The MySQL trigger is a database object that is associated with a table. It will be activated when a defined action is executed for the table (when you run the following MySQL statements on the table : INSERT, UPDATE and DELETE ).
Command apt-get build-dep php5 failed with error message libmysqlclient-dev : Depends: libmysqlclient18. Fix error Depends libmysqlclient18 with MariaDB. You can fix the issue by installing the package libmariadbclient-dev.