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Topic: Database Search (Read 8723 times) |
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mad
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Database Search
« on: Feb 5th, 2008, 5:56am » |
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How do you search for a word in a large database?
Suggest efficient data structures, algorithms or indices for the same.
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Grimbal
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Re: Database Search
« Reply #1 on: Feb 5th, 2008, 6:13am » |
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Is the question like: how to implement a database?
What kind of database is it? Is it like a dictionary and you search the definition of a word, or is it like a documents database and you search where the word appears?
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mad
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Re: Database Search
« Reply #2 on: Feb 6th, 2008, 9:53am » |
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Say it is a database of documents and you search where the word appears
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Grimbal
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Re: Database Search
« Reply #3 on: Feb 6th, 2008, 10:08am » |
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Create for each word the list of documents where it appears.
It is quite easy. Create one file for each word. The file being conveniently named after the file. Parse all the documents, and every time you find a word you write the name of the document in the file.
Well, maybe you should first remove duplicates from the document.
So: for each document, parse the document and store a list of unique words in a hash table. Then, for each word, append the ID fo the document at the end of the file named after the word. Create the files as necessary.
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| « Last Edit: Feb 6th, 2008, 10:09am by Grimbal » |
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iatkrox
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Re: Database Search
« Reply #4 on: Jul 2nd, 2012, 9:49am » |
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Make a search bot !!! Then he will do the work for you 
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kylajams
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Re: Database Search
« Reply #5 on: Aug 27th, 2012, 3:35am » |
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Even I wish to know the answer.
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kentonson
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Re: Database Search
« Reply #6 on: Nov 7th, 2012, 8:11am » |
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Any new algorithm for searching  I wish to know well ...
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cartoonle
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Re: Database Search
« Reply #7 on: Dec 13th, 2012, 4:01am » |
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You should build a inverted index like search engines do. The best for this job are NoSQL databases like Big table from Google.
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friv - something i've built
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webtasarim
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Re: Database Search
« Reply #8 on: Oct 6th, 2013, 4:40pm » |
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i m gonna use simple words
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pratisaad
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Re: Database Search
« Reply #9 on: Oct 10th, 2013, 5:17am » |
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Microsoft SQL is the good database for security purpose.
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Grimbal
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Re: Database Search
« Reply #11 on: Oct 10th, 2013, 3:07pm » |
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Yeah, but if it's Microsoft who asks at a job interview...
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| « Last Edit: Oct 10th, 2013, 3:07pm by Grimbal » |
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webtasarim
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Re: Database Search
« Reply #12 on: Oct 21st, 2013, 3:42am » |
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binary search algorithm can be the best one .
In computer science, a binary search or half-interval search algorithm finds the position of a specified input value (the search "key") within an array sorted by key value.[1][2] In each step, the algorithm compares the search key value with the key value of the middle element of the array. If the keys match, then a matching element has been found and its index, or position, is returned. Otherwise, if the search key is less than the middle element's key, then the algorithm repeats its action on the sub-array to the left of the middle element or, if the search key is greater, on the sub-array to the right. If the remaining array to be searched is empty, then the key cannot be found in the array and a special "not found" indication is returned.
A binary search halves the number of items to check with each iteration, so locating an item (or determining its absence) takes logarithmic time. A binary search is a dichotomic divide and conquer search algorithm.
source : wikipedia.org
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Grimbal
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Re: Database Search
« Reply #13 on: Oct 21st, 2013, 4:35am » |
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Binary search is useless in locating occurences of a word in a set of documents.
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