diff options
Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/charset.sgml | 10 | ||||
| -rw-r--r-- | doc/src/sgml/func.sgml | 48 |
2 files changed, 58 insertions, 0 deletions
diff --git a/doc/src/sgml/charset.sgml b/doc/src/sgml/charset.sgml index 20cdfabd7bf..b6023fa459e 100644 --- a/doc/src/sgml/charset.sgml +++ b/doc/src/sgml/charset.sgml @@ -934,6 +934,16 @@ CREATE COLLATION ignore_accents (provider = icu, locale = 'und-u-ks-level1-kc-tr such as pattern matching operations. Therefore, they should be used only in cases where they are specifically wanted. </para> + + <tip> + <para> + To deal with text in different Unicode normalization forms, it is also + an option to use the functions/expressions + <function>normalize</function> and <literal>is normalized</literal> to + preprocess or check the strings, instead of using nondeterministic + collations. There are different trade-offs for each approach. + </para> + </tip> </sect3> </sect2> </sect1> diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index cbfd2a762e4..a329f61f339 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -1563,6 +1563,30 @@ <row> <entry> <indexterm> + <primary>normalized</primary> + </indexterm> + <indexterm> + <primary>Unicode normalization</primary> + </indexterm> + <literal><parameter>string</parameter> is <optional>not</optional> <optional><parameter>form</parameter></optional> normalized</literal> + </entry> + <entry><type>boolean</type></entry> + <entry> + Checks whether the string is in the specified Unicode normalization + form. The optional parameter specifies the form: + <literal>NFC</literal> (default), <literal>NFD</literal>, + <literal>NFKC</literal>, <literal>NFKD</literal>. This expression can + only be used if the server encoding is <literal>UTF8</literal>. Note + that checking for normalization using this expression is often faster + than normalizing possibly already normalized strings. + </entry> + <entry><literal>U&'\0061\0308bc' IS NFD NORMALIZED</literal></entry> + <entry><literal>true</literal></entry> + </row> + + <row> + <entry> + <indexterm> <primary>bit_length</primary> </indexterm> <literal><function>bit_length(<parameter>string</parameter>)</function></literal> @@ -1613,6 +1637,30 @@ <row> <entry> <indexterm> + <primary>normalize</primary> + </indexterm> + <indexterm> + <primary>Unicode normalization</primary> + </indexterm> + <literal><function>normalize(<parameter>string</parameter> <type>text</type> + <optional>, <parameter>form</parameter> </optional>)</function></literal> + </entry> + <entry><type>text</type></entry> + <entry> + Converts the string in the first argument to the specified Unicode + normalization form. The optional second argument specifies the form + as an identifier: <literal>NFC</literal> (default), + <literal>NFD</literal>, <literal>NFKC</literal>, + <literal>NFKD</literal>. This function can only be used if the server + encoding is <literal>UTF8</literal>. + </entry> + <entry><literal>normalize(U&'\0061\0308bc', NFC)</literal></entry> + <entry><literal>U&'\00E4bc'</literal></entry> + </row> + + <row> + <entry> + <indexterm> <primary>octet_length</primary> </indexterm> <literal><function>octet_length(<parameter>string</parameter>)</function></literal> |