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mysql全文索引之停止词(stopword)

2014-08-18 08:21 来源: IT技术学习网 阅读:

本文IT技术学习网将给大家讲述什么是mysql全文索引中的停止词(stopword也有的翻译做停止字)。

stopword

在全文索引中,如果一个词被认为是太普通或者太没价值,那么它将会被搜索索引和搜索查询忽略。innodb和myisam分别有两组不同的设置,控制着对应的stopword。

全文检索时,停止词列表将会被读取和检索,在不同的字符集和排序方式下(character_set_server and collation_server 系统变量),可能会导致在搜索时的停止词的不匹配。

停止词是否大小写敏感,取决于不同的排序方式,比如:latin1_swedish_ci下停止词是大小写敏感的,latin1_general_cs 或 latin1_bin下停止词是大小写不敏感的。

innodb的索引停止词

innodb的默认停止词列表很短。查询INFORMATION_SCHEMA.INNODB_FT_DEFAULT_STOPWORD表来查看默认的innodb停止词表。

    mysql> SELECT * FROM INFORMATION_SCHEMA.INNODB_FT_DEFAULT_STOPWORD;
    +-------+
    | value |
    +-------+
    | a     |
    | about |
    | an    |
    | are   |
    | as    |
    | at    |
    | be    |
    | by    |
    | com   |
    | de    |
    | en    |
    | for   |
    | from  |
    | how   |
    | i     |
    | in    |
    | is    |
    | it    |
    | la    |
    | of    |
    | on    |
    | or    |
    | that  |
    | the   |
    | this  |
    | to    |
    | was   |
    | what  |
    | when  |
    | where |
    | who   |
    | will  |
    | with  |
    | und   |
    | the   |
    | www   |
    +-------+
    36 rows in set (0.00 sec)

myisam索引的停止词

myisam索引的停止词列表与innodb不同,默认的myisam停止词列表是直接在mysql程序源码中已写入。设置ft_stopword_file系统变量来指定停止词文件,从而覆盖默认设置。

在mysql源程序的 storage/myisam/ft_static.c file文件中,你可以找到默认的myisam停止词列表:

    a's able about above according
    accordingly across actually after afterwards
    again against ain't all allow
    allows almost alone along already
    also although always am among
    amongst an and another any
    anybody anyhow anyone anything anyway
    anyways anywhere apart appear appreciate
    appropriate are aren't around as
    aside ask asking associated at
    available away awfully be became
    because become becomes becoming been
    before beforehand behind being believe
    below beside besides best better
    between beyond both brief but
    by c'mon c's came can
    can't cannot cant cause causes
    certain certainly changes clearly co
    com come comes concerning consequently
    consider considering contain containing contains
    corresponding could couldn't course currently
    definitely described despite did didn't
    different do does doesn't doing
    don't done down downwards during
    each edu eg eight either
    else elsewhere enough entirely especially
    et etc even ever every
    everybody everyone everything everywhere ex
    exactly example except far few
    fifth first five followed following
    follows for former formerly forth
    four from further furthermore get
    gets getting given gives go
    goes going gone got gotten
    greetings had hadn't happens hardly
    has hasn't have haven't having
    he he's hello help hence
    her here here's hereafter hereby
    herein hereupon hers herself hi
    him himself his hither hopefully
    how howbeit however i'd i'll
    i'm i've ie if ignored
    immediate in inasmuch inc indeed
    indicate indicated indicates inner insofar
    instead into inward is isn't
    it it'd it'll it's its
    itself just keep keeps kept
    know known knows last lately
    later latter latterly least less
    lest let let's like liked
    likely little look looking looks
    ltd mainly many may maybe
    me mean meanwhile merely might
    more moreover most mostly much
    must my myself name namely
    nd near nearly necessary need
    needs neither never nevertheless new
    next nine no nobody non
    none noone nor normally not
    nothing novel now nowhere obviously
    of off often oh ok
    okay old on once one
    ones only onto or other
    others otherwise ought our ours
    ourselves out outside over overall
    own particular particularly per perhaps
    placed please plus possible presumably
    probably provides que quite qv
    rather rd re really reasonably
    regarding regardless regards relatively respectively
    right said same saw say
    saying says second secondly see
    seeing seem seemed seeming seems
    seen self selves sensible sent
    serious seriously seven several shall
    she should shouldn't since six
    so some somebody somehow someone
    something sometime sometimes somewhat somewhere
    soon sorry specified specify specifying
    still sub such sup sure
    t's take taken tell tends
    th than thank thanks thanx
    that that's thats the their
    theirs them themselves then thence
    there there's thereafter thereby therefore
    therein theres thereupon these they
    they'd they'll they're they've think
    third this thorough thoroughly those
    though three through throughout thru
    thus to together too took
    toward towards tried tries truly
    try trying twice two un
    under unfortunately unless unlikely until
    unto up upon us use
    used useful uses using usually
    value various very via viz
    vs want wants was wasn't
    way we we'd we'll we're
    we've welcome well went were
    weren't what what's whatever when
    whence whenever where where's whereafter
    whereas whereby wherein whereupon wherever
    whether which while whither who
    who's whoever whole whom whose
    why will willing wish with
    within without won't wonder would
    wouldn't yes yet you you'd
    you'll you're you've your yours
    yourself yourselves zero



mysql全文索引之停止词(stopword)
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