Re: [Phpwiki-talk] wanting to do weird things again

[Jeff D. <da...@da...>]

On Thu, 15 Nov 2001 20:58:17 +0100
"Tara Star" <te...@cl...> wrote:

> See the idea? use the same engine for two different wikis.

Yes, that's exactly the reason we moved the config info from 
lib/config.php into index.php.

> Just one thing:
> 
> when I have to create tables in the db, with:
> 
> mysql -uuser -ppassword dbname <schemas/schema.mysql
> 
> what am I doing exactly?

The command 'mysql -uuser -ppassword dbname' connects to the
mysql server (on localhost) using the username 'user'
and password 'password'.  It then effectively does a 'use dbname;'.

The '< schemas/schema.mysql' feeds the contents of the file
schemas/schema.mysql into the standard input of the 'mysql ...'
command.  Essentially, it causes mysql to execute the SQL commands
in schema.mysql.  Those commands:
 1. Delete any pre-existing tables in the current database which
    are named: page, version, recent, nonempty, or link.
 2. Creates new tables with those names, with schema (columns)
    the way PhpWiki wants them to be.   
Roughly: it erases an PhpWiki data which might be in the selected
database,
and then re-initializes the tables (to any empty wiki).  (Then, the
first time you try to browse the HomePage of an empty wiki, PhpWiki will
load it up with the default pgsrc...)

Since this erases existing data in the selected database, you are
right to be wary of performing this command.

> because I see a file named schema.mysql in the 
> schemas directory... so I guess we're using that, right?

Right.  But only when you run the 'mysql < schema.mysql' command.

> And at the top 
> of this file is written "use DbForWiki1" - I think that was added at 
> some point earlier for trying to get the whole thing to work.

GET RID OF THAT LINE!  It's not necessary, if you leave it there,
then the command you propose above will erase all data in DbForWiki1.
(You must have added it.  There is no "use" line in the stock
version.)

> so, what should I do? try removing the "use DbForWiki1" line and see if 
> wiki1 still works? (do I run any risk of breaking something if I do
that?)

The contents of schema.mysql are only used when you initialize the
database.  You could delete schema.mysql, or edit it in any way you
want now, and it won't break your existing wiki.  (Unless of course
you feed it to mysql again.)

> or should I duplicate schema.mysql into wiki2schema.mysql, and change 
> the "use" line? would this break things later on for wiki2?

Just delete the "use" line.  The only time you should have to
edit schema.mysql is if you set $DBParams['prefix'] to a non-empty
value.  (You would want to do this if you wanted to run two independent
wikis in one mysql database.  Since you have the ability to create 
a second database for the second wiki, that is the better way to go.)

Once you delete the "use" line, then (as you proposed) just:

  mysql -uuser -ppasswd DbForNewWiki < schemas/schema.mysql

Before you do that, if you're paranoid --- it's probably a 
good idea even if you're not --- you might make a backup of
database for your first wiki by doing something like:

  mysqldump -uuser -ppasswd DbForWiki1 > wiki1-backup.mysql