Duplicate column and add an automatic extension with mySQL. How?

I have two columns with mySQL:

"part_no"

"pdf_link"

I need the "pdf_link" column to automatic开发者_开发技巧ally grab/duplicate the "part_no" value and add a .pdf extension on the end.

For example: If part_no = 00-12345-998, then pdf_link = 00-12345-998.pdf

I need this to happen every time I insert.

I appreciate the help.

Erik

you can achive this effect by using triggers I think.

http://dev.mysql.com/doc/refman/5.0/en/trigger-syntax.html

CREATE TRIGGER ins_pdf AFTER INSERT ON MY_TABLE SET @pdf_link = concat(@part_no,'.pdf')

Why store this extra computed information in the database? You can do this in the query when you pull it out, or, if needed, you could make a view that does it only as-needed.

Example pseudo query (my brain hurts right now, so this is only an example):

select concat(`part_no`, ".pdf") as `pdf_link` from `parts`;

If you really need this, you could use a trigger to duplicate the data ans add the extra string.