XML data type

The XML data type is used to define columns of a table that store XML values. This pureXML® data type provides the ability to store well-formed XML documents in a database.

All XML data is stored in the database in an internal representation. Character data in this internal representation is in the UTF-8 encoding scheme.

XML values that are stored in an XML column have an internal representation that is not a string and not directly comparable to string values. An XML value can be transformed into a serialized string value that represents the XML document by using the XMLSERIALIZE function or by retrieving the value into an application variable of an XML, string, or binary type. Similarly, a string value that represents an XML document can be transformed to an XML value by using the XMLPARSE function or by storing a value from a string, binary, or XML application data type in an XML column.

The size of an XML value in a DB2® table has no architectural limit. However, serialized XML data that is stored in or retrieved from an XML column is limited to 2 GB.

Validation of an XML document against an XML schema, typically performed during INSERT or UPDATE into an XML column, is supported by the XML schema repository (XSR). If an XML column has an XML type modifier, documents that are inserted into the column or updated in the column are automatically validated against an XML schema.