This appendix describes the restrictions associated with Oracle XML DB.
Thin JDBC Driver Not Supported by Some XMLType Functions – Methods
existsNode() work with the thick JDBC driver only. Not all
oracle.xdb.XMLType functions are supported by the thin JDBC driver. If you do not use
oracle.xdb.XMLType classes and the OCI driver, you could lose performance benefits.
Mapping XML elements or attributes to these data types using the
SQLType annotation in an XML schema
Generating XML data from these data types using SQL functions
Within SQL functions
XMLTable, using SQL function
ora:view on tables that contain columns with these data types
To handle, store, or generate XML data that contains multibyte characters, Oracle strongly recommends that you use AL32UTF8 as the database character set.
XML Identifier Length Limit – Oracle XML DB supports only XML identifiers that are 4000 characters long, or shorter.
Repository File Size Limit – The maximum size of a file in Oracle XML DB Repository is 4 gigabytes. This implies the following limits for different kinds of file data:
4 gigabytes for any LOB, which means 2 gigacharacters for a
CLOB stored in the database character set AL32UTF8.
4 gigabytes for binary XML encoded data, which can mean from 20 to 40 gigabytes of external XML data before encoding.
Indeterminate for XML data stored object-relationally.
See Also:"Oracle XML DB Support for XQuery" for information about Oracle XML DB support for XQuery