I need Lucene to keep some punctuation marks when indexing my texts, so I'm now using a WhitespaceAnalyzer which doesn't remove the symbols.
If there is a sentence like oranges, apples and bananas in the text, I want the phrase query "oranges, apples" to be a match (not without the comma), and this is working fine.
However, I'd also want the simple query oranges to produce a hit, but it seems the indexed token contains the comma too (oranges,) so it won't be a match unless I write the comma in the query too, which is undesirable.
Is there any simple way to make this work the way I need?
Thanks in advance.
I know this is a very old question, but I'm bored and I'll reply anyway. I see two ways of doing this:
Creating a TokenFilter that will create a synonym (e.g. insert a token into the stream with a 0 position length) each time a word contains punctuation with the non-puncuation version.
Add another field with the same content but using a standard tokenizer that removes all punctuation. Both fields will be matched.
Related
I am trying to pull 'COURSE_TITLE' column value from 'PS_TRAINING' table in PeopleSoft and writing into UTF-8 text file to get loaded into Workday system. The file is erroring out while loading because of bad characters(Ã â and many more) present in the column. I have used a procedure which will convert non-ascii value into space. But because of this procedure, the 'Course_Title' which are written in non-english language like Chinese, Korean, Spanish also replacing with spaces.
I even tried using regular expressions (``regexp_like(course_title, 'Ã) only to find bad characters but since the table has hundreds of thousands of rows, it would be difficult to find all bad characters. Please suggest a way to solve this.
If you change your approach, this may work.
Define what you want, and retrieve it.
select *
from PS_TRAINING
where not regexp_like(course_title, '[0-9A-Za-z]')```
If you take out too much data, just add it to the regex
I have an user input processor that transforms this search into "this" AND "search". My processor works great, it breaks the user input into pieces according to what I believe to be word breakers, which include punctuation.
The problem is that, while indexing, Sql Server applies a special approach when it comes to numbers.
if you index the following string:
12,20.1231,213.23,45,345.234.324.556,234.534.345
it will find the following index keys:
12
1231
20
213
23,45 (detected decimal separator)
234.534.345 (detected thousand separator)
345.234.324.556 (detected thousand separator)
Now, if the user searches for 324 he/she won't find anything, because 324 is contained within the last entry, not in the beggining, so it is not going to be found. I'd like it to stop treating numbers as numbers and just index it the way it does with words.
Is there a way to alter this behavior? without implementing too much code?
Not sure if I understand the question correctly, but if you say SQL is finding numbers, where it should find strings then casting them as strings seems to be the solution.
select cast(345234324556 as nvarchar)
I are trying to search an FTI using CONTAINS for Twitter-style usernames, e.g. #username, but word breakers will ignore the # symbol. Is there any way to disable word breakers? From research, there is a way to create a custom word breaker DLL and install it and assign it but that all seems a bit intensive and, frankly, over my head. I disabled stop words so that dashes are not ignored but I need that # symbol. Any ideas?
You're not going to like this answer. But full text indexes only consider the characters _ and ` while indexing. All the other characters are ignored and the words get split where these characters occur. This is mainly because full text indexes are designed to index large documents and there only proper words are considered to make it a more refined search.
We faced a similar problem. To solve this we actually had a translation table, where characters like #,-, / were replaced with special sequences like '`at`','`dash`','`slash`' etc. While searching in the full text, u've to again replace ur characters in the search string with these special sequences and search. This should take care of the special characters.
I have a database that has around 10k records and some of them contain HTML characters which I would like to replace.
For example I can find all occurrences:
SELECT * FROM TABLE
WHERE TEXTFIELD LIKE '%/%'
the original string example:
this is the cool mega string that contains /
how to replace all / with / ?
The end result should be:
this is the cool mega string that contains /
If you want to replace a specific string with another string or transformation of that string, you could use the "replace" function in postgresql. For instance, to replace all occurances of "cat" with "dog" in the column "myfield", you would do:
UPDATE tablename
SET myfield = replace(myfield,"cat", "dog")
You could add a WHERE clause or any other logic as you see fit.
Alternatively, if you are trying to convert HTML entities, ASCII characters, or between various encoding schemes, postgre has functions for that as well. Postgresql String Functions.
The answer given by #davesnitty will work, but you need to think very carefully about whether the text pattern you're replacing could appear embedded in a longer pattern you don't want to modify. Otherwise you'll find someone's nooking a fire, and that's just weird.
If possible, use a suitable dedicated tool for what you're un-escaping. Got URLEncoded text? use a url decoder. Got XML entities? Process them though an XSLT stylesheet in text mode output. etc. These are usually safer for your data than hacking it with find-and-replace, in that find and replace often has unfortunate side effects if not applied very carefully, as noted above.
It's possible you may want to use a regular expression. They are not a universal solution to all problems but are really handy for some jobs.
If you want to unconditionally replace all instances of "/" with "/", you don't need a regexp.
If you want to replace "/" but not "Ǘ", you might need a regexp, because you can do things like match only whole words, match various patterns, specify min/max runs of digits, etc.
In the PostgreSQL string functions and operators documentation you'll find the regexp_replace function, which will let you apply a regexp during an UPDATE statement.
To be able to say much more I'd need to know what your real data is and what you're really trying to do.
If you don't have postgres, you can export all database to a sql file, replace your string with a text editor and delete your db on your host, and re-import your new db
PS: be careful
I'm working on a search module that searches in text columns that contains html code. The queries are constructed like: WHERE htmlcolumn LIKE '% searchterm %';
Default the modules searches with spaces at both end of the searchterms, with wildcards at the beginning and/or the end of the searchterms these spaces are removed (*searchterm -> LIKE '%searchterm %'; Also i've added the possibility to exclude results with certain words (-searchterm -> NOT LIKE '% searchterm %'). So far so good.
The problem is that words that that are preceded by an html-tag are not found (<br/>searchterm is not found when searching on LIKE '% searchterm.., also words that come after a comma or end with a period etc.).
What i would like to do is search for words that are not preceded or followed by the characters A-Z and a-z. Every other characters are ok.
Any ideas how i should achieve this? Thanks!
Look into MySQLs fulltextsearch, it might be able to use non-letter characters as delimiters. It will alsow be much much faster than a %term% search since that requires a full table-scan.
You could use a regular expression: http://dev.mysql.com/doc/refman/5.0/en/regexp.html
Generally speaking, it is better to use full text search facilities, but if you really want a small SQL, here it is:
SELECT * FROM `t` WHERE `htmlcolumn` REGEXP '[[:<:]]term[[:>:]]'
It returns all records that contain word 'term' whether it is surrounded with spaces, punctuation, special characters etc
I don't think SQL's "LIKE" operator alone is the right tool for the job you are trying to do. Consider using Lucene, or something like it. I was able to integrate Lucene.NET into my application in a couple days. You'll spend more time than that trying to salvage your current approach.
If you have no choice but to make your current approach work, then consider storing the text in two columns in your database. The first column is for the pure text, with punctuation etc. The second column is the text that has been pre-preprocessed, just words, no punctuation, normalized so as to be easier for your "LIKE" approach.