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postgresql
7th chunk of `doc/src/sgml/rowtypes.sgml`
b5b3eb8329901b46a6d70e6fc1d80b0dfc852b492e96c35800000001000007e8
 way to force the function interpretation in
    older versions is to schema-qualify the function name, that is, write
    <literal><replaceable>schema</replaceable>.<replaceable>func</replaceable>(<replaceable>compositevalue</replaceable>)</literal>.
   </para>
  </tip>
 </sect2>

 <sect2 id="rowtypes-io-syntax">
  <title>Composite Type Input and Output Syntax</title>

  <para>
   The external text representation of a composite value consists of items that
   are interpreted according to the I/O conversion rules for the individual
   field types, plus decoration that indicates the composite structure.
   The decoration consists of parentheses (<literal>(</literal> and <literal>)</literal>)
   around the whole value, plus commas (<literal>,</literal>) between adjacent
   items.  Whitespace outside the parentheses is ignored, but within the
   parentheses it is considered part of the field value, and might or might not be
   significant depending on the input conversion rules for the field data type.
   For example, in:
<programlisting>
'(  42)'
</programlisting>
   the whitespace will be ignored if the field type is integer, but not if
   it is text.
  </para>

  <para>
   As shown previously, when writing a composite value you can write double
   quotes around any individual field value.
   You <emphasis>must</emphasis> do so if the field value would otherwise
   confuse the composite-value parser.  In particular, fields containing
   parentheses, commas, double quotes, or backslashes must be double-quoted.
   To put a double quote or backslash in a quoted composite field value,
   precede it with a backslash.  (Also, a pair of double quotes within a
   double-quoted field value is taken to represent a double quote character,
   analogously to the rules for single quotes in SQL literal strings.)
   Alternatively, you can avoid quoting and use backslash-escaping to
   protect all data characters
   that would otherwise be taken as composite syntax.
  </para>

  <para>
   A completely empty
Title: Composite Type Input and Output Syntax in PostgreSQL
Summary
This section explains the external text representation of composite values in PostgreSQL. It describes how composite values are formatted using parentheses and commas, and how whitespace is handled. The text emphasizes the importance of proper quoting for field values that might confuse the parser, particularly those containing special characters like parentheses, commas, double quotes, or backslashes. It also provides guidance on how to include double quotes or backslashes within quoted field values using escape characters. The section offers examples and details on the syntax rules for representing composite values in text form, ensuring accurate interpretation of complex data structures.