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文本检索函数和操作符

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更新时间: 2019/06/24 GMT+08:00

文本检索操作符

  • @@

    描述:tsvector类型的词汇与tsquery类型的词汇是否匹配

    示例:

    SELECT to_tsvector('fat cats ate rats') @@ to_tsquery('cat & rat') AS RESULT;
     result 
    --------
     t
    (1 row)
  • @@@

    描述:@@的同义词

    示例:

    SELECT to_tsvector('fat cats ate rats') @@@ to_tsquery('cat & rat') AS RESULT;
     result 
    --------
     t
    (1 row)
  • ||

    描述:连接两个tsvector类型的词汇

    示例:

    SELECT 'a:1 b:2'::tsvector || 'c:1 d:2 b:3'::tsvector AS RESULT;
              result           
    ---------------------------
     'a':1 'b':2,5 'c':3 'd':4
    (1 row)
  • &&

    描述:将两个tsquery类型的词汇进行“与”操作

    示例:

    SELECT 'fat | rat'::tsquery && 'cat'::tsquery AS RESULT;
              result           
    ---------------------------
     ( 'fat' | 'rat' ) & 'cat'
    (1 row)
  • ||

    描述:将两个tsquery类型的词汇进行“或”操作

    示例:

    SELECT 'fat | rat'::tsquery || 'cat'::tsquery AS RESULT;
              result           
    ---------------------------
     ( 'fat' | 'rat' ) | 'cat'
    (1 row)
  • !!

    描述:tsquery类型词汇的非关系

    示例:

    SELECT !! 'cat'::tsquery AS RESULT;
     result 
    --------
     !'cat'
    (1 row)
  • @>

    描述:一个tsquery类型的词汇是否包含另一个tsquery类型的词汇

    示例:

    SELECT 'cat'::tsquery @> 'cat & rat'::tsquery AS RESULT;
     result 
    --------
     f
    (1 row)
  • <@

    描述:一个tsquery类型的词汇是否被包含另一个tsquery类型的词汇

    示例:

    SELECT 'cat'::tsquery <@ 'cat & rat'::tsquery AS RESULT;
     result 
    --------
     t
    (1 row)

除了上述的操作符,还为tsvector类型和tsquery类型的数据定义了普通的B-tree比较操作符(=,<等)。

文本检索函数

  • get_current_ts_config()

    描述:获取文本检索的默认配置。

    返回类型:regconfig

    示例:

    SELECT get_current_ts_config();
     get_current_ts_config 
    -----------------------
     english
    (1 row)
  • length(tsvector)

    描述:tsvector类型词汇的单词数。

    返回类型:integer

    示例:

    SELECT length('fat:2,4 cat:3 rat:5A'::tsvector);
     length 
    --------
          3
    (1 row)
  • numnode(tsquery)

    描述:tsquery类型的单词加上操作符的数量。

    返回类型:integer

    示例:

    SELECT numnode('(fat & rat) | cat'::tsquery);
     numnode 
    ---------
           5
    (1 row)
  • plainto_tsquery([ config regconfig , ] query text)

    描述:产生tsquery类型的词汇,并忽略标点

    返回类型:tsquery

    示例:

    SELECT plainto_tsquery('english', 'The Fat Rats');
     plainto_tsquery 
    -----------------
     'fat' & 'rat'
    (1 row)
  • querytree(query tsquery)

    描述:获取tsquery类型的词汇可加索引的部分。

    返回类型:text

    示例:

    SELECT querytree('foo & ! bar'::tsquery);
     querytree 
    -----------
     'foo'
    (1 row)
  • setweight(tsvector, "char")

    描述:给tsvector类型的每个元素分配权值。

    返回类型:tsvector

    示例:

    SELECT setweight('fat:2,4 cat:3 rat:5B'::tsvector, 'A');
               setweight           
    -------------------------------
     'cat':3A 'fat':2A,4A 'rat':5A
    (1 row)
  • strip(tsvector)

    描述:删除tsvector类型单词中的position和权值。

    返回类型:tsvector

    示例:

    SELECT strip('fat:2,4 cat:3 rat:5A'::tsvector);
           strip       
    -------------------
     'cat' 'fat' 'rat'
    (1 row)
  • to_tsquery([ config regconfig , ] query text)

    描述:标准化单词,并转换为tsquery类型。

    返回类型:tsquery

    示例:

    SELECT to_tsquery('english', 'The & Fat & Rats');
      to_tsquery   
    ---------------
     'fat' & 'rat'
    (1 row)
  • to_tsvector([ config regconfig , ] document text)

    描述:去除文件信息,并转换为tsvector类型。

    返回类型:tsvector

    示例:

    SELECT to_tsvector('english', 'The Fat Rats');
       to_tsvector   
    -----------------
     'fat':2 'rat':3
    (1 row)
  • ts_headline([ config regconfig, ] document text, query tsquery [, options text ])

    描述:高亮显示查询的匹配项。

    返回类型:text

    示例:

    SELECT ts_headline('x y z', 'z'::tsquery);
     ts_headline  
    --------------
     x y <b>z</b>
    (1 row)
  • ts_rank([ weights float4[], ] vector tsvector, query tsquery [, normalization integer ])

    描述:文档查询排名。

    返回类型:float4

    示例:

    SELECT ts_rank('hello world'::tsvector, 'world'::tsquery);
     ts_rank  
    ----------
     .0607927
    (1 row)
  • ts_rank_cd([ weights float4[], ] vector tsvector, query tsquery [, normalization integer ])

    描述:排序文件查询使用覆盖密度。

    返回类型:float4

    示例:

    SELECT ts_rank_cd('hello world'::tsvector, 'world'::tsquery);
     ts_rank_cd 
    ------------
              0
    (1 row)
  • ts_rewrite(query tsquery, target tsquery, substitute tsquery)

    描述:替换目标tsquery类型的单词。

    返回类型:tsquery

    示例:

    SELECT ts_rewrite('a & b'::tsquery, 'a'::tsquery, 'foo|bar'::tsquery);
           ts_rewrite        
    -------------------------
     'b' & ( 'foo' | 'bar' )
    (1 row)
  • ts_rewrite(query tsquery, select text)

    描述:使用SELECT命令的结果替代目标中tsquery类型的单词。

    返回类型:tsquery

    示例:

    SELECT ts_rewrite('world'::tsquery, 'select ''world''::tsquery, ''hello''::tsquery');
     ts_rewrite 
    ------------
     'hello'
    (1 row)

文本检索调试函数

  • ts_debug([ config regconfig, ] document text, OUT alias text, OUT description text, OUT token text, OUT dictionaries regdictionary[], OUT dictionary regdictionary, OUT lexemes text[])

    描述:测试一个配置。

    返回类型:setof record

    示例:

    SELECT ts_debug('english', 'The Brightest supernovaes');
                                         ts_debug                                      
    -----------------------------------------------------------------------------------
     (asciiword,"Word, all ASCII",The,{english_stem},english_stem,{})
     (blank,"Space symbols"," ",{},,)
     (asciiword,"Word, all ASCII",Brightest,{english_stem},english_stem,{brightest})
     (blank,"Space symbols"," ",{},,)
     (asciiword,"Word, all ASCII",supernovaes,{english_stem},english_stem,{supernova})
    (5 rows)
  • ts_lexize(dict regdictionary, token text)

    描述:测试一个数据字典。

    返回类型:text[]

    示例:

    SELECT ts_lexize('english_stem', 'stars');
     ts_lexize 
    -----------
     {star}
    (1 row)
  • ts_parse(parser_name text, document text, OUT tokid integer, OUT token text)

    描述:测试一个解析。

    返回类型:setof record

    示例:

    SELECT ts_parse('default', 'foo - bar');
     ts_parse  
    -----------
     (1,foo)
     (12," ")
     (12,"- ")
     (1,bar)
    (4 rows)
  • ts_parse(parser_oid oid, document text, OUT tokid integer, OUT token text)

    描述:测试一个解析。

    返回类型:setof record

    示例:

    SELECT ts_parse(3722, 'foo - bar');
     ts_parse  
    -----------
     (1,foo)
     (12," ")
     (12,"- ")
     (1,bar)
    (4 rows)
  • ts_token_type(parser_name text, OUT tokid integer, OUT alias text, OUT description text)

    描述:获取分析器定义的记号类型。

    返回类型:setof record

    示例:

    SELECT ts_token_type('default');
                            ts_token_type                         
    --------------------------------------------------------------
     (1,asciiword,"Word, all ASCII")
     (2,word,"Word, all letters")
     (3,numword,"Word, letters and digits")
     (4,email,"Email address")
     (5,url,URL)
     (6,host,Host)
     (7,sfloat,"Scientific notation")
     (8,version,"Version number")
     (9,hword_numpart,"Hyphenated word part, letters and digits")
     (10,hword_part,"Hyphenated word part, all letters")
     (11,hword_asciipart,"Hyphenated word part, all ASCII")
     (12,blank,"Space symbols")
     (13,tag,"XML tag")
     (14,protocol,"Protocol head")
     (15,numhword,"Hyphenated word, letters and digits")
     (16,asciihword,"Hyphenated word, all ASCII")
     (17,hword,"Hyphenated word, all letters")
     (18,url_path,"URL path")
     (19,file,"File or path name")
     (20,float,"Decimal notation")
     (21,int,"Signed integer")
     (22,uint,"Unsigned integer")
     (23,entity,"XML entity")
    (23 rows)
  • ts_token_type(parser_oid oid, OUT tokid integer, OUT alias text, OUT description text)

    描述:获取分析器定义的记号类型。

    返回类型:setof record

    示例:

    SELECT ts_token_type(3722);
                            ts_token_type                         
    --------------------------------------------------------------
     (1,asciiword,"Word, all ASCII")
     (2,word,"Word, all letters")
     (3,numword,"Word, letters and digits")
     (4,email,"Email address")
     (5,url,URL)
     (6,host,Host)
     (7,sfloat,"Scientific notation")
     (8,version,"Version number")
     (9,hword_numpart,"Hyphenated word part, letters and digits")
     (10,hword_part,"Hyphenated word part, all letters")
     (11,hword_asciipart,"Hyphenated word part, all ASCII")
     (12,blank,"Space symbols")
     (13,tag,"XML tag")
     (14,protocol,"Protocol head")
     (15,numhword,"Hyphenated word, letters and digits")
     (16,asciihword,"Hyphenated word, all ASCII")
     (17,hword,"Hyphenated word, all letters")
     (18,url_path,"URL path")
     (19,file,"File or path name")
     (20,float,"Decimal notation")
     (21,int,"Signed integer")
     (22,uint,"Unsigned integer")
     (23,entity,"XML entity")
    (23 rows)
  • ts_stat(sqlquery text, [ weights text, ] OUT word text, OUT ndoc integer, OUT nentry integer)

    描述:获取tsvector列的统计数据。

    返回类型:setof record

    示例:

    SELECT ts_stat('select ''hello world''::tsvector');
       ts_stat   
    -------------
     (world,1,1)
     (hello,1,1)
    (2 rows)
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