MySQL TIMESTAMP (timestamp) detailed explanation

When you create a table that has a type of field timestamp in the table, the statement is generated by default:

CREATE TABLE ' test ' (  ' id ' int (one) default null,  ' ctime ' timestamp not null default Current_timestamp on UPDATE CU Rrent_timestamp) Engine=innodb DEFAULT CHARSET=GBK

Assuming that there are two field types of timestamp, the resulting statement is:

CREATE TABLE ' test ' (  ' id ' INT (one) default null,  ' ctime ' TIMESTAMP not null default Current_timestamp on UPDATE CU Rrent_timestamp,  ' utime ' TIMESTAMP not NULL default ' 0000-00-00 00:00:00 ') engine=innodb default CHARSET=GBK

TIMESTAMP setting defaults are default Current_timestamp,

TIMESTAMP settings as the table changes and your own active update is on update current_timestamp

A table can have at most only one field set Current_timestamp (current time)

1. TIMESTAMP DEFAULT current_timestamp on UPDATE current_timestamp

Refreshes the data column when new records are created and existing records are changed

2. TIMESTAMP DEFAULT Current_timestamp

Set this field to the current time when creating a new record, but do not refresh it when you change it later

3. TIMESTAMP on UPDATE current_timestamp

Set this field to 0 when creating a new record, and refresh it later when you change it

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Source: http://blog.csdn.net/itmyhome1990/article/details/39342245

MySQL TIMESTAMP (timestamp) detailed explanation