MySQL -> Oracle Migration

I'd like some input on what considerations there are about developing a solution in MySQL that will ultimately be moved to Oracle. We're inclined to avoid the ODBC functions for better performance. I've seen some debate as to if ODBC actually significantly affects performance negatively. So my questions essentially are: 1) Is migrating from the MySQL -> Oracle functions a reasonable approach vs just using the ODBC functions. 1.5) What about migrating from ODBC functions directly to Oracle functions. 2) Are there already tools that will automate converting PHP code from one to another? 3) If we choose developing on MySQL and migrate to Oracle, are there considerations in how the code should be written to make the migration simpler? For example I found this comment on the PHP site: "It would be nice if we could have a mode to return the row as an object, just like mysql_fetch_object(), what do you think? It would be a lot easier to migrate from mysql to oracle.... :) " Thanks for your input.