MySQL doesn’t support XML data types like Microsoft SQL Server or PostgreSQL.

Many times it is required to store multiple nodes of data into a single column, in the form of XML.

In the MySQL, You have to store XML in CLOB (Character Large Object) data type.

MySQL provides different types of XML function so using those functions, we can parse the XML data very easily.

Below is a full demonstration on storing and retrieval of XML data:

First store XML data like any other string:

CREATE DATABASE `Employee`;

CREATE TABLE Employee.XMLTest
(
	XMLDATA TEXT
);

INSERT INTO Employee.XMLTest 
VALUES
(
   '<Students>
      <RollNumber>1</RollNumber>
      <Name>Anvesh</Name>
      <RollNumber>2</RollNumber>
      <Name>Neevan</Name>
   </Students>'
);

Second, Parsing this data using below stored procedure:

DELIMITER $$
CREATE PROCEDURE Employee.usp_ParseXMLData()
BEGIN
    DECLARE i INT DEFAULT 1;
    DECLARE XMLText TEXT;
    DECLARE RNumber VARCHAR(50) ;   
    DECLARE RName VARCHAR(50);      
	    
    SET XMLText = (SELECT XMLDATA FROM Employee.XMLTest);        
  
    CREATE TEMPORARY TABLE Employee.TempXMLData 
    (    
        RollNumber VARCHAR(50)
        ,Name VARCHAR(50)
    ); 	
        
    SET RNumber = ExtractValue(XMLText, '//RollNumber[$i]');   
		             
    WHILE RNumber != "" DO                       
        SET RNumber = ExtractValue(XMLText, '//RollNumber[$i]');   
        SET RName = ExtractValue(XMLText, '//Name[$i]');          

	INSERT INTO Employee.TempXMLData 
	SELECT RNumber, RName; 	
        SET i = i+1;  	
    END WHILE;         
    SELECT 
	RollNumber
        ,Name
    FROM Employee.TempXMLData
    WHERE RollNumber <>'';   
	
    DROP TABLE Employee.TempXMLData;
END$$
DELIMITER ;

Call this stored procedure and check the result:

CALL Employee.usp_ParseXMLData();

In this post, I am sharing a demonstration on the XML data type of PostgreSQL.

Explain with the sample example.

What is XML Type ?

The XML Data type is used to store XML data. XML is well-formed storage structure of data. You can store multiple nodes into a single XML column. You can store data in hierarchical format.

E.g,

User preferences table, in which User can select multiple preferences and even User can create custom choices for them.

Now, how you can store this preferences data for those Users.

Simple, create one XML column and store all User preferences id into this. like,

<preferences><id>1</id><id>2</id><id>4</id></preferences>.

Below is a demonstration of XML with PostgreSQL.

Basically you can store XML data with one child node or with different child node.

CREATE TABLE XMLTEST (Name XML);

INSERT INTO XMLTEST 
VALUES
('
    <Root>
          <Sub>abc</Sub>
          <Sub>xyz</Sub>
          <Sub>pqr</Sub>
          <Sub>cdf</Sub>
   </Root>
');

SELECT *FROM XMLTEST

SELECT unnest(xpath('.//Sub/text()', Name::xml))::text AS XMLDATA FROM XMLTEST;

INSERT INTO XMLTEST VALUES
   ('
     <BasicDetails>
        <Name>Anvesh</Name>
        <City>Hyderabad</City>
        <Gender>Male</Gender>
        <Age>27</Age>
     </BasicDetails> 
   ');

SELECT 
 unnest(xpath('//Name/text()', Name::XML)) AS Name
 ,unnest(xpath('//City/text()', Name::XML)) AS City
 ,unnest(xpath('//Gender/text()', Name::XML)) AS Gender
 ,unnest(xpath('//Age/text()', Name::XML)) AS Age
FROM XMLTEST;