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docs: remove use of escape strings and use bytea hex output

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standard_conforming_strings defaulted to 'on' in PG 9.1.
bytea_output defaulted to 'hex' in PG 9.0.

Reported-by: André Hänsel

Discussion: https://postgr.es/m/12e601d447ac$345994a0$9d0cbde0$@webkr.de

Backpatch-through: 9.3
This commit is contained in:
Bruce Momjian
2018-09-21 19:55:07 -04:00
parent 45a2d45f4f
commit 7f203d60f4
5 changed files with 72 additions and 80 deletions
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27
doc/src/sgml/array.sgml
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@ -766,9 +766,9 @@ SELECT f1[1][-2][3] AS e1, f1[1][-1][5] AS e2
For example, elements containing curly braces, commas (or the data type's
delimiter character), double quotes, backslashes, or leading or trailing
whitespace must be double-quoted. Empty strings and strings matching the
word <literal>NULL</literal> must be quoted, too. To put a double quote or
backslash in a quoted array element value, use escape string syntax
and precede it with a backslash. Alternatively, you can avoid quotes and use
word <literal>NULL</literal> must be quoted, too. To put a double
quote or backslash in a quoted array element value, precede it
with a backslash. Alternatively, you can avoid quotes and use
backslash-escaping to protect all data characters that would otherwise
be taken as array syntax.
</para>
@ -781,27 +781,6 @@ SELECT f1[1][-2][3] AS e1, f1[1][-1][5] AS e2
non-whitespace characters of an element, is not ignored.
</para>
<note>
<para>
Remember that what you write in an SQL command will first be interpreted
as a string literal, and then as an array. This doubles the number of
backslashes you need. For example, to insert a <type>text</type> array
value containing a backslash and a double quote, you'd need to write:
<programlisting>
INSERT ... VALUES (E'{"\\\\","\\""}');
</programlisting>
The escape string processor removes one level of backslashes, so that
what arrives at the array-value parser looks like <literal>{"\\","\""}</literal>.
In turn, the strings fed to the <type>text</type> data type's input routine
become <literal>\</literal> and <literal>"</literal> respectively. (If we were working
with a data type whose input routine also treated backslashes specially,
<type>bytea</type> for example, we might need as many as eight backslashes
in the command to get one backslash into the stored array element.)
Dollar quoting (see <xref linkend="sql-syntax-dollar-quoting"/>) can be
used to avoid the need to double backslashes.
</para>
</note>
<tip>
<para>
The <literal>ARRAY</literal> constructor syntax (see