In SQLJ applications, you can store data in XML columns
and retrieve data from XML columns.
In DB2® tables, the XML built-in
data type is used to store XML data in a column as a structured set
of nodes in a tree format.
SQLJ applications can send XML data to the data server or retrieve
XML data from the data server in one of the following forms:
- As textual XML data
- As binary XML data (data that is in the Extensible Dynamic Binary XML DB2 Client/Server Binary XML Format),
if the data server supports it
In SQLJ applications, you can:
- Store an entire XML document in an XML column using INSERT, UPDATE,
or MERGE statements.
- Retrieve an entire XML document from an XML column using single-row
SELECT statements or iterators.
- Retrieve a sequence from a document in an XML column by using
the SQL XMLQUERY function to retrieve the sequence in the database,
and then using single-row SELECT statements or iterators to retrieve
the serialized XML string data into an application variable.
- Retrieve a sequence from a document in an XML column by using
an XQuery expression, prepended with the string 'XQUERY', to retrieve
the elements of the sequence into a result table in the database,
in which each row of the result table represents an item in the sequence.
Then use using single-row SELECT statements or iterators to retrieve
the data into application variables.
- Retrieve a sequence from a document in an XML column as a user-defined
table by using the SQL XMLTABLE function to define the result table
and retrieve it. Then use using single-row SELECT statements or iterators
to retrieve the data from the result table into application variables.
- You can update or retrieve XML data as textual XML
data. Alternatively, for connections to a data server that supports
binary XML data, you can update or retrieve XML data as binary XML
data.
For data retrieval, you use the Datasource or Connection property
xmlFormat to control whether the format of the retrieved data is textual
XML or binary XML.
For update of data in XML columns, xmlFormat
has no effect. If the input data is binary XML data, and the data
server does not support binary XML data, the input data is converted
to textual XML data. Otherwise, no conversion occurs.
The format
of XML data is transparent to the application. Storage and retrieval
of binary XML data on a DB2 for z/OS® data
server requires version 4.9 or later of the IBM® Data Server
Driver for JDBC and SQLJ.
Storage and retrieval of binary XML data on a DB2 for Linux, UNIX, and Windows data
server requires version 4.11 or later of the IBM Data Server
Driver for JDBC and SQLJ.
JDBC 4.0 java.sql.SQLXML objects can be used to
retrieve and update data in XML columns. Invocations of metadata methods,
such as ResultSetMetaData.getColumnType return
the integer value java.sql.Types.SQLXML for an XML
column type.
DB2 Version 10.1 for Linux, UNIX, and Windows