varying(5)</computeroutput>
INSERT INTO test2 VALUES ('too long'::varchar(5)); -- explicit truncation
SELECT b, char_length(b) FROM test2;
<computeroutput>
   b   | char_length
-------+-------------
 ok    |           2
 good  |           5
 too l |           5
</computeroutput>
</programlisting>
    <calloutlist>
     <callout arearefs="co.datatype-char">
      <para>
       The <function>char_length</function> function is discussed in
       <xref linkend="functions-string"/>.
      </para>
     </callout>
    </calloutlist>
   </example>

   <para>
    There are two other fixed-length character types in
    <productname>PostgreSQL</productname>, shown in <xref
    linkend="datatype-character-special-table"/>.
    These are not intended for general-purpose use, only for use
    in the internal system catalogs.
    The <type>name</type> type is used to store identifiers. Its
    length is currently defined as 64 bytes (63 usable characters plus
    terminator) but should be referenced using the constant
    <symbol>NAMEDATALEN</symbol> in <literal>C</literal> source code.
    The length is set at compile time (and
    is therefore adjustable for special uses); the default maximum
    length might change in a future release. The type <type>"char"</type>
    (note the quotes) is different from <type>char(1)</type> in that it
    only uses one byte of storage, and therefore can store only a single
    ASCII character. It is used in the system
    catalogs as a simplistic enumeration type.
   </para>

    <table id="datatype-character-special-table">
     <title>Special Character Types</title>
     <tgroup cols="3">
      <thead>
       <row>
        <entry>Name</entry>
        <entry>Storage Size</entry>
        <entry>Description</entry>
       </row>
      </thead>
      <tbody>
       <row>
        <entry><type>"char"</type></entry>
        <entry>1 byte</entry>
        <entry>single-byte internal type</entry>
       </row>
       <row>
        <entry><type>name</type></entry>
        <entry>64 bytes</entry>
        <entry>internal type for object names</entry>
       </row>
      </tbody>
     </tgroup>
    </table>

  </sect1>

 <sect1 id="datatype-binary">
  <title>Binary Data Types</title>

  <indexterm zone="datatype-binary">
   <primary>binary data</primary>
  </indexterm>

  <indexterm zone="datatype-binary">
   <primary>bytea</primary>
  </indexterm>

   <para>
    The <type>bytea</type> data type allows storage of binary strings;
    see <xref linkend="datatype-binary-table"/>.
   </para>

   <table id="datatype-binary-table">
    <title>Binary Data Types</title>
    <tgroup cols="3">
     <colspec colname="col1" colwidth="1*"/>
     <colspec colname="col2" colwidth="3*"/>
     <colspec colname="col3" colwidth="2*"/>
     <thead>
      <row>
       <entry>Name</entry>
       <entry>Storage Size</entry>
       <entry>Description</entry>
      </row>
     </thead>
     <tbody>
      <row>
       <entry><type>bytea</type></entry>
       <entry>1 or 4 bytes plus the actual binary string</entry>
       <entry>variable-length binary string</entry>
      </row>
     </tbody>
    </tgroup>
   </table>

   <para>
    A binary string is a sequence of octets (or bytes).  Binary
    strings are distinguished from character strings in two
    ways.  First, binary strings specifically allow storing
    octets of value zero and other <quote>non-printable</quote>
    octets (usually, octets outside the decimal range 32 to 126).
    Character strings disallow zero octets, and also disallow any
    other octet values and sequences of octet values that are invalid
    according to the database's selected character set encoding.
    Second, operations on binary strings process the actual bytes,
    whereas the processing of character strings depends on locale settings.
    In short, binary strings are appropriate for storing data that the
    programmer thinks of as <quote>raw bytes</quote>, whereas character
    strings are appropriate