The CSPM in SPM12 is a major upgrade, and requires the following steps.
1) Create a new database.
2) Update the new database.
Before you start, make sure you have the latest matlab CSPM files, and a recent version of MySQL (preferably 5.6+) and MySQL Workbench (preferably 6.1+). Copy the new files to ...\matlab\spm12b, making sure you get the ...\matlab\spm12b\toolbox\CSPM files.
Create a new database
Save the existing MySQL database to a file (see save page). The SPM8 schema is usually called "sidata." Restore this file into a new database (schema), which you could call "sidata14" (see restore page). For good practice, you may also want to create a MySQL user (say "datauser") and give that user permissions to use the new database (see user permissions page).
Terminology note: what we call "database" is what MySQL calls "Schema."