Oracle PL/SQL Programming, 5th Edition

Predefined Object Types

Starting with Oracle9i Database Release 1, Oracle provides a collection of useful, predefined object types:

XMLType

Use this to store and manipulate XML data.

URI types

Use these to store uniform resource identifiers (such as HTML addresses).

Any types

Use these to define a PL/SQL variable that can hold any type of data.

The following subsections discuss these predefined object types in more detail.

The XMLType Type

Oracle9i Database introduced a native object type called XMLType. You can use XMLType to define database columns and PL/SQL variables containing XML documents. Methods defined on XMLType enable you to instantiate new XMLType values, to extract portions of an XML document, and to otherwise manipulate the contents of an XML document in various ways.

XML is a huge subject that I can’t hope to cover in detail in this book. However, if you’re working with XML from PL/SQL, there are at least two things you need to know about:

XMLType

A built-in object type that enables you to store XML documents in a database column or in a PL/SQL variable. XMLType was introduced in Oracle9i Database Release 1.

XQuery

A query language used for retrieving and constructing XML documents. XQuery was introduced in Oracle Database 10g Release 2.

Starting with these two technologies and exploring further, you’ll encounter many other XML related topics that will likely prove useful: XPath for referring to portions of an XML document, XML Schema for describing document structure, and so forth. ...