Mysql workbench does not provide a way to easily rename a database.
However,you could use those commands in the terminal
mysqldump -u username -p -v olddatabase > olddbdump.sql mysqladmin -u username -p create newdatabase mysql -u username -p newdatabase < olddbdump.sql
Or
SELECT concat('RENAME TABLE $1.',table_name, ' TO $2.',table_name, ';')
FROM information_schema.TABLES
WHERE table_schema='$1';
($1 and $2 are source and target respectively)