Updating xml in sql

10 Sep

These objects can be implemented in a relational format through tables with referential constraints optionally implemented between the tables.They can also be implemented by using an XMLSchema to decompose an XMLType document into a set of objects.Index usage with b-tree and function-based indexes is enhanced, and in-place updates can be performed on pieces of the document using XPath rewrite.All of this helps performance and is discussed in more detail later in this article.The SQL/XML standard has been under development to provide a mechanism that allows us to generate XML from a relational query and, conversely, provide the ability to deliver SQL data from XML documents.Oracle XML DB in Oracle Database 10 Release 2 implements SQL 2003 and features from the upcoming SQL/XML standard release.

The document is not stored as a byte-for-byte representation of the original, and the order of data in a document is not maintained. Think of highly structured data as being mostly XML, where each element of the data can be clearly defined. XML can be stored in Oracle in an unstructured manner using CLOB storage such that SQL queries will not know the structure of the data.If you are a DBA or a developer new to the implementation of XML in Oracle, this article is for you: you will get an overview of SQL and XML interoperability and learn how to begin working with XML documents stored in an Oracle 10 Release 2 that DBAs and developers should become comfortable with before beginning to work with XML in the database.Thanks to these SQL/XML features, the skills you've already acquired while working with relational data can easily be enhanced to help you work with XML.The implementation of these standards in Oracle allows us to look inside an XML document in ways that were not possible in older SQL standards. A new datatype, XMLType, was introduced in Oracle9 Database Release 1 to allow an XML document in the database to be accessible in SQL and at the same time allow XML developers the ability to use XML standards on a document.This datatype tells the database that the content is in XML format and allows us to perform queries on an XML document.XMLType can be used to create a table, column, or view.It can also be used as a datatype for parameters and variables.Using XMLType rather than a relational or CLOB implementation provides a layer of separation between the application and storage model.This separation can allow data to move to a different storage model without being tied to a CLOB or relational model.One specific example of this is an XMLType table, which can be implemented using either of the two storage models.An XMLType table is unstructured when implemented as a LOB by using the “XMLType store as CLOB” syntax shown below: Let’s focus on the structured and unstructured storage for XML data and look at these in more detail. Structured XML storage is implemented as a set of objects.