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Unicode escapes in E'...' strings

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Author: Marko Kreen <markokr@gmail.com>
This commit is contained in:
Peter Eisentraut
2009-09-22 23:52:53 +00:00
parent 9048b73184
commit c2bb0378cf
3 changed files with 98 additions and 9 deletions
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34
doc/src/sgml/syntax.sgml
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@ -1,4 +1,4 @@
<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.135 2009/09/21 22:22:07 petere Exp $ -->
<!-- $PostgreSQL: pgsql/doc/src/sgml/syntax.sgml,v 1.136 2009/09/22 23:52:53 petere Exp $ -->
<chapter id="sql-syntax">
<title>SQL Syntax</title>
@ -398,6 +398,14 @@ SELECT 'foo' 'bar';
</entry>
<entry>hexadecimal byte value</entry>
</row>
<row>
<entry>
<literal>\u<replaceable>xxxx</replaceable></literal>,
<literal>\U<replaceable>xxxxxxxx</replaceable></literal>
(<replaceable>x</replaceable> = 0 - 9, A - F)
</entry>
<entry>16 or 32-bit hexadecimal Unicode character value</entry>
</row>
</tbody>
</tgroup>
</table>
@ -411,13 +419,25 @@ SELECT 'foo' 'bar';
</para>
<para>
It is your responsibility that the byte sequences you create are
It is your responsibility that the byte sequences you create,
especially when using the octal or hexadecimal escapes, compose
valid characters in the server character set encoding. When the
server encoding is UTF-8, then the alternative Unicode escape
syntax, explained in <xref linkend="sql-syntax-strings-uescape">,
should be used instead. (The alternative would be doing the
UTF-8 encoding by hand and writing out the bytes, which would be
very cumbersome.)
server encoding is UTF-8, then the Unicode escapes or the
alternative Unicode escape syntax, explained
in <xref linkend="sql-syntax-strings-uescape">, should be used
instead. (The alternative would be doing the UTF-8 encoding by
hand and writing out the bytes, which would be very cumbersome.)
</para>
<para>
The Unicode escape syntax works fully only when the server
encoding is UTF-8. When other server encodings are used, only
code points in the ASCII range (up to <literal>\u007F</>) can be
specified. Both the 4-digit and the 8-digit form can be used to
specify UTF-16 surrogate pairs to compose characters with code
points larger than <literal>\FFFF</literal> (although the
availability of the 8-digit form technically makes this
unnecessary).
</para>
<caution>