![]() ![]() ![]() MariaDB does not currently store any time zone identifier with the value of the TIMESTAMP data type. ![]() For example, if a specific time range never occurred in a specific time zone due to daylight savings time, then TIMESTAMP values within that range would be invalid for that time zone. MariaDB validates TIMESTAMP literals against the session's time zone. If a column uses the TIMESTAMP data type, then any inserted values are converted from the session's time zone to Coordinated Universal Time (UTC) when stored, and converted back to the session's time zone when retrieved. In this case, if the column's value is set to NULL, then the column's value will actually be set to NULL. This automatic initialization for NULL values can also be explicitly disabled for a column that uses the TIMESTAMP data type by specifying the NULL attribute for the column. If the column is assigned the NULL value in an INSERT or UPDATE query, then MariaDB will automatically initialize the column's value with the current date and time. MariaDB also has special behavior if NULL is assigned to column that uses the TIMESTAMP data type. If a DEFAULT clause is explicitly specified for a column that uses the TIMESTAMP data type, but an ON UPDATE clause is not specified for the column, then the timestamp value will not automatically change when an UPDATE statement is executed. ![]() This automatic initialization for UPDATE queries can also be explicitly disabled for a column that uses the TIMESTAMP data type by specifying a DEFAULT clause for the column, but no ON UPDATE clause. This automatic initialization for INSERT queries can also be explicitly disabled for a column that uses the TIMESTAMP data type by specifying a constant DEFAULT value. In these clauses, any synonym of CURRENT_TIMESTAMP is accepted, including CURRENT_TIMESTAMP(), NOW(), LOCALTIME, LOCALTIME(), LOCALTIMESTAMP, and LOCALTIMESTAMP(). This automatic initialization for INSERT and UPDATE queries can also be explicitly enabled for a column that uses the TIMESTAMP data type by specifying the DEFAULT CURRENT_TIMESTAMP and ON UPDATE CURRENT_TIMESTAMP clauses for the column. This means that if the column is not explicitly assigned a value in an INSERT or UPDATE query, then MariaDB will automatically initialize the column's value with the current date and time. For the first column that uses the TIMESTAMP data type in a specific table, MariaDB automatically assigns the following properties to the column: MariaDB has special behavior for the first column that uses the TIMESTAMP data type in a specific table when the system variable explicit_defaults_for_timestamp is not set (which is the default until MariaDB 10.10). If no microsecond precision is specified, then 0 is used by default. MariaDB can also store microseconds with a precision between 0 and 6. This means that the TIMESTAMP data type can hold values between ' 00:00:01' ( UTC) and ' 03:14:07' ( UTC). MariaDB stores values that use the TIMESTAMP data type as the number of seconds since ' 00:00:00' ( UTC). MariaDB includes the -mysql56-temporal-format option, on by default, which allows MariaDB to store TIMESTAMPs using the same low-level format MySQL 5.6 uses.įor more information, see Internal Format. The automatic properties only apply to the first TIMESTAMP in the record subsequent TIMESTAMP columns will not be changed. The timestamp field is generally used to define at which moment in time a row was added or updated and by default will automatically be assigned the current datetime when a record is inserted or updated. A timestamp in the format YYYY-MM-DD HH:MM:SS.ffffff. ![]()
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