MySQL 5.6 中TIMESTAMP with implicit DEFAULT value is deprecat_MySQL
安装MySQL时，有warning:
[root@localhost 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 [root@localhost mysql]#
[Warning] TIMESTAMP with implicit DEFAULT value is deprecated. Please use --explicit_defaults_for_timestamp server option (see documentation for more details).
其原因是从 5.6开始，timestamp 的默认行为已经是 deprecated 了。
在MySQL 5.6.6之前，TIMESTAMP的默认行为：
•TIMESTAMP列如果没有明确声明NULL属性，默认为NOT NULL。（而其他数据类型，如果没有显示声明为NOT NULL，则允许NULL值。）设置TIMESTAMP的列值为NULL，会自动存储为当前timestamp。
•表中的第一个TIMESTAMP列，如果没有声明NULL属性、DEFAULT或者 ON UPDATE，会自动分配 DEFAULT CURRENT_TIMESTAMP和ON UPDATE CURRENT_TIMESTAMP 属性。
•表中第二个TIMESTAMP列，如果没有声明为NULL或者DEFAULT子句，默认自动分配'0000-00-00 00:00:00′。插入行时没有指明改列的值，该列默认分配'0000-00-00 00:00:00′，且没有警告。
要关闭警告，需要加入下面的参数：
[mysqld] explicit_defaults_for_timestamp=true
重启MySQL后错误消失，这时TIMESTAMP的行为如下：
•TIMESTAMP如果没有显示声明NOT NULL，是允许NULL值的，可以直接设置改列为NULL，而没有默认填充行为。
•TIMESTAMP不会默认分配DEFAULT CURRENT_TIMESTAMP 和 ON UPDATE CURRENT_TIMESTAMP属性。
•声明为NOT NULL且没有默认子句的TIMESTAMP列是没有默认值的。往数据表中插入列，又没有给TIMESTAMP列赋值时，如果是严格SQL模式，会抛出一 个错误，如果严格SQL模式没有启用，该列会赋值为'0000-00-00 00:00:00′，同时出现一个警告。（这和MySQL处理其他时间类型数据一样，如DATETIME）
（参见：http://www.bitsCN.com/article/71054.htm）
也就是 explicit_defaults_for_timestamp 关闭了 timestamp 类型字段锁拥有的一些会让人感到奇怪的默认行为，加入了该参数之后，如果还需要为 timestamp类型的字段指定默认行为，那么就需要显示的在创建表时显示的指定。explicit_defaults_for_timestamp 也就是这个意思：显示指定默认值为timestamp类型的字段。
Hot AI Tools
Undresser.AI Undress
AI-powered app for creating realistic nude photos
AI Clothes Remover
Online AI tool for removing clothes from photos.
Undress AI Tool
Undress images for free
Clothoff.io
AI clothes remover
Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!
Hot Article
Hot Tools
Notepad++7.3.1
Easy-to-use and free code editor
SublimeText3 Chinese version
Chinese version, very easy to use
Zend Studio 13.0.1
Powerful PHP integrated development environment
Dreamweaver CS6
Visual web development tools
SublimeText3 Mac version
God-level code editing software (SublimeText3)
Hot Topics
1664
14
1423
52
1318
25
1269
29
1248
24
MySQL's Role: Databases in Web Applications
Apr 17, 2025 am 12:23 AM
The main role of MySQL in web applications is to store and manage data. 1.MySQL efficiently processes user information, product catalogs, transaction records and other data. 2. Through SQL query, developers can extract information from the database to generate dynamic content. 3.MySQL works based on the client-server model to ensure acceptable query speed.
Explain the role of InnoDB redo logs and undo logs.
Apr 15, 2025 am 12:16 AM
InnoDB uses redologs and undologs to ensure data consistency and reliability. 1.redologs record data page modification to ensure crash recovery and transaction persistence. 2.undologs records the original data value and supports transaction rollback and MVCC.
MySQL: An Introduction to the World's Most Popular Database
Apr 12, 2025 am 12:18 AM
MySQL is an open source relational database management system, mainly used to store and retrieve data quickly and reliably. Its working principle includes client requests, query resolution, execution of queries and return results. Examples of usage include creating tables, inserting and querying data, and advanced features such as JOIN operations. Common errors involve SQL syntax, data types, and permissions, and optimization suggestions include the use of indexes, optimized queries, and partitioning of tables.
MySQL's Place: Databases and Programming
Apr 13, 2025 am 12:18 AM
MySQL's position in databases and programming is very important. It is an open source relational database management system that is widely used in various application scenarios. 1) MySQL provides efficient data storage, organization and retrieval functions, supporting Web, mobile and enterprise-level systems. 2) It uses a client-server architecture, supports multiple storage engines and index optimization. 3) Basic usages include creating tables and inserting data, and advanced usages involve multi-table JOINs and complex queries. 4) Frequently asked questions such as SQL syntax errors and performance issues can be debugged through the EXPLAIN command and slow query log. 5) Performance optimization methods include rational use of indexes, optimized query and use of caches. Best practices include using transactions and PreparedStatemen
Why Use MySQL? Benefits and Advantages
Apr 12, 2025 am 12:17 AM
MySQL is chosen for its performance, reliability, ease of use, and community support. 1.MySQL provides efficient data storage and retrieval functions, supporting multiple data types and advanced query operations. 2. Adopt client-server architecture and multiple storage engines to support transaction and query optimization. 3. Easy to use, supports a variety of operating systems and programming languages. 4. Have strong community support and provide rich resources and solutions.
MySQL vs. Other Programming Languages: A Comparison
Apr 19, 2025 am 12:22 AM
Compared with other programming languages, MySQL is mainly used to store and manage data, while other languages such as Python, Java, and C are used for logical processing and application development. MySQL is known for its high performance, scalability and cross-platform support, suitable for data management needs, while other languages have advantages in their respective fields such as data analytics, enterprise applications, and system programming.
MySQL: From Small Businesses to Large Enterprises
Apr 13, 2025 am 12:17 AM
MySQL is suitable for small and large enterprises. 1) Small businesses can use MySQL for basic data management, such as storing customer information. 2) Large enterprises can use MySQL to process massive data and complex business logic to optimize query performance and transaction processing.
How does MySQL index cardinality affect query performance?
Apr 14, 2025 am 12:18 AM
MySQL index cardinality has a significant impact on query performance: 1. High cardinality index can more effectively narrow the data range and improve query efficiency; 2. Low cardinality index may lead to full table scanning and reduce query performance; 3. In joint index, high cardinality sequences should be placed in front to optimize query.
