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<section id="JCR.MultilanguageSupport">
  <title>Multi-language support in eXo JCR RDB backend</title>


    <para>Whenever relational database is used to store multilingual text data
    of eXo Java Content Repository, it is necessary to adapt configuration in order to
    support UTF-8 encoding. Here is a short HOWTO instruction for several
    supported RDBMS with examples.</para>

    <para>The configuration file you have to modify:
    .../webapps/portal/WEB-INF/conf/jcr/repository-configuration.xml</para>

    <note>
      <para>Datasource <parameter>jdbcjcr</parameter> used in examples can be
      configured via <classname>InitialContextInitializer</classname>
      component.</para>
    </note>

  <section id="JCR.MultilanguageSupport.Oracle">
    <title>Oracle</title>

    <para>In order to run multilanguage JCR on an Oracle backend Unicode
    encoding for characters set should be applied to the database. Other
    Oracle globalization parameters don't make any impact. The only property
    to modify is <constant>NLS_CHARACTERSET</constant>.</para>

    <para>We have tested <constant>NLS_CHARACTERSET</constant> =
    <constant>AL32UTF8</constant> and it works well for many European and
    Asian languages.</para>

    <para>Example of database configuration (used for JCR
    testing):<programlisting>NLS_LANGUAGE             AMERICAN
NLS_TERRITORY            AMERICA
NLS_CURRENCY             $
NLS_ISO_CURRENCY         AMERICA
NLS_NUMERIC_CHARACTERS   .,
NLS_CHARACTERSET         AL32UTF8
NLS_CALENDAR             GREGORIAN
NLS_DATE_FORMAT          DD-MON-RR
NLS_DATE_LANGUAGE        AMERICAN
NLS_SORT                 BINARY
NLS_TIME_FORMAT          HH.MI.SSXFF AM
NLS_TIMESTAMP_FORMAT     DD-MON-RR HH.MI.SSXFF AM
NLS_TIME_TZ_FORMAT       HH.MI.SSXFF AM TZR
NLS_TIMESTAMP_TZ_FORMAT  DD-MON-RR HH.MI.SSXFF AM TZR
NLS_DUAL_CURRENCY        $
NLS_COMP                 BINARY
NLS_LENGTH_SEMANTICS     BYTE
NLS_NCHAR_CONV_EXCP      FALSE
NLS_NCHAR_CHARACTERSET   AL16UTF16</programlisting></para>

    <warning>
      <para>JCR doesn't use NVARCHAR columns, so that the value of the
      parameter NLS_NCHAR_CHARACTERSET does not matter for JCR.</para>
    </warning>

    <para>Create database with Unicode encoding and use Oracle dialect for the
    Workspace Container:</para>

    <programlisting language="xml">&lt;workspace name="collaboration"&gt;
          &lt;container class="org.exoplatform.services.jcr.impl.storage.jdbc.optimisation.CQJDBCWorkspaceDataContainer"&gt;
            &lt;properties&gt;
              &lt;property name="source-name" value="jdbcjcr" /&gt;
              &lt;property name="dialect" value="oracle" /&gt;
              &lt;property name="multi-db" value="false" /&gt;
              &lt;property name="max-buffer-size" value="200k" /&gt;
              &lt;property name="swap-directory" value="target/temp/swap/ws" /&gt;
            &lt;/properties&gt;
          .....</programlisting>
  </section>

  <section id="JCR.MultilanguageSupport.DB2">
    <title>DB2</title>

    <para>DB2 Universal Database (DB2 UDB) supports <ulink
    url="http://publib.boulder.ibm.com/infocenter/db2luw/v9/index.jsp?topic=/com.ibm.db2.udb.admin.doc/doc/c0004821.htm">UTF-8
    and UTF-16/UCS-2</ulink>. When a Unicode database is created, CHAR,
    VARCHAR, LONG VARCHAR data are stored in UTF-8 form. It's enough for JCR
    multi-lingual support.</para>

    <para>Example of UTF-8 database creation:<programlisting>DB2 CREATE DATABASE dbname USING CODESET UTF-8 TERRITORY US</programlisting></para>

    <para>Create database with UTF-8 encoding and use db2 dialect for
    Workspace Container on DB2 v.9 and higher:</para>
    
    <programlisting language="xml">&lt;workspace name="collaboration"&gt;
          &lt;container class="org.exoplatform.services.jcr.impl.storage.jdbc.optimisation.CQJDBCWorkspaceDataContainer"&gt;
            &lt;properties&gt;
              &lt;property name="source-name" value="jdbcjcr" /&gt;
              &lt;property name="dialect" value="db2" /&gt;
              &lt;property name="multi-db" value="false" /&gt;
              &lt;property name="max-buffer-size" value="200k" /&gt;
              &lt;property name="swap-directory" value="target/temp/swap/ws" /&gt;
            &lt;/properties&gt;
          .....</programlisting>

    <note>
      <para>For DB2 v.8.x support change the property "dialect" to
      db2v8.</para>
    </note>
  </section>

  <section id="JCR.MultilanguageSupport.MySQL">
    <title>MySQL</title>

    <para>JCR MySQL-backend requires special dialect <ulink
    url="http://dev.mysql.com/doc/refman/5.0/en/charset-unicode-utf8.html">MySQL-UTF8</ulink>
    to be used for internationalization support. But the database default
    charset should be latin1 to use limited index space effectively (1000
    bytes for MyISAM engine, 767 for InnoDB). If database default charset is
    multibyte, a JCR database initialization error is thrown concerning index
    creation failure. In other words, JCR can work on any singlebyte default
    charset of database, with UTF8 supported by MySQL server. But we have
    tested it only on latin1 database default charset.</para>

    <para>Repository configuration, workspace container entry
    example:</para>
    
    <programlisting language="xml">&lt;workspace name="collaboration"&gt;
          &lt;container class="org.exoplatform.services.jcr.impl.storage.jdbc.optimisation.CQJDBCWorkspaceDataContainer"&gt;
            &lt;properties&gt;
              &lt;property name="source-name" value="jdbcjcr" /&gt;
              &lt;property name="dialect" value="mysql-utf8" /&gt;
              &lt;property name="multi-db" value="false" /&gt;
              &lt;property name="max-buffer-size" value="200k" /&gt;
              &lt;property name="swap-directory" value="target/temp/swap/ws" /&gt;
            &lt;/properties&gt;
          .....</programlisting>
  </section>

  <section id="JCR.MultilanguageSupport.PostgreSQL">
    <title>PostgreSQL</title>

    <para>On PostgreSQL-backend, multilingual support can be enabled in <ulink
    url="http://www.postgresql.org/docs/8.3/interactive/charset.html">different
    ways</ulink>:<itemizedlist>
        <listitem>
          <para>Using the locale features of the operating system to provide
          locale-specific collation order, number formatting, translated
          messages, and other aspects. UTF-8 is widely used on Linux
          distributions by default, so it can be useful in such case.</para>
        </listitem>

        <listitem>
          <para>Providing a number of different character sets defined in the
          PostgreSQL server, including multiple-byte character sets, to
          support storing text of any languages, and providing character set
          translation between client and server. We recommend to use UTF-8
          database charset, it will allow any-to-any conversations and make
          this issue transparent for the JCR.</para>
        </listitem>
      </itemizedlist></para>

    <para>Create database with UTF-8 encoding and use PgSQL dialect for
    Workspace Container:</para>
    
    <programlisting language="java">&lt;workspace name="collaboration"&gt;
          &lt;container class="org.exoplatform.services.jcr.impl.storage.jdbc.optimisation.CQJDBCWorkspaceDataContainer"&gt;
            &lt;properties&gt;
              &lt;property name="source-name" value="jdbcjcr" /&gt;
              &lt;property name="dialect" value="pgsql" /&gt;
              &lt;property name="multi-db" value="false" /&gt;
              &lt;property name="max-buffer-size" value="200k" /&gt;
              &lt;property name="swap-directory" value="target/temp/swap/ws" /&gt;
            &lt;/properties&gt;
          .....</programlisting>
  </section>
</section>
