like the first person. See what you want to see that's not the time wasted?? The directory plays a key role! It's time to understand! If it's not clear, look at the inverted table above.  If you do not understand or do not understand that you can contact me. Contact See the bottom of the page!


from Shanghai SEO http://www.seo-sh.cn QQ 10171718 SWJ
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