Aprial 9th Monday (四月　九日　月曜日)

  Today I created a abstract layer for accessing a database in PHP.  This class includes such operator
 as "connect", "disconnect", "executeQuery", and so forth.  My purpose is to provide a uniform interface
of accessing database.  So, I created two sub classes of that class.  One is to access MySQL database.
Another is to access PostgreSQL database.

  To seek a property sub classes I created a special class to adapt a sub class in according to a argument.
That is a factory class, in acutal fact, it is a adaptation.