Kouhei Sutou
null+****@clear*****
Mon May 29 21:37:15 JST 2017
Kouhei Sutou 2017-05-29 21:37:15 +0900 (Mon, 29 May 2017) New Revision: 67ce096dd65976b6291b2287541f03d0604cd453 https://github.com/pgroonga/pgroonga.github.io/commit/67ce096dd65976b6291b2287541f03d0604cd453 Message: Document &~ Copied files: reference/operators/regular-expression-v2.md (from reference/operators/regular-expression.md) Modified files: reference/operators/regular-expression.md Copied: reference/operators/regular-expression-v2.md (+10 -10) 89% =================================================================== --- reference/operators/regular-expression.md 2017-05-29 16:44:50 +0900 (73afdac) +++ reference/operators/regular-expression-v2.md 2017-05-29 21:37:15 +0900 (56264c2) @@ -1,13 +1,13 @@ --- -title: "@~ operator" +title: "&~ operator" upper_level: ../ --- -# `@~` operator +# `&~` operator ## Summary -`@~` operator performs regular expression search. +`&~` operator performs regular expression search. PostgreSQL provides the following built-in regular expression operators: @@ -17,9 +17,9 @@ PostgreSQL provides the following built-in regular expression operators: `SIMILAR TO` is based on SQL standard. "POSIX Regular Expression" is based on POSIX. They use different regular expression syntax. -PGroonga's `@~` operator uses another regular expression syntax. `@~` uses syntax that is used in [Ruby](https://www.ruby-lang.org/). Because PGroonga uses the same regular expression engine that is used in Ruby. It's [Onigmo](https://github.com/k-takata/Onigmo). See [Onigmo document](https://github.com/k-takata/Onigmo/blob/master/doc/RE) for full syntax definition. +PGroonga's `&~` operator uses another regular expression syntax. `&~` uses syntax that is used in [Ruby](https://www.ruby-lang.org/). Because PGroonga uses the same regular expression engine that is used in Ruby. It's [Onigmo](https://github.com/k-takata/Onigmo). See [Onigmo document](https://github.com/k-takata/Onigmo/blob/master/doc/RE) for full syntax definition. -PGroonga's `@~` operator normalizes target text before matching. It's similar to `~*` operator in "POSIX Regular Expression". It performs case insensitive match. +PGroonga's `&~` operator normalizes target text before matching. It's similar to `~*` operator in "POSIX Regular Expression". It performs case insensitive match. Normalization is different from case insensitive. Normally, normalization is more powerful. @@ -27,7 +27,7 @@ Example1: All of "`A`", "`a`", "`Ａ`" (U+FF21 FULLWIDTH LATIN CAPITAL LETTER A) Example2: Both of full-width Katakana and half-width Katakana are normalized to full-width Katakana. For example, both of "`ア`" (U+30A2 KATAKANA LETTER A) and "`ｱ`" (U+FF71 HALFWIDTH KATAKANA LETTER A) are normalized to "`ア`" (U+30A2 KATAKANA LETTER A). -Note that `@~` operator doesn't normalize regular expression pattern. It only normalizes target text. It means that you must use normalized characters in regular expression pattern. +Note that `&~` operator doesn't normalize regular expression pattern. It only normalizes target text. It means that you must use normalized characters in regular expression pattern. For example, you must not use "`Groonga`" as pattern. You must use "`groonga`" as pattern. Because "`G`" in target text is normalized to "`g`". "`Groonga`" is never appeared in target text. @@ -40,7 +40,7 @@ Note that Groonga may search with regular expression pattern by sequential scan ## Syntax ```sql -column @~ regular_expression +column &~ regular_expression ``` `column` is a column to be searched. @@ -86,10 +86,10 @@ INSERT INTO memos VALUES (3, 'PGroonga is a PostgreSQL extension that uses Groon INSERT INTO memos VALUES (4, 'There is groonga command.'); ``` -You can perform regular expression search by `@~` operator: +You can perform regular expression search by `&~` operator: ```sql -SELECT * FROM memos WHERE content @~ '\Apostgresql'; +SELECT * FROM memos WHERE content &~ '\Apostgresql'; -- id | content -- ----+-------------------------------------------------------- -- 1 | PostgreSQL is a relational database management system. @@ -98,7 +98,7 @@ SELECT * FROM memos WHERE content @~ '\Apostgresql'; "`\A`" in "`\Apostgresql`" is a special notation in Ruby regular expression syntax. It means that the beginning of text. The pattern means that "`postgresql`" must be appeared in the beginning of text. -Why is "`PostgreSQL is a ...`" record matched? Remember that `@~` operator normalizes target text before matching. It means that "`PostgreSQL is a ...`" text is normalized to "`postgresql is a ...`" text before matching. The normalized text is started with "`postgresql`". So "`\Apostgresql`" regular expression matches to the record. +Why is "`PostgreSQL is a ...`" record matched? Remember that `&~` operator normalizes target text before matching. It means that "`PostgreSQL is a ...`" text is normalized to "`postgresql is a ...`" text before matching. The normalized text is started with "`postgresql`". So "`\Apostgresql`" regular expression matches to the record. "`PGroonga is a PostgreSQL ...`" record isn't matched. It includes "`postgresql`" in normalized text but "`postgresql`" isn't appeared at the beginning of text. So it's not matched. Modified: reference/operators/regular-expression.md (+4 -0) =================================================================== --- reference/operators/regular-expression.md 2017-05-29 16:44:50 +0900 (73afdac) +++ reference/operators/regular-expression.md 2017-05-29 21:37:15 +0900 (eb03d88) @@ -7,6 +7,8 @@ upper_level: ../ ## Summary +This operator is deprecated since 1.2.0. Use [`&~` operator](regular-expression-v2.html) instead. + `@~` operator performs regular expression search. PostgreSQL provides the following built-in regular expression operators: @@ -107,3 +109,5 @@ Why is "`PostgreSQL is a ...`" record matched? Remember that `@~` operator norma * [Onigmo's regular expression syntax document](https://github.com/k-takata/Onigmo/blob/master/doc/RE) * [Groonga's regular expression support document](http://groonga.org/docs/reference/regular_expression.html) + + * [`&~` operator](regular-expression-v2.html) -------------- next part -------------- HTML����������������������������...다운로드
