Kazuhiko
kazuh****@fdiar*****
2014年 9月 24日 (水) 18:19:45 JST
こんにちは、かずひこです。 Boolean Modeにおける*の仕様について疑問があります。 http://mroonga.org/ja/docs/reference/full_text_search/boolean_mode.html には、 The asterisk serves as the truncation (or wildcard) operator. とありますが、前方一致、後方一致、中間一致のどれでも使えるものでしょうか？ 以下、TokenBigramでの例です。 > SELECT *, MATCH (content) AGAINST ("to*" in boolean mode) AS score FROM diaries; +----+--------------------------------------------------+-------+ | id | content | score | +----+--------------------------------------------------+-------+ | 1 | It'll be fine tomorrow as well. | 1 | | 2 | It'll rain tomorrow. | 1 | | 3 | It's fine today. It'll be fine tomorrow as well. | 2 | | 4 | It's fine today. But it'll rain tomorrow. | 2 | | 5 | Ring the bell. | 0 | | 6 | I love dumbbells. | 0 | +----+--------------------------------------------------+-------+ 期待通り、'to*'がtodayにもtomorrowにもヒットしているようです。 > SELECT *, MATCH (content) AGAINST ("*day" in boolean mode) AS score FROM diaries; +----+--------------------------------------------------+-------+ | id | content | score | +----+--------------------------------------------------+-------+ | 1 | It'll be fine tomorrow as well. | 1 | | 2 | It'll rain tomorrow. | 1 | | 3 | It's fine today. It'll be fine tomorrow as well. | 1 | | 4 | It's fine today. But it'll rain tomorrow. | 1 | | 5 | Ring the bell. | 0 | | 6 | I love dumbbells. | 0 | +----+--------------------------------------------------+-------+ '*day'がid=1やid=2にヒットするのは何故でしょうか？ ちなみに > SELECT *, MATCH (content) AGAINST ("*" in boolean mode) AS score FROM diaries; +----+--------------------------------------------------+-------+ | id | content | score | +----+--------------------------------------------------+-------+ | 1 | It'll be fine tomorrow as well. | 1 | | 2 | It'll rain tomorrow. | 1 | | 3 | It's fine today. It'll be fine tomorrow as well. | 1 | | 4 | It's fine today. But it'll rain tomorrow. | 1 | | 5 | Ring the bell. | 0 | | 6 | I love dumbbells. | 0 | +----+--------------------------------------------------+-------+ '*'だけの結果も全く同じになりました。 Boolean Modeでの'*'の期待される仕様や制限について教えてくださると幸いです。 かずひこ
