ORA-00059 solution

Error
ORA-00059: maximum number of DB_FILES exceeded

Solution
Check limit that total number of db files
SQL> show parameter db_files;
-- e.g. 250

Edit parameter file:
# add this on bottom
*.db_files=500

Shutdown and startup database:
SQL> shu immediate;
SQL> startup;

Extra:
If database is using spfile:
SQL> show parameter spfile;
-- output should be not empty

Delete spfile under $ORACLE_HOME/dbs directory such as 
"spfileALPERDB.ora"

At last, shutdown and startup database again.