The XMLCONCAT function in Oracle PL/SQL is used for concatenating XML fragments into a single XML document. This function takes multiple XML fragments as input and combines them into a single XML document. This can be useful in scenarios where you need to aggregate or concatenate XML data from different sources or create a more complex XML structure.
Syntax
The basic syntax of the XMLCONCAT function is as follows:
XMLCONCAT(xml_frag1, xml_frag2, ..., xml_fragN)
Here, xml_frag1, xml_frag2, …, xml_fragN are the XML fragments that you want to concatenate. The function returns a single XML document that represents the concatenation of the input fragments.
Example
Let’s illustrate this with an example. Suppose you have two XML fragments:
DECLARE
xml_fragment1 XMLTYPE := XMLTYPE('<employee><id>1</id><name>John</name></employee>');
xml_fragment2 XMLTYPE := XMLTYPE('<employee><id>2</id><name>Jane</name></employee>');
concatenated_xml XMLTYPE;
BEGIN
select XMLCONCAT(xml_fragment1, xml_fragment2)
into concatenated_xml
from dual;
DBMS_OUTPUT.PUT_LINE(concatenated_xml.getStringVal());
END;
In this example, xml_fragment1 and xml_fragment2 represent two XML fragments, each containing information about an employee. The XMLCONCAT function is used to concatenate these fragments into a single XML document, which is then printed using DBMS_OUTPUT.PUT_LINE.
The output would be:
<employee><id>1</id><name>John</name></employee><employee><id>2</id><name>Jane</name></employee>
As you can see, the XMLCONCAT function has combined the two XML fragments into a single XML document. It’s important to note that the order of the input fragments is maintained in the resulting XML document.
This function can be particularly useful in situations where you need to aggregate data from different sources or build more complex XML structures in your PL/SQL code. Keep in mind that this is just a basic example, and you can use the XMLCONCAT function with more than two XML fragments if needed.