I'm having issues executing the following MySQL statement with the ocaml-mysql (latest version) library:
let dump_to_db text =
let insert = P.create db (s "INSERT INTO Temperature VALUES (?,?,?,?)") in
ignore (P.execute insert [| "NULL"; "xxx.xxx.xxx.xxx"; text ; "CURRENT_TIMESTAMP" |])
My problem is that the timestamp field is not set correctly. Apparently, whatever I write into the last field (might it be "CURRENT_TIMESTAMP" or simply "NULL"), I'm not able to get the proper outcome.
What happens is that the query get executed and what I see inside the table is a NULL-filled Timestamp field (even tho I have no idea how it can be possible because is defined as a NOT NULL column).
My table structure follows:
CREATE TABLE `Temperature` (
`ID` bigint(20) NOT NULL AUTO_INCREMENT,
`IP` varchar(100) DEFAULT NULL,
`Value` varchar(100) DEFAULT NULL,
`Timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=5 DEFAULT CHARSET=latin1
Prepared.execute takes array with values not arbitrary expressions (function calls). String value "CURRENT_TIMESTAMP" gets converted into timestamp and as it is not recognized as valid number is turned into zero.
Pass NULL properly and it will be default initialized according to CREATE TABLE :
P.execute_null insert [| None; Some "xxx.xxx.xxx.xxx"; Some text ; None |]
Related
I ran the following statement in our test mysql database, it works properly. However, when I ran it in production, I got all rows, including those of CLASS = 'ClassName', updated with XML value set to 0 !
UPDATE table_name c set c.XML= REPLACE (c.XML, '<flag_name>false</flag_name>', '')
WHERE c.CLASS = 'ClassName'
I want to know the reason behind this strange behaviour?
Note: The table structure is as follows:
CREATE TABLE `table_name` (
`ID` int(10) unsigned NOT NULL AUTO_INCREMENT,
`CLASS` varchar(250) NOT NULL,
`XML` mediumtext NOT NULL,
PRIMARY KEY (`ID`)
) ENGINE=InnoDB AUTO_INCREMENT=23510 DEFAULT CHARSET=utf8;
The expected behaviour is to remove the targeted tag
my table structure is
CREATE TABLE IF NOT EXISTS `emp` (
`id` int(3) NOT NULL AUTO_INCREMENT,
`name` varchar(11) DEFAULT NULL,
`age` varchar(31) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;
My query is :
INSERT INTO `emp` (`id`, `name`) VALUES ('1', 'prashant');
This is working with all the MYSQL versions below 5.7, but not working with MYSQL version 5.7.12-0ubuntu1
Getting error :
#1364 - Field 'age' doesn't have a default value
What is new in this version ??
Try it on mysql version below 5.7 ,you will see the difference.
Thanks :-)
It would be a huge surprise if this worked in any version of mysql at all. Copy paste this into sqlfiddle.com (mysql 5.6 or 5.5) and confirm for yourself.
age is defined as varchar(31) and not null. Thus your insert statement should have a value for that column. Or you should give it a default value. While you are at it, change it to a more appropriate data type.
CREATE TABLE IF NOT EXISTS `emp` (
`id` int(3) NOT NULL AUTO_INCREMENT,
`name` varchar(11) DEFAULT NULL,
`age` int(3) NOT NULL default 0,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=2 ;
Updated:
Thinking about this some more I think you have switched off Strict Mode in your older version of mysql
Strict mode controls how MySQL handles invalid or missing values in
data-change statements such as INSERT or UPDATE. A value can be
invalid for several reasons. For example, it might have the wrong data
type for the column, or it might be out of range. A value is missing
when a new row to be inserted does not contain a value for a non-NULL
column that has no explicit DEFAULT clause in its definition. (For a
NULL column, NULL is inserted if the value is missing.) Strict mode
also affects DDL statements such as CREATE TABLE.
So my original statement is wrong! With string mode off, the default for varchar is probably '' (not sure though never used strict mode off)
In your table age described as not null.
`age` varchar(31) NOT NULL
So, it is required field for insert.
The NOT NULL constraint enforces a field to always contain a value. This means that you cannot insert a new record, or update a record without adding a value to this field.You have to give value for age also in your insert query because it cannot be null.For eg:-
insert into emp(`id`,`name`,`age`) values('1','rahul','26')
hope this helps!!.Comment for further query
why do i get invalid default value error for the variable "last_updated"?
note i am getting this error while i run the following code in MySQL console in phpmyadmin
CREATE TABLE IF NOT EXISTS `articles` (
`article_id` int(10) NOT NULL AUTO_INCREMENT,
`content_id` int(10) NOT NULL,
`article_body` text NOT NULL,
`last_updated` datetime NOT NULL DEFAULT CURRENT_TIMESTAMP,
PRIMARY KEY (`article_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=532 ;
You need to change the last_updated column's data type to timestamp rather than datetime. This will allow the use of CURRENT_TIMESTAMP as a default value.
As it happens, these two data types are represented in the same format YYYY-MM-DD HH:MM:SS. So if/when you use the data, you shouldn't run into any troubles.
Check your MySQL server version, CURRENT_TIMESTAMP is allowed since version 5.6.5 as DEFAULT for DATETIME type, otherwise you should use either TIMESTAMP type or maintain it outside.
I have a weird problem with a MySQL users table. I have quickly created a simplified version as a testcase.
I have the following table
CREATE TABLE IF NOT EXISTS `users` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`identity` varchar(255) NOT NULL,
`credential` varchar(255) NOT NULL,
`credentialSalt` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=ucs2 AUTO_INCREMENT=2 ;
INSERT INTO `users` (`id`, `identity`, `credential`, `credentialSalt`) VALUES
(1, 'test', '7288edd0fc3ffcbe93a0cf06e3568e28521687bc', '123');
And I run the following query
SELECT id,
IF (credential = SHA1(CONCAT('test', credentialSalt)), 1, 0) AS dynamicSaltMatches,
credentialSalt AS dynamicSalt,
SHA1(CONCAT('test', credentialSalt)) AS dynamicSaltHash,
IF (credential = SHA1(CONCAT('test', 123)), 1, 0) AS staticSaltMatches,
123 AS staticSalt,
SHA1(CONCAT('test', 123)) AS staticSaltHash
FROM users
WHERE identity = 'test'
Which gives me the following result
The dynamic salt does NOT match while the static salt DOES match.
This is blowing my mind. Can someone help me point out the cause of this?
My MySQL version is 5.5.29
It's because of the default character set of your table. You appear to be running this on a UTF8 database and something in SHA1() is having problems with the differing character sets.
If you change your table declaration to the following it will match again:
CREATE TABLE IF NOT EXISTS `users` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`identity` varchar(255) NOT NULL,
`credential` varchar(255) NOT NULL,
`credentialSalt` varchar(255) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=2 ;
SQL Fiddle
As robertklep commented explicitly casting your string to a character will also work, basically ensure you're using the same characterset when doing comparisons using SHA1()
As the encryption functions documentation says:
Many encryption and compression functions return strings for which the result might contain arbitrary byte values. If you want to store these results, use a column with a VARBINARY or BLOB binary string data type. This will avoid potential problems with trailing space removal or character set conversion that would change data values, such as may occur if you use a nonbinary string data type (CHAR, VARCHAR, TEXT).
This was changed in version 5.5.3:
As of MySQL 5.5.3, the return value is a nonbinary string in the connection character set. Before 5.5.3, the return value is a binary string; see the notes at the beginning of this section about using the value as a nonbinary string.
I want to set a uuid value to "id" field via function uuid().
And I do not want to use as Trigger.
CREATE TABLE `test` (
`id` VARCHAR(36) NOT NULL DEFAULT uuid(),
`username` VARCHAR(250) NULL DEFAULT NULL,
`values` VARCHAR(250) NULL DEFAULT NULL ,
PRIMARY KEY (`id`)
)
ENGINE=InnoDB;
the spec is quite explicit on this: http://dev.mysql.com/doc/refman/5.0/en/data-type-defaults.html
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.
so either you use triggers, calculate the value beforehand (e.g. in php) or you use some other database, e.g. oracle might support it.