There are several ways to store XML data in Oracle Database.

Storage of XMLType tables and views is outlined in Figure 2-1.

If you have existing relational data, you can access it as XML data by creating XMLType views over it. You can use the following to define the XMLType views:

• SQL/XML functions. See Generation of XML Data from Relational Data and XQuery and Oracle XML DB.

• Object types: object tables, object constructors, and object views.

Regardless of which storage options you choose for your application, Oracle XML DB provides the same functionality. Though the storage model you use can affect your application performance and XML data fidelity, it is totally independent of how frequently you query or update your data and what APIs your application uses.

How structured your XML data is, and whether it is based on an XML schema, can influence how you store it.

If your XML data is not XML Schema-based, then, regardless of how structured it is, you can store it in an XMLType table or view as binary XML, or you can store it as a file in an Oracle XML DB Repository folder. You cannot store it object-relationally.

If your XML data is XML Schema-based then you must store it as binary XML or object-relationally.

You can program your Oracle XML DB applications in Java (JDBC, Java Servlets) or PL/SQL.

Oracle XML DB offers a full range of XML processing options.

The following are available and should be considered when designing your Oracle XML DB application:

• XML Generation and XMLType views. Whether you need to generate (or regenerate) XML data. See Generation of XML Data from Relational Data.

• Whether your application is data-centric or document-centric, or both. See Overview of How To Use Oracle XML DB.

• DOM fidelity, document fidelity. XMLType storage, whether object-relational or binary XML, preserves DOM fidelity. That is, A DOM created from an XML document stored as XMLType is identical to a DOM created from the original document. However, there could be differences in insignificant whitespace. See DOM Fidelity, SYS_XDBPD$ and DOM Fidelity for Object-Relational Storage, and PL/SQL APIs for XMLType.

  If you need to preserve document fidelity (insignificant whitespace) in addition to DOM fidelity, then store two copies of your original document: one as an XMLType instance for database use and XML processing, the other as a CLOB instance to provide document fidelity.

• XPath searching. You can use XPath syntax embedded in a SQL statement to query XML content in the database. See Query and Update of XML Data, Access to Oracle XML DB Repository Data, andRepository Access Using RESOURCE_VIEW and PATH_VIEW.

• How often XML documents are accessed, updated, and manipulated. See Query and Update of XML Data.

• Whether you need to update fragments or whole documents. You can use XPath expressions to specify individual elements and attributes of your document during updates, without rewriting the entire document. This is more efficient, especially for large XML documents. See Updating XML Data.

• Which kinds of indexing best suit your application and data. See Indexes for XMLType Data.

• XSLT. Whether you need to transform the XML data to HTML, WML, or other languages, and, if so, how your application does this. While storing XML documents in Oracle XML DB, you can optionally ensure that their structure complies with (validates against) specific XML schemas. See Transformation and Validation of XMLType Data.

Design considerations for applications that use Oracle XML DB Repository include access method, security needs, and whether you need versioning.

There are two main repository access methods:

• Navigation-based access or path-based access. This is suitable for both content/document and data oriented applications. Oracle XML DB provides the following languages and access APIs:

  • SQL access through resource and path views. See Repository Access Using RESOURCE_VIEW and PATH_VIEW.

  • PL/SQL access using package DBMS_XDB or packages DBMS_XDB_ADMIN, DBMS_XDB_CONFIG and DBMS_XDB_REPOS. See PL/SQL Access to Oracle XML DB Repository.

  • Protocol-based access using HTTP(S)/WebDAV or FTP, most suited to content-oriented applications. See Repository Access Using Protocols.

• Query-based access. This can be most suited to data oriented applications. Oracle XML DB provides access using SQL queries through the following APIs:

  • Java access (through JDBC). See Java DOM API for XMLType.

  • PL/SQL access. See PL/SQL APIs for XMLType.

These options for accessing repository data are also discussed in Access to Oracle XML DB Repository Data.

You can also consider the following access criteria:

• What levels of security you need. See Repository Access Control.

• Whether you need to version the data. See Resource Versions.

Oracle XML DB is an integrated part of Oracle Database, and works well with other database options and features.

• Oracle Database Advanced Queuing (AQ) – merge XML payloads. See XML Data Exchange Using Oracle Database Advanced Queuing and Oracle Database Advanced Queuing User's Guide

• Oracle GoldenGate and Oracle Active Data Guard – replicate and safeguard XML data, or perform a rolling upgrade. See Oracle GoldenGate and Oracle Data Guard Concepts and Administration

• Oracle Exadata Storage Server Software – high-performance, scalable, and highly available use of XML data. See Oracle Exadata Storage Server Software User's Guide.

• Oracle Real Application Clusters (Oracle RAC) – Use XML data with clusters of database instances. See Oracle Real Application Clusters Administration and Deployment Guide

• Oracle Multitenant option – Use XML data with a multitenant architecture, where each pluggable database has its own Oracle XML DB Repository. See Oracle Multitenant Administrator's Guide

• Compression and Encryption – You can compress or encrypt binary XML data that uses SecureFiles LOB storage. For XML data stored object-relationally, you can compress or encrypt XML elements and attributes individually.

• Parallel Execution – Execution of the following operations can be carried out in parallel:

  • A query of XMLType data

  • DML for XMLType data stored as binary XML using SecureFiles LOBs

  • A direct load for an XMLType table on which an Oracle Text CONTEXT index is defined

  See Also:

  Oracle Database Concepts