[Dbixx-devel] Questions about DatabaseInterface (again)

[Jerry S. <ye...@sp...>]

Hello again,

I have a basic MySQLDatabaseInterface class going.  It can retrieve
simple objects from the database and store them to the database.  I haven't
worked on multiple table support yet.

A couple of questions have arisen out of this:

1. PersistentFactory.createPersistent(DatabaseInterface dbi, Object identifier)
In my implementation of the PersistentFactory interface I have been using
identifier to pass in a string that tells the Factory which record to
retrieve from the database.  It happens to be a String object and in the
Factory I just use the toString() method on the object to use the String in
my search.  Is this the way it was intended to be used?  Is the usage of
the Object being passed in something that the implementor of the
PersistentFactory interface and the user of it have to agree on?


2. PersistentFactory did not have a storePersistent() method like the
diagrams indicate.  I added:
storePersistent(DatabaseInterface dbi, Persistent p)
Sound about right?

3. When storing an object to the database, I don't know when to use an
UPDATE statement and when to use an INSERT statement.  If the object was
retrieved from the database, modified and is now to be put back into the
database, an UPDATE statement should be used.  If it is a brand new object
then an INSERT statement should be used.  How do you tell which one the
object is?  Running another query just to find out if the object is in the
database seems wasteful and if the database allows multiple non-unique 
records then this method would not work.  It seems to me that the Factory
needs to have control over which type of statement is run.  Thoughts?


I'm close to getting the code in a contributable state.  How do
you want it submitted?

Jerry