Release 10.1A: OpenEdge Development:
Programming Interfaces

Introduction

The XML features of temp-tables and ProDataSets allow you to take advantage of their rich relational features while providing a standards-based method for sharing data and schema with remote clients. These XML features include the following:

Read XML data, XML Schema, or both to populate an empty temp-table or ProDataSet. For ProDataSets, the XML document can also contain before-image information.
Read XML data, XML Schema, or both into temp-tables and ProdataSets that already contain data and schema.
Write XML data, XML Schema, or both from a temp-table or ProDataSet to XML documents. XML Schema is written using the XML Schema Definition language (XSD). If ProDataSet temp-table buffers have before-image information, that information can also be written.
Perform round-trip XML write/reads. 4GL temp-table and ProDataSets are feature-rich and their definitions cannot be completely represented by basic XSD. The 4GL adds Progress-specific attributes to the XML Schema it writes so that temp-tables and ProDataSets can be fully restored when the XML Schemas are read back into Progress.

The XML features are available as attributes and methods on:

Temp-table objects
Temp-table buffer objects (each buffer instance of a particular temp-table can have different XML properties)
ProDataSet objects

During an XML read, only the XML elements and attributes relevant to Progress temp-tables and ProDataSets are used. If the source XML contains extra information and you were to subsequently write the XML document from the 4GL, it could differ from the original XML in the following ways:

Original formatting (white space, line indents, line breaks) are not preserved.
Elements or attributes that are not relevant for the 4GL are not preserved.
Note: If preserving the original XML data is important to your application, you may want to use the 4GL DOM or SAX interfaces for more control over your read and write operations.