Overview

This section provides a brief overview to the supported data types, short tag and XSD schema, advantages and disadvantages of indices and need for views.

Supported Types

The XMLRECORD column must be of XML data type, which ensures that the files created with the NOXMLSCHEMA=YES qualifier are not supported by CREATE-VIEW/CREATE-EXTINDEX. If you try to create and index on a non-XML type (BLOB) you will get the following error message.

Non-xmltype column not supported

Short Tag and XSD Schema

The difference between creating views and indices on short tag or XSD schema based XML is minimal. The following table shows examples for the same.

Format	Example
Short Tag	For example <row><c1>TEMENOS</c1></row>)
XSD schema based XML	For example <row><Mnemonic>TEMENOS</ Mnemonic ></row>).

The only difference is the resulting SQL command. The views are not used by the Temenos Transact query interface, which takes performance out of concern. The key difference for the view or index interface lies in the component used to determine the attribute, type and XML tag representation for each field. The following table shows the component

File Format	Component Used
XSD Schema	Cross-reference map
Non-schema	Dictionary

This cross-reference map is generated from Standard Selection and is keyed by the schema name (CUSTOMER) followed by @XMLREF. Refer Appendix A for an example of an XMLREF.

In Oracle (XMLORACLE type), schema based XML does not get impacted from queries without indexes as much as the short tag XML as the storage of the XML document is CLOB (similar to BLOB) for short tag.

For schema based XML and DB2/SQL Servers, the SQL engine can navigate directly to the element value.

Advantages and Disadvantages of Indices

This section provides the justification why indices are required and possible negative impact of indices.

Need for Views

With the Release 3 generation of drivers, the translation of jQL queries to SQL does not make use of views on RDBMS. However, views can be used outside Temenos Transact applications by customers who are used to using SQL as a method of gathering information. For example, the customers may wish to use a utility like Crystal Reports. Within Windows, any ODBC compliant product can view the XML data as a relational model.