set @@global.sql_mode='STRICT_TRANS_TABLES,NO_ZERO_DATE,NO_ENGINE_SUBSTITUTION';
set @@session.sql_mode='STRICT_TRANS_TABLES,NO_ZERO_DATE,NO_ENGINE_SUBSTITUTION';

create table app_logs(
id int not null auto_increment primary key,
log_tm timestamp not null,
log_info varchar(64) not null)
engine=innodb,charset=utf8;

insert into app_logs(log_tm,log_info) values(now(),'log_info_1');
insert into app_logs(log_tm,log_info) values('2016-12-01','log_info_2');

insert into app_logs(log_tm,log_info) values('2016-12-00','log_info_2');
ERROR 1292 (22007): Incorrect datetime value: '2016-12-00' for column 'log_tm' at row 1