TOPIC:

Okay, on my modified upgrade program I had to add:after establishing the connection.
Running the program I then get the following output shown:

Warning: PDOStatement::execute(): SQLSTATE[42000]: Syntax error or access violation: 1142 ALTER command denied to user 'xerteuser'@'localhost' for table 'sitedetails' in /var/www/html/xerte-3.5/jhf.php on line 37
Array ( [0] => 00000 [1] => [2] => )

Line 37 corresponds to the execute statement.

It's odd though because the user does have permissions, and if I run the command by hand as that user, then it works.
So, not sure if I'm a bit closer with this or not!

Found it.

Because I coincidently happened to run into the same problem....

The _db_add_field() function basically is not able to handle fields of type 'text'.

A type text is a blob in mysql, and blob types cannot have a default value, but _db_add_field() tries to set the default value.

So either change the type to a varchar, or modify _db_add_field() to be able to handle text fields.

I haven't touched the code.

Erm... no :-)
I know what you mean about globs not having a default (despite NULL seeming to be an obvious default for text fields). But mysql does not actually object to a TEXT default so long as it is '' (2 single quotes) or set to NULL (not the string "NULL" which _db_add_field does.) Setting any other default does give an error saying that globs/text cannot have a default.
(Tested with mariadb 5.5.56).
I did try setting the field to something other than text (I used char(255)), but it gave the same error.

Okay, the problem was permissions!
The error is confusing because it says

...ALTER command denied to user 'xerteuser'@'localhost' for table...

If I check that users permissions then they have all permissions.
However, in database.php the host is '127.0.0.1', and for that user ('xerteuser'@'127.0.0.1') the permissions are just select, insert etc. So by allowing the user 'xerteuser' @'127.0.0.1' the ALTER permission, the script then works fine in adding the new field.
I guess when I added the field manually from the command line it was because I was seen as being from 'localhost'.

Anyway, problem solved. Many thanks for your help.