华为云云数据库GaussDBSynonym词典_云淘科技
Synonym词典用于定义、识别token的同义词并转化,不支持词组(词组形式的同义词可用Thesaurus词典定义,详细请参见Thesaurus词典)。
示例
Synonym词典可用于解决语言学相关问题,例如,为避免使单词”Paris”变成”pari”,可在Synonym词典文件中定义一行”Paris paris”,并将该词典放置在预定义的english_stem词典之前。
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gaussdb=# SELECT * FROM ts_debug('english', 'Paris'); alias | description | token | dictionaries | dictionary | lexemes -----------+-----------------+-------+----------------+--------------+--------- asciiword | Word, all ASCII | Paris | {english_stem} | english_stem | {pari} (1 row) gaussdb=# CREATE TEXT SEARCH DICTIONARY my_synonym ( TEMPLATE = synonym, SYNONYMS = my_synonyms, FILEPATH = 'file:///home/dicts/' ); gaussdb=# ALTER TEXT SEARCH CONFIGURATION english ALTER MAPPING FOR asciiword WITH my_synonym, english_stem; gaussdb=# SELECT * FROM ts_debug('english', 'Paris'); alias | description | token | dictionaries | dictionary | lexemes -----------+-----------------+-------+---------------------------+------------+--------- asciiword | Word, all ASCII | Paris | {my_synonym,english_stem} | my_synonym | {paris} (1 row) gaussdb=# SELECT * FROM ts_debug('english', 'paris'); alias | description | token | dictionaries | dictionary | lexemes -----------+-----------------+-------+---------------------------+------------+--------- asciiword | Word, all ASCII | Paris | {my_synonym,english_stem} | my_synonym | {paris} (1 row) gaussdb=# ALTER TEXT SEARCH DICTIONARY my_synonym ( CASESENSITIVE=true); gaussdb=# SELECT * FROM ts_debug('english', 'Paris'); alias | description | token | dictionaries | dictionary | lexemes -----------+-----------------+-------+---------------------------+------------+--------- asciiword | Word, all ASCII | Paris | {my_synonym,english_stem} | my_synonym | {paris} (1 row) gaussdb=# SELECT * FROM ts_debug('english', 'paris'); alias | description | token | dictionaries | dictionary | lexemes -----------+-----------------+-------+---------------------------+------------+--------- asciiword | Word, all ASCII | Paris | {my_synonym,english_stem} | my_synonym | {pari} (1 row) |
其中,同义词词典文件全名为my_synonyms.syn,所在目录为当前连接CN节点的/home/dicts/下。关于创建词典的语法和更多参数,请参见CREATE TEXT SEARCH DICTIONARY。
星号(*)可用于词典文件中的同义词结尾,表示该同义词是一个前缀。在to_tsvector()中该星号将被忽略,但在to_tsquery()中会匹配该前缀并对应输出结果(参照处理查询一节)。
假设词典文件synonym_sample.syn内容如下:
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gogle googl indices index* |
创建并使用词典:
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gaussdb=# CREATE TEXT SEARCH DICTIONARY syn ( TEMPLATE = synonym, SYNONYMS = synonym_sample ); gaussdb=# SELECT ts_lexize('syn','indices'); ts_lexize ----------- {index} (1 row) gaussdb=# CREATE TEXT SEARCH CONFIGURATION tst (copy=simple); gaussdb=# ALTER TEXT SEARCH CONFIGURATION tst ALTER MAPPING FOR asciiword WITH syn; gaussdb=# SELECT to_tsvector('tst','indices'); to_tsvector ------------- 'index':1 (1 row) gaussdb=# SELECT to_tsquery('tst','indices'); to_tsquery ------------ 'index':* (1 row) gaussdb=# SELECT 'indexes are very useful'::tsvector; tsvector --------------------------------- 'are' 'indexes' 'useful' 'very' (1 row) gaussdb=# SELECT 'indexes are very useful'::tsvector @@ to_tsquery('tst','indices'); ?column? ---------- t (1 row) |
父主题: 词典
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