I was extending the Openads database abstraction layer last night, to ensure that creation of databases works correctly. I'm no PostgreSQL expert, but it seems that it won't let you issue DDL/DML commands unless you have connected to a database first - so if you want to create a database, you have to connect to a different, already existing database first.
Luckily, the PEAR::MDB2 library will connect you to the "default" database for a database server if you specify no database name in the DSN. (For PostgreSQL, this is the "template1" database.)
This was all well and good, until I tried to then connect to my newly created database, and all I'd get back was the previous connection to "template1". It turns out that the MDB2::singleton() method compared the DSN array of the database you want to connect to with any DSN arrays of previous connections it has made by using the array_diff() function.
Alas, when creating a connection with no database name results in the DSN having the boolean false for the database name field - and because other items in the new DSN array were also false in my case (for example, the "mode" of the connection" was false), the array_diff() function returned no differences. Oops!
Changing to the array_diff_assoc() function solved the problem.
