XML data movement
Support for XML data movement is provided by the load, import and export utilities. Support for moving tables that contain XML columns without taking the tables offline is provided by the ADMIN_MOVE_TABLE stored procedure.
Importing XML data
The import utility can be used to insert XML documents into a regular relational table. Only well-formed XML documents can be imported.
Use the XML FROM
option of the IMPORT command to specify the location of the XML documents
to import. The XMLVALIDATE option specifies how imported documents
should be validated. You can select to have the imported XML data
validated against a schema specified with the IMPORT command, against
a schema identified by a schema location hint inside of the source
XML document, or by the schema identified by the XML Data Specifier
in the main data file. You can also use the XMLPARSE option to specify
how whitespace is handled when the XML document is imported. The xmlchar
and xmlgraphic
file
type modifiers allow you to specify the encoding characteristics for
the imported XML data.
Loading XML data
The load utility offers an efficient way to insert large volumes of XML data into a table. This utility also allows certain options unavailable with the import utility, such as the ability to load from a user-defined cursor.
Like
the IMPORT command, with the LOAD command you can specify the location
of the XML data to load, validation options for the XML data, and
how whitespace is handled. As with IMPORT, you can use the xmlchar
and xmlgraphic
file
type modifiers to specify the encoding characteristics for the loaded
XML data.
Exporting XML data
Data may be exported from tables that include one or more columns with an XML data type. Exported XML data is stored in files separate from the main data file containing the exported relational data. Information about each exported XML document is represented in the main exported data file by an XML data specifier (XDS). The XDS is a string that specifies the name of the system file in which the XML document is stored, the exact location and length of the XML document inside of this file, and the XML schema used to validate the XML document.
You can use the
XMLFILE, XML TO, and XMLSAVESCHEMA parameters of the EXPORT command
to specify details about how exported XML documents are stored. The xmlinsepfiles
, xmlnodeclaration
, xmlchar
,
and xmlgraphic
file type modifiers allow you to specify
further details about the storage location and the encoding of the
exported XML data.
Moving tables online
The ADMIN_MOVE_TABLE stored procedure moves the data in an active table into a new table object with the same name, while the data remains online and available for access. The table can include one or more columns with an XML data type. Use an online table move instead of an offline table move if you value availability more than cost, space, move performance, and transaction overhead
You can call the procedure once or multiple times, one call for each operation performed by the procedure. Using multiple calls provides you with additional options, such as cancelling the move or controlling when the target table is taken offline to be updated.