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     <h2 class="title">
      <a name="charset-restrictions">
      </a>
      12.11 Restrictions on Character Sets
     </h2>
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    <li class="listitem">
     <p>
      Identifiers are stored in
      <code class="literal">
       mysql
      </code>
      database
          tables (
      <code class="literal">
       user
      </code>
      ,
      <code class="literal">
       db
      </code>
      , and so
          forth) using
      <code class="literal">
       utf8mb3
      </code>
      , but identifiers can
          contain only characters in the Basic Multilingual Plane (BMP).
          Supplementary characters are not permitted in identifiers.
     </p>
    </li>
    <li class="listitem">
     <p>
      The
      <code class="literal">
       ucs2
      </code>
      ,
      <code class="literal">
       utf16
      </code>
      ,
      <code class="literal">
       utf16le
      </code>
      , and
      <code class="literal">
       utf32
      </code>
      character sets have the following restrictions:
     </p>
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       <li class="listitem">
        <p>
         None of them can be used as the client character set. See
         <a class="xref" href="charset-connection.html#charset-connection-impermissible-client-charset" title="Impermissible Client Character Sets">
          Impermissible Client Character Sets
         </a>
         .
        </p>
       </li>
       <li class="listitem">
        <p>
         It is currently not possible to use
         <a class="link" href="load-data.html" title="15.2.9 LOAD DATA Statement">
          <code class="literal">
           LOAD DATA
          </code>
         </a>
         to load data
              files that use these character sets.
        </p>
       </li>
       <li class="listitem">
        <p>
         <code class="literal">
          FULLTEXT
         </code>
         indexes cannot be created on a
              column that uses any of these character sets. However, you
              can perform
         <code class="literal">
          IN BOOLEAN MODE
         </code>
         searches on
              the column without an index.
        </p>
       </li>
      </ul>
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    </li>
    <li class="listitem">
     <p>
      The
      <a class="link" href="regexp.html#operator_regexp">
       <code class="literal">
        REGEXP
       </code>
      </a>
      and
      <a class="link" href="regexp.html#operator_regexp">
       <code class="literal">
        RLIKE
       </code>
      </a>
      operators work in byte-wise fashion, so they are not multibyte
          safe and may produce unexpected results with multibyte
          character sets. In addition, these operators compare
          characters by their byte values and accented characters may
          not compare as equal even if a given collation treats them as
          equal.
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