mySQL trigger? causing Error Code: 1048 Column cannot be null - mysql

Question

I have seen similar questions asked but never seen an answer that works for me. I have the following table and trigger definitions...
DROP TRIGGER IF EXISTS c_consumption.newRateHistory;
DROP TABLE IF EXISTS c_consumption.myrate;
DROP TABLE IF EXISTS c_consumption.myratehistory;
USE c_consumption;
CREATE TABLE `myrate` (
`consumerId` varchar(255) DEFAULT NULL,
`durationType` varchar(50) NOT NULL DEFAULT 'DAY',
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`itemId` varchar(50) NOT NULL,
`quantity` double NOT NULL DEFAULT 1.0,
`quantityType` varchar(100) NOT NULL DEFAULT 'GALLON',
`timePeriod` double NOT NULL DEFAULT 1.0,
PRIMARY KEY (`id`),
UNIQUE INDEX `UNIQUE_RATE`
(`itemId` ASC, `consumerId` ASC)
) ENGINE=InnoDB AUTO_INCREMENT=314 DEFAULT CHARSET=utf8;
CREATE TABLE `myratehistory` (
`consumerId` varchar(255) DEFAULT NULL,
`durationType` varchar(50) DEFAULT NULL,
`itemId` varchar(50) NOT NULL,
`quantity` double DEFAULT NULL,
`quantityType` varchar(100) DEFAULT NULL,
`status` varchar(20) NOT NULL DEFAULT 'CREATED',
`timePeriod` double DEFAULT NULL,
`timestamp` DATETIME NULL,
PRIMARY KEY (`itemId`, `consumerId`, `timestamp`)
) ENGINE=InnoDB AUTO_INCREMENT=314 DEFAULT CHARSET=utf8;
CREATE TRIGGER `newRateToHistory`
AFTER INSERT
ON myrate
FOR EACH ROW
INSERT INTO myratehistory
(
consumerId,
durationType,
itemId,
quantity,
quantityType,
status,
timePeriod,
timestamp
)
VALUES(
new.consumerId,
new.durationType,
new.itemId,
new.quantity,
new.quantityType,
'CREATED',
new.timePeriod,
now());
Note that consumerId CAN be null.
Next I run this SQL statement:
INSERT INTO c_consumption.myrate (
consumerId,
durationType,
itemId,
quantity,
quantityType,
timePeriod)
VALUES(
null,
'DAY',
'MyItem',
1.0,
'GALLON',
1.0);
I get the following message:
Error Code: 1048 Column 'consumerId' cannot be null
Obviously I am doing something wrong but I do not know what it is. Any help would be greatly appreciated.
Thanks!

Answer 1

ConsumerId is part of the primary key. No part of the primary key can be null.

Answer 2

Just a guess, why mysql allows a null-able column as part of the primary key I don't know
CREATE TABLE `myratehistory` (
[...]
PRIMARY KEY (`itemId`, `consumerId`, `timestamp`)

Answer 3

Your MySQL server is running in "strict" mode, which throws an error in case like yours are otherwise handled "gracefully" without strict mode.
As of MySQL 5.7.5, the default SQL mode includes STRICT_TRANS_TABLES, which is exactly the cause of your headache.
To change your server's mode, edit your my.cnf (or my.ini if you're running Windows) and set the mode to:
sql-mode=""
Then you must restart your mysql server like this:
service mysql reload
Or directly throw init.d process:
/etc/init.d/mysql reload
Hope it will help you.