I have a table that has two TIMESTAMP columns (Creation_Date and Edit_date) that auto fill on INSERT (both columns get CURRENT_TIMESTAMP) and UPDATE (only the Edit_date column is changed)
The action is done by this code:
... CreationDate timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
EditDate timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE
CURRENT_TIMESTAMP, ...
I need to change the type from TIMESTAMP to DATE and have tried:
...
`CREATED_DATE` date NOT NULL DEFAULT '0000-00-00',
`EDITED_DATE` date NOT NULL DEFAULT CURRENT_DATE ON UPDATE CURRENT_DATE,
...
How can I get the same behavior. Any responses would be appreciated.
No its not possible unless you are using mysql 5.6.5
The only option was available until 5.6.5 is to use field type as timestamp and then set a default which is not constant.
The DEFAULT value clause in a data type specification indicates a
default value for a column. With one exception, the default value must
be a constant; it cannot be a function or an expression. This means,
for example, that you cannot set the default for a date column to be
the value of a function such as NOW() or CURRENT_DATE. The exception
is that you can specify CURRENT_TIMESTAMP as the default for a
TIMESTAMP
If you are using mysql 5.6.5 then you can set this behaviour for DATETIME datatype
http://dev.mysql.com/doc/refman/5.6/en/timestamp-initialization.html
Related
I want to have multiple Timestamps in one table for columns DateAdded and DateUpdated. I have this incorrect definition where DateAdded is at '0000-00-00 00:00:00' and only works for DateUpdated.
`DateAdded` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00',
`DateUpdated` timestamp NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
When I try to edit to have 2 Timestamps I get this error:
Incorrect table definition; there can be only one TIMESTAMP column with CURRENT_TIMESTAMP in DEFAULT or ON UPDATE clause
Please help me with correct workaround. I can see the issue is known but I am not seeing a solution anywhere.
I would replace invalid timestamp:
ALTER TABLE tab MODIFY `DateAdded` timestamp DEFAULT CURRENT_TIMESTAMP;
-- or any other valid value
DBFiddle Demo
I have a table with two timestamp fields. They are not nullable. The problem is that whenever I insert null into those fields, the current date is automatically saved, instead of throwing an error saying "Column 'first_data_dt' cannot be null", just like it happens when I insert a value into another non-nullable field.
There are no triggers associated to this table.
Does anybody know why this is happening?
EDIT to add table definition:
CREATE TABLE `ui_mytable` (
`id` int(11) NOT NULL,
`first_data_dt` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
`last_data_dt` timestamp NOT NULL DEFAULT '0000-00-00 00:00:00'
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
I understand now why first_data_dt is updated to the current timestamp anytime I insert null. But what about last_data_dt?
That's what a TIMESTAMP column does:
The TIMESTAMP data type offers automatic initialization and updating to the current date and time (that is, the current timestamp). [...] You can initialize or update any TIMESTAMP column to the current date and time by assigning it a NULL value, unless it has been defined with the NULL attribute to permit NULL values.
Source: MySQL documentation
Maybe you want to use a DATETIME instead?
I tried to alter the table with inserting a new attribute date1 where it will auto set the date for each entry into the table.
When i insert the query
ALTER TABLE `vessellist` ADD `date1` DATE NOT NULL DEFAULT CURRENT_TIMESTAMP FIRST;
It says INVALID DEFAULT VALUE FOR date1
The DEFAULT clause specifies a default value for a column. With one exception, the default value must be a constant; it cannot be a function or an expression. This means, for example, that you cannot set the default for a date column to be the value of a function such as NOW() or CURRENT_DATE. The exception is that you can specify CURRENT_TIMESTAMP as the default for a TIMESTAMP column
http://dev.mysql.com/doc/refman/5.5/en/create-table.html
Creating a database table in MySQL. I have created two fields to grab timestamps.
created_at timestamp default '0000-00-00 00:00:00',
updated_at timestamp default now() on update now(),
When I update the database, both fields are updating to the current timestamp. Any thoughts on how to prevent this from happening? I am not providing the 'created_at' field when I update -- I am also providing 'null' for the updated_at field to auto update.
Depending on the version of MySQL you should be able to use the following for your default value on the updated_at field:
CURRENT_TIMESTAMP on UPDATE CURRENT_TIMESTAMP
Your created_at field should just have CURRENT_TIMESTAMP as the default.
I would also set both to the datatype datetime instead of timestamp.
Timestamp initialisation can be an ugly beast in mysql!
Based on the commment below you have mysql v5.6.4 or earlier:
I can't have two current_timestamps declared without getting an error -- and although it's default is 0 -- it is producing a current timestamp upon creation(without me feeding in the timestamp) – Spencer Rohan
You can have a single timestamp field that are initialised and/or updated to the current timestamp when you insert / update your record. In earlier versions this had to be the 1st timestamp field in the table.
I would simply set the created_at to be a nullable column with a default value of null because according to mysql documentation on timestamp initialization:
In other words, a TIMESTAMP column defined to permit NULL values auto-initializes only if its definition includes DEFAULT CURRENT_TIMESTAMP
By changing the default value to null you go around any problems you may have with zero dates and various sql modes.
created_at timestamp null default null,
Following is my SQL query, it throws an error:-
CREATE TABLE IF NOT EXISTS USER_PROFILE(Id INT PRIMARY KEY AUTO_INCREMENT, date DATETIME NOT NULL DEFAULT NOW) ;
It says Invalid default value for 'date'.
I've tried synonyms for NOW() as well, namely CURRENT_TIMESTAMP, but still the same error.
How can I create a column date with default value current time?
On the documentation page, it says to assign this way
CREATE TABLE t1 (
ts TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
dt DATETIME DEFAULT CURRENT_TIMESTAMP
);
From the document
The DEFAULT value clause in a data type specification indicates a
default value for a column. With one exception, the default value must
be a constant; it cannot be a function or an expression. This means,
for example, that you cannot set the default for a date column to be
the value of a function such as NOW() or CURRENT_DATE. The exception
is that you can specify CURRENT_TIMESTAMP as the default for TIMESTAMP
and DATETIME columns
So no function is allowed in the default value hence the first query is failing.
Again from the document
As of MySQL 5.6.5, TIMESTAMP and DATETIME columns can be automatically
initializated and updated to the current date and time (that is, the
current timestamp). Before 5.6.5, this is true only for TIMESTAMP, and
for at most one TIMESTAMP column per table. The following notes first
describe automatic initialization and updating for MySQL 5.6.5 and up,
then the differences for versions preceding 5.6.5.
Before 5.6.5, this is true only for TIMESTAMP
So your mysql version is less than 5.6.5 hence the 2nd query is failing too.
So you need to create the table as
CREATE TABLE IF NOT EXISTS
USER_PROFILE
(
Id INT PRIMARY KEY AUTO_INCREMENT,
date TIMESTAMP DEFAULT CURRENT_TIMESTAMP
) ;
It might be that DATE, as a reserved word, is confusing it by the time it gets to the DEFAULT clause. Try a different name and if that works, try quoting "date".