diff options
| -rw-r--r-- | doc/src/sgml/charset.sgml | 58 | ||||
| -rw-r--r-- | doc/src/sgml/ref/create_collation.sgml | 13 | ||||
| -rw-r--r-- | doc/src/sgml/ref/create_database.sgml | 4 |
3 files changed, 62 insertions, 13 deletions
diff --git a/doc/src/sgml/charset.sgml b/doc/src/sgml/charset.sgml index dd092fddd61..25febcac4c0 100644 --- a/doc/src/sgml/charset.sgml +++ b/doc/src/sgml/charset.sgml @@ -1481,7 +1481,7 @@ SELECT 'x-y' = 'x_y' COLLATE level4; -- false </sect3> <sect3 id="icu-locale-examples"> - <title>Examples</title> + <title>Collation Settings Examples</title> <variablelist> <varlistentry id="collation-managing-create-icu-de-u-co-phonebk-x-icu"> @@ -1530,6 +1530,62 @@ SELECT 'x-y' = 'x_y' COLLATE level4; -- false </variablelist> </sect3> + <sect3 id="icu-tailoring-rules"> + <title>ICU Tailoring Rules</title> + + <para> + If the options provided by the collation settings shown above are not + sufficient, the order of collation elements can be changed with tailoring + rules, whose syntax is detailed at <ulink + url="https://unicode-org.github.io/icu/userguide/collation/customization/"></ulink>. + </para> + + <para> + This small example creates a collation based on the root locale with a + tailoring rule: +<programlisting> +<![CDATA[CREATE COLLATION custom (provider = icu, locale = 'und', rules = '&V << w <<< W');]]> +</programlisting> + With this rule, the letter <quote>W</quote> is sorted after + <quote>V</quote>, but is treated as a secondary difference similar to an + accent. Rules like this are contained in the locale definitions of some + languages. (Of course, if a locale definition already contains the + desired rules, then they don't need to be specified again explicitly.) + </para> + + <para> + Here is a more complex example. The following statement sets up a + collation named <literal>ebcdic</literal> with rules to sort US-ASCII + characters in the order of the EBCDIC encoding. + +<programlisting> +<![CDATA[CREATE COLLATION ebcdic (provider = icu, locale = 'und', +rules = $$ +& ' ' < '.' < '<' < '(' < '+' < \| +< '&' < '!' < '$' < '*' < ')' < ';' +< '-' < '/' < ',' < '%' < '_' < '>' < '?' +< '`' < ':' < '#' < '@' < \' < '=' < '"' +<*a-r < '~' <*s-z < '^' < '[' < ']' +< '{' <*A-I < '}' <*J-R < '\' <*S-Z <*0-9 +$$);]]> + +SELECT c +FROM (VALUES ('a'), ('b'), ('A'), ('B'), ('1'), ('2'), ('!'), ('^')) AS x(c) +ORDER BY c COLLATE ebcdic; + c +--- + ! + a + b + ^ + A + B + 1 + 2 +</programlisting> + </para> + </sect3> + <sect3 id="icu-external-references"> <title>External References for ICU</title> diff --git a/doc/src/sgml/ref/create_collation.sgml b/doc/src/sgml/ref/create_collation.sgml index b86a9bbb9ce..5cf9777764b 100644 --- a/doc/src/sgml/ref/create_collation.sgml +++ b/doc/src/sgml/ref/create_collation.sgml @@ -165,9 +165,8 @@ CREATE COLLATION [ IF NOT EXISTS ] <replaceable>name</replaceable> FROM <replace <listitem> <para> Specifies additional collation rules to customize the behavior of the - collation. This is supported for ICU only. See <ulink - url="https://unicode-org.github.io/icu/userguide/collation/customization/"/> - for details on the syntax. + collation. This is supported for ICU only. See <xref + linkend="icu-tailoring-rules"/> for details. </para> </listitem> </varlistentry> @@ -257,12 +256,8 @@ CREATE COLLATION german_phonebook (provider = icu, locale = 'de-u-co-phonebk'); <programlisting> <![CDATA[CREATE COLLATION custom (provider = icu, locale = 'und', rules = '&V << w <<< W');]]> </programlisting> - With this rule, the letter <quote>W</quote> is sorted after - <quote>V</quote>, but is treated as a secondary difference similar to an - accent. Rules like this are contained in the locale definitions of some - languages. (Of course, if a locale definition already contains the desired - rules, then they don't need to be specified again explicitly.) See the ICU - documentation for further details and examples on the rules syntax. + See <xref linkend="icu-tailoring-rules"/> for further details and examples + on the rules syntax. </para> <para> diff --git a/doc/src/sgml/ref/create_database.sgml b/doc/src/sgml/ref/create_database.sgml index b2c8aef1ad2..ce7317f81ba 100644 --- a/doc/src/sgml/ref/create_database.sgml +++ b/doc/src/sgml/ref/create_database.sgml @@ -232,9 +232,7 @@ CREATE DATABASE <replaceable class="parameter">name</replaceable> <para> Specifies additional collation rules to customize the behavior of the default collation of this database. This is supported for ICU only. - See <ulink - url="https://unicode-org.github.io/icu/userguide/collation/customization/"/> - for details on the syntax. + See <xref linkend="icu-tailoring-rules"/> for details. </para> </listitem> </varlistentry> |