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;