Set timestamp on insert when loading CSV [duplicate] - mysql

Question

This question already has answers here:
How can i add date as auto update when import data from csv file?
(2 answers)
Closed 9 years ago.
I have a Timestamp field that is defined to be automatically updated with the CURRENT_TIMESTAMP value.
It works fine when I fire a query, but when I import a csv (which I'm forced to do since one of the fields is longtext) , the update does not work.
I have tried to:
Give timestamp column as now() function in csv
Manually enter timestamp like 2013-08-08 in the csv
Both the approaches do not work

Answer 1

From what I gather, after updating your question, is that you're actually updating rows using a CSV, and expect the ON UPDATE clause to set the value of your timestamp field to be updated.
Sadly, when loading a CSV into a database you're not updating, but inserting data, and overwriting existing records. At least, when using a LOCAL INFILE, if the INFILE isn't local, the query will produce an error, if it's a local file, these errors (duplicates) will produce warnings and the operation will continue.
If this isn't the case for you, perhaps consider following one of the examples on the doc pages:
LOAD DATA INFILE 'your.csv'
INTO TABLE tbl
(field_name1, field_name2, field_name3)
SET updated = NOW()
FIELDS TERMINATED BY ','
OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY ('\n');
Just in case you can't/won't/forget to add additional information, loading a csv int a MySQL table is quite easy:
LOAD DATA
LOCAL INFILE '/path/to/file/filename1.csv'
INTO TABLE db.tbl
FIELDS TERMINATED BY ','
OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY '\n'
(`field_name1`,`field_name2`,`field_name3`)
If you create a table along the lines of:
CREATE TABLE tbl(
id INT AUTO_INCREMENT PRIMARY KEY, -- since your previous question mentioned auto-increment
field_name1 VARCHAR(255) NOT NULL PRIMARY KEY, -- normal fields
field_name2 INTEGER(11) NOT NULL PRIMARY KEY,
field_name3 VARCHAR(255) NOT NULL DEFAULT '',
-- when not specified, this field will receive current_timestamp as value:
inserted TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
-- if row is updated, this field will hold the timestamp of update-time
updated TIMESTAMP NOT NULL DEFAULT 0
ON UPDATE CURRENT_TIMESTAMP
)ENGINE = INNODB
CHARACTER SET utf8 COLLATE utf8_general_ci;
This query is untested, so please be careful with it, it's just to give a general idea of what you need to do to get the insert timestamp in there.
This example table will work like so:
> INSERT INTO tbl (field_name1, field_name2) VALUES ('foobar', 123);
> SELECT FROM tbl WHERE field_name1 = 'foobar' AND field_name2 = 123;
This will show:
+---------------------+---------------------+---------------------+---------------------+---------------------+---------------------+
| id | field_name1 | field_name2 | field_name3 | inserted | updated |
+---------------------+---------------------+---------------------+---------------------+---------------------+---------------------+
| 1 | foobar | 123 | | 2013-08-07 00:00:00 | 0000-00-00 00:00:00 |
+---------------------+---------------------+---------------------+---------------------+---------------------+---------------------+
As you can see, because we didn't explicitly insert a value into the last three fields, MySQL used their DEFAULT values. For field_name3, an empty string was used, for inserted, the default was CURRENT_TIMESTAMP, for updated the default value was 0 which, because the field-type is TIMESTAMP is represented by the value 0000-00-00 00:00:00. If you were to run the following query next:
UPDATE tbl
SET field_name3 = 'an update'
WHERE field_name1 = 'foobar'
AND field_name2 = 123
AND id = 1;
The row would look like this:
+---------------------+---------------------+---------------------+---------------------+---------------------+---------------------+
| id | field_name1 | field_name2 | field_name3 | inserted | updated |
+---------------------+---------------------+---------------------+---------------------+---------------------+---------------------+
| 1 | foobar | 123 | an update | 2013-08-07 00:00:00 | 2013-08-07 00:00:20 |
+---------------------+---------------------+---------------------+---------------------+---------------------+---------------------+
that's all. Some basics can be found here, on mysqltutorial.org, but best keep the official manual ready. It's not bad once you get used to it.
Perhaps this question might be worth a quick peek, too.