NAME

        AnyData::Format::XML - tiedhash and DBI access to XML

SYNOPSIS

        # access XML data via a multidimensional tied hash
        # see AnyData.pod for full details
        #
        use AnyData;
        my $table = adTie( 'XML', $file, $mode, $flags );

        OR

        # convert data to and from XML
        # see AnyData.pod for full details
        #
        use AnyData;
        adConvert( 'XML', $file1, $any_other_format, $file2, $flags );
        adConvert( $any_other_format, $file1, 'XML', $file2, $flags );

        OR

        # access the data via DBI and SQL
        # see DBD::AnyData.pod for full details
        #
        use DBI;
        my $dbh = DBI->connect( 'dbi:AnyData' );
        $dbh->func('mytable','XML',$file,$flags,'ad_catalog');

       See below for a description of the optional flags that apply to all of these examples.

DESCRIPTION

       This module allows you to create, search, modify and/or convert XML data and files by
       treating them as databases without having to actually create separate database files.  The
       data can be accessed via a multidimensional tiedhash using AnyData.pm or via DBI and SQL
       commands using DBD::AnyData.pm.  See those modules for complete details of usage.

       The module is built on top of Michel Rodriguez's excellent XML::Twig which means that the
       AnyData interfaces can now include information from DTDs, be smarter about inferring data
       structure, reduce memory consumption on huge files, and provide access to many powerful
       features of XML::Twig and XML::Parser on which it is based.

       Importing options allow you to import/access/modify XML of almost any length or
       complexity.  This includes the ability to access different subtrees as separate or joined
       databases.

       Exporting and converting options allow you to take data from almost any source (a perl
       array, any DBI database, etc.) and output it as an XML file.  You can control the
       formatting of the resulting XML either by supplying a DTD listing things like nesting of
       tags and which columns should be output as attributes and/or you can use XML::Twig
       pretty_print settings to generate half a dozen different levels of compactness or
       whitespace in how the XML looks.

       The documentation below outlines the special flags that can be used in either of the
       interfaces to fine-tune how the XML is treated.

       The flags listed below define the relationship between tags and attributes in the XML
       document and columns in the resulting database.  In many cases, you can simply accept the
       defaults and the database will be built automatically.  However, you can also fine tune
       the generation of the database by specifying which tags and attributes you are interested
       in and their relationship with database columns.

USAGE

   Prerequisites
       To use the tied hash interface, you will need

        AnyData
        XML::Twig
        XML::Parser

       To use the DBI/SQL interface, you will need those, and also

        DBI
        DBD::AnyData

   Required flags ( none )
       If no flags are specified, then the module determines the database structure from
       examining the file or data itself, making use of the DTD if there is one, otherwise
       scanning the first child of the XML tree for structural information.

   Optional flags
        If the default behavior is not sufficient, you may either specify a
        "record_tag" which will be used to define column names, or you can define an
        entire tag-to-column mapping.

       For simple XML, no flags are necessary:

        <table>
           <row row_id="1"><name>Joe</name><location>Seattle</location></row>
           <row row_id="2"><name>Sue</name><location>Portland</location></row>
        </table>

       The record_tag will default to the first child, namely "row".  The column names will be
       generated from the attributes of the record tag and all of the tags included under the
       record tag, so the column names in this example will be "row_id","name","location".

       If the record_tag is not the first child, you will need to specify it.  For example:

        <db>
          <table table_id="1">
            <row row_id="1"><name>Joe</name><location>Seattle</location></row>
            <row row_id="2"><name>Sue</name><location>Portland</location></row>
          </table>
          <table table_id="2">
            <row row_id="1"><name>Bob</name><location>Boise</location></row>
            <row row_id="2"><name>Bev</name><location>Billings</location></row>
          </table>
        </db>

       In this case you will need to specify "row" as the record_tag since it is not the first
       child of the tree.  The column names will be generated from the attributes of row's parent
       (if the parent is not the root), from row's attributes and sub tags, i.e.
       "table_id","row_id","name","location".

       In some cases you will need to specify an entire tag-to-column mapping.  For example, if
       you want to use a different name for the database column than is used in the XML
       (especially if the XML tag is not a valid SQL column name).  You'd also need to specify a
       mapping if there are two tags with the same name in different places in the XML tree.

       The column mapping is a reference to an array of column definitions.  A column definition
       is either a simple name of a tag, or a hash reference with the key containing the full
       path of the XML tag and the value containing the desired column name alias.

       For example:

         col_map => [ 'part_id', 'part_name', 'availability' ];

       That will find the first three tags with those names and create the database using the
       same names for the tags.

       Or:

         col_map => [
                      { '/parts/shop/id'        => 'shop_id'},
                      { '/parts/shop/part/id'   => 'part_id'},
                      { '/parts/shop/part/name' => 'part_name'},
                    ];

       That would find the three tags referenced on the left and create a database with the three
       column names referenced on the right.

       When exporting XML, you can specify a DTD to control the output.  For example, if you
       import a table from CSV or from an Array, you can output as XML and specify which of the
       columns become tags and which become attributes and also specify the nesting of the tags
       in your DTD.

       The XML format parser is built on top of Michel Rodriguez's excellent XML::Twig which is
       itself based on XML::Parser.  Parameters to either of those modules may be passed in the
       flags for adTie() and the other commands including the "prettyPrint" flag to specify how
       the output XML is displayed and things like ProtocolEncoding.  ProtocolEncoding defaults
       to 'ISO-8859-1', all other flags keep the defaults of XML::Twig and XML::Parser.  See the
       documentation of those modules for details;

        CAUTION: Unlike other formats, the XML format does not save changes to
        the file as they are entered, but only saves the changes when you explicitly
        request them to be saved with the adExport() command.

AUTHOR & COPYRIGHT

       copyright 2000, Jeff Zucker <jeff@vpservices.com> all rights reserved