Saturday, November 13, 2010

Saving large XMLTypes in Oracle databases

If you try to save a large XMLType that is over 4k characters long, you'll get this error:

can bind a LONG value only for insert into a LONG column

Oracle database has troubles binding large strings. One solution is to use a temporary clob to store the XML data, and bind that to the SQL-statement.

Connection con = ...
String xml = "<test>test</test>";
oracle.sql.CLOB clob = null;

clob = CLOB.createTemporary(con, true,
clob.setString(1, xml);

PrepareStatement s = con.prepareStatement(
"INSERT INTO table (xml) VALUES(XMLType(?))"

s.setObject(1, clob);

Using this method, you can store large XML-documents as XMLType in the Oracle database. But there is still a limitation with the XMLType. The XMLType cannot store any text-nodes and attributes values larger than 64k. Oracle suggests to use a XMLType CLOB-storage column to store really large XML-documents. But then, we cannot use native XML-parsing functions, which defeats the purpose of the XMLType column...

In newer versions of Oracle XML DB, this limit has been lifted.


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