I can’t find _mysql module that can found in 1.5.2
Huh? Is that a python module? I don’t remember anything related to that changed in 1.5.4.
yes it’s python my old code has error when i change version from 1.5.2 to 1.5.4
_mysql is the low level Python API to the MySQL database. It is part of the MySQL-Python package, which is, to my knowledge, not part of the Panda3D distribution (neither 1.5.2 nor 1.5.4 or any other version).
I guess that somehow you (or someone else) installed the MySQL module in the Panda3D Python site-packages for 1.5.2. And when un-installing and installing Panda 1.5.4 you simply forgot to install MySQL again.
You can re-install the MySQL package, if you need it. By the way: consider using the MySQLdb module which is the Python DB API 2.0, and not the low-level _mysql module.