I have to "add" data to some area that already consists of data without removing what is presently there. For instance when the area consists of HTML, I have to add more HTML towards the area. It is possible to SQL call that is going to do this or should i call the information for the reason that area, concatenate the brand new data towards the existing data, and reload it in to the database?

UPDATE Table SET Field=CONCAT(Field,'your extra html');
UPDATE myTable SET html=concat(html,'<b>More HTML</b>') WHERE id='10' 

... for instance. Your WHERE could be different obviously.