PL/SQL DBMS_XMLGEN.SETROWSETTAG

The DBMS_XMLGEN package in Oracle PL/SQL is a powerful tool for generating XML data from SQL queries. One of its features, the SETROWSETTAG procedure, allows you to customize the XML output by specifying the tag name for the rowset element. This is particularly useful when you need to transform the result of a SQL query into XML format and want more control over the structure and naming conventions of the generated XML document.

Overview

The SETROWSETTAG procedure is part of the DBMS_XMLGEN package, which provides several procedures and functions to generate XML data from SQL queries. By default, when you generate XML using DBMS_XMLGEN, the rowset is encapsulated within the tag. However, you can use SETROWSETTAG to change this default tag to a custom name that fits your application or XML data schema requirements.

Syntax

The syntax for the SETROWSETTAG procedure is straightforward:

DBMS_XMLGEN.SETROWSETTAG (
   ctx_handle  IN NUMBER,
   rowset_tag  IN VARCHAR2);

ctx_handle: This is the context handle returned by the DBMS_XMLGEN.NEWCONTEXT function, which initiates the XML generation process. It uniquely identifies the session of XML generation.
rowset_tag: This parameter allows you to specify the custom tag name for the rowset element. It replaces the default tag with the name you provide here.

Example

Here’s a step-by-step example of how to use DBMS_XMLGEN.SETROWSETTAG:

Create a Context: First, you need to create a context for XML generation using the DBMS_XMLGEN.NEWCONTEXT function.

DECLARE
  ctx_handle NUMBER;
BEGIN
  ctx_handle := DBMS_XMLGEN.NEWCONTEXT('SELECT * FROM employees'); -- Example query

Set Custom Rowset Tag: Next, use SETROWSETTAG to specify your custom rowset tag.

  DBMS_XMLGEN.SETROWSETTAG(ctx_handle, 'Employees');

Generate XML: After setting the custom rowset tag, you can proceed to generate XML from your SQL query.

  -- Generate XML
  DBMS_XMLGEN.GETXML(ctx_handle);

Close the Context: Finally, remember to close the context to free up resources.

  DBMS_XMLGEN.CLOSECONTEXT(ctx_handle);
END;

Benefits

Customization: Allows for better customization of the XML output, making it easier to conform to specific schema requirements or integrate with other systems that expect a particular structure.

Clarity and Readability: Improves the clarity and readability of the XML document by allowing for more descriptive and meaningful tag names.

Integration: Facilitates easier integration with external systems and applications that consume XML, by allowing the XML structure to be tailored to specific needs.

Conclusion

The DBMS_XMLGEN.SETROWSETTAG procedure is a useful tool for customizing the XML output generated from SQL queries in Oracle databases. By allowing developers to specify custom tag names for the rowset elements, it provides greater flexibility and control over the structure of the generated XML, making it easier to meet specific application requirements and integrate with other systems.