Routine to convert custom post meta from old to new value

Question

I have two custom post meta objects that have been applied to all pages and posts in my sites. The names are MyCustomHeader and MyCustomTitle and I have one of these assigned to each post and page in my site.

I've just decided to change the names of these two meta objects so that they do not appear in the Custom Fields fieldset. I've done this by placing an underscore character before them. This changes the values to "_MyCustomHeader" and "_MyCustomTitle".

In order to account for the sites that have numerous references to the old post meta names, I need to create a routine that runs once (either in the form of a plugin or a script in my theme options that only executes on theme activation) that goes through the WP database and converts every value that was "MyCustomHeader to "_MyCustomHeader" and also "MyCustomTitle" to "_MyCustomTitle".

Any help much appreciated.

• scott

Answer 1

You can run the following sql queries:

update wp_postmeta set meta_key=replace(meta_key,'MyCustomHeader','_MyCustomHeader') where meta_key like "MyCustomHeader";
update wp_postmeta set meta_key=replace(meta_key,'MyCustomTitle','_MyCustomTitle') where meta_key like "MyCustomTitle";