Timestamp with implicit default value is deprecated error in MySQL 5.6

install MySQL when , Yes warning:

​ ​?​​

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101

​​[[email protected] mysql]# scripts/mysql_install_db --user=mysql​​ ​​Installing MySQL system tables...2015-08-13 14:20:09 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).​​ ​​2015-08-13 14:20:09 0 [Note] ./bin/mysqld (mysqld 5.6.26) starting as process 1934 ...​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: Using mutexes to ref count buffer pool pages​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: The InnoDB memory heap is disabled​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: Mutexes and rw_locks use InnoDB's own implementation​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: Memory barrier is not used​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: Compressed tables use zlib 1.2.3​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: Using Linux native AIO​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: Not using CPU crc32 instructions​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: Initializing buffer pool, size = 128.0M​​ ​​2015-08-13 14:20:09 1934 [Note] InnoDB: Completed initialization of buffer pool​​ ​​2015-08-13 14:20:10 1934 [Note] InnoDB: The first specified data file ./ibdata1 did not exist: a new database to be created!​​ ​​2015-08-13 14:20:10 1934 [Note] InnoDB: Setting file ./ibdata1 size to 12 MB​​ ​​2015-08-13 14:20:10 1934 [Note] InnoDB: Database physically writes the file full: wait...​​ ​​2015-08-13 14:20:10 1934 [Note] InnoDB: Setting log file ./ib_logfile101 size to 48 MB​​ ​​2015-08-13 14:20:11 1934 [Note] InnoDB: Setting log file ./ib_logfile1 size to 48 MB​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: Renaming log file ./ib_logfile101 to ./ib_logfile0​​ ​​2015-08-13 14:20:12 1934 [Warning] InnoDB: New log files created, LSN=45781​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: Doublewrite buffer not found: creating new​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: Doublewrite buffer created​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: 128 rollback segment(s) are active.​​ ​​2015-08-13 14:20:12 1934 [Warning] InnoDB: Creating foreign key constraint system tables.​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: Foreign key constraint system tables created​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: Creating tablespace and datafile system tables.​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: Tablespace and datafile system tables created.​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: Waiting for purge to start​​ ​​2015-08-13 14:20:12 1934 [Note] InnoDB: 5.6.26 started; log sequence number 0​​ ​​2015-08-13 14:20:14 1934 [Note] Binlog end​​ ​​2015-08-13 14:20:14 1934 [Note] InnoDB: FTS optimize thread exiting.​​ ​​2015-08-13 14:20:14 1934 [Note] InnoDB: Starting shutdown...​​ ​​2015-08-13 14:20:16 1934 [Note] InnoDB: Shutdown completed; log sequence number 1625977​​ ​​OK​​ ​​Filling help tables...2015-08-13 14:20:16 0 [Warning] TIMESTAMP with implicit DEFAULT value is deprecated. ​​ ​​Please use --explicit_defaults_for_timestamp server option (see documentation for more details).​​ ​​2015-08-13 14:20:16 0 [Note] ./bin/mysqld (mysqld 5.6.26) starting as process 1957 ...​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Using mutexes to ref count buffer pool pages​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: The InnoDB memory heap is disabled​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Mutexes and rw_locks use InnoDB's own implementation​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Memory barrier is not used​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Compressed tables use zlib 1.2.3​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Using Linux native AIO​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Not using CPU crc32 instructions​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Initializing buffer pool, size = 128.0M​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Completed initialization of buffer pool​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Highest supported file format is Barracuda.​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: 128 rollback segment(s) are active.​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: Waiting for purge to start​​ ​​2015-08-13 14:20:16 1957 [Note] InnoDB: 5.6.26 started; log sequence number 1625977​​ ​​2015-08-13 14:20:17 1957 [Note] Binlog end​​ ​​2015-08-13 14:20:17 1957 [Note] InnoDB: FTS optimize thread exiting.​​ ​​2015-08-13 14:20:17 1957 [Note] InnoDB: Starting shutdown...​​ ​​2015-08-13 14:20:18 1957 [Note] InnoDB: Shutdown completed; log sequence number 1625987​​ ​​OK​​ ​​To start mysqld at boot time you have to copy​​ ​​support-files/mysql.server to the right place for your system​​ ​​PLEASE REMEMBER TO SET A PASSWORD FOR THE MySQL root USER !​​ ​​To do so, start the server, then issue the following commands:​​ ​​./bin/mysqladmin -u root password 'new-password'​​ ​​./bin/mysqladmin -u root -h localhost.localdomain password 'new-password'​​ ​​Alternatively you can run:​​ ​​./bin/mysql_secure_installation​​ ​​which will also give you the option of removing the test​​ ​​databases and anonymous user created by default. This is​​ ​​strongly recommended for production servers.​​ ​​See the manual for more instructions.​​ ​​You can start the MySQL daemon with:​​ ​​cd . ; ./bin/mysqld_safe &​​ ​​You can test the MySQL daemon with mysql-test-run.pl​​ ​​cd mysql-test ; perl mysql-test-run.pl​​ ​​Please report any problems at ​ ​http://bugs.mysql.com/​​​ ​​The latest information about MySQL is available on the web at​​ ​​ ​http://www.mysql.com​​​ ​​Support MySQL by buying support/licenses at ​ ​http://shop.mysql.com​​​ ​​New default config file was created as ./my.cnf and​​ ​​will be used by default by the server when you start it.​​ ​​You may edit this file to change server settings​​ ​​WARNING: Default config file /etc/my.cnf exists on the system​​ ​​This file will be read by default by the MySQL server​​ ​​If you do not want to use this, either remove it, or use the​​ ​​--defaults-file argument to mysqld_safe when starting the server​​ ​​[[email protected] mysql]#​​

[Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).

The reason is from 5.6 Start ,timestamp The default behavior of is already deprecated 了 .

stay MySQL 5.6.6 Before ,TIMESTAMP Default behavior of ：

•TIMESTAMP Column if not explicitly stated NULL attribute , The default is NOT NULL.（ And other data types , If not, declare as NOT NULL, allows NULL value .） Set up TIMESTAMP The column value of is NULL, Will be automatically stored as the current timestamp.

• The first one in the list TIMESTAMP Column , If there is no statement NULL attribute 、DEFAULT perhaps ON UPDATE, It will be assigned automatically DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP attribute .

• The second in the table TIMESTAMP Column , If not stated as NULL perhaps DEFAULT Clause , Automatically assigned by default '0000-00-00 00:00:00′. The value of the column is not specified when the row is inserted , This column is assigned by default '0000-00-00 00:00:00′, And there's no warning .

To turn off the warning , The following parameters need to be added ：

​ ​?​​

1 2	​​[mysqld]​​ ​​explicit_defaults_for_timestamp=true​​

restart MySQL Then the error disappears , At this time TIMESTAMP Their behavior is as follows ：

•TIMESTAMP If no statement is displayed NOT NULL, Is allowed NULL It's worth it , You can directly set it to NULL, There is no default fill behavior .

•TIMESTAMP No default assignment DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP attribute .

• Declare as NOT NULL And there is no default clause TIMESTAMP Columns have no default values . Insert columns into the data table , I didn't give it to TIMESTAMP When a column is assigned a value , If it's strict SQL Pattern , Will throw out a A mistake , If strictly SQL Mode is not enabled , The column is assigned to '0000-00-00 00:00:00′, There's also a warning .（ This sum MySQL It's the same with other time types of data , Such as DATETIME）

（ See ：​ ​//www.jb51.net/article/71054.htm​​）

That is to say explicit_defaults_for_timestamp Shut down the timestamp Type field locks have some strange default behavior , After adding this parameter , If you still need to help timestamp Type specifies the default behavior , Then you need to display the specification displayed when creating the table .explicit_defaults_for_timestamp That's what it means ： The display specifies that the default value is timestamp Type field .