I have a custom table created which has a foreign constraint on the core_website table. However, the on delete cascade isn't working.
I did a search and found this relevant thread, which notes that the data types between the two columns have to be the same. Both data types are smallint(5).
I did notice one minor discrepancy in the column definition, which is that in core_website, Allow Null is not set, and Default is not set to zero, whereas in the account table, Allow Null is set and Default is zero. I didn't think changing these would have any effect, but I went ahead and changed them on the account table to match, but that didn't help.
CREATE TABLE `account` (
`account_id` smallint(11) unsigned NOT NULL AUTO_INCREMENT,
`website_id` smallint(5) unsigned DEFAULT '0',
`code` varchar(64) NOT NULL DEFAULT '',
PRIMARY KEY (`account_id`),
UNIQUE KEY `code` (`code`),
KEY `FK_WEBSITE_ID` (`website_id`),
CONSTRAINT `FK_WEBSITE_ID` FOREIGN KEY (`website_id`) REFERENCES `core_website` (`website_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=44 DEFAULT CHARSET=utf8
try this and let us the result pls.
CREATE TABLE `account` (
`account_id` smallint(11) unsigned NOT NULL AUTO_INCREMENT PRIMARY KEY,
`website_id` smallint(5) unsigned DEFAULT '0',
`code` varchar(64) NOT NULL DEFAULT '',
UNIQUE KEY `code` (`code`),
KEY `FK_WEBSITE_ID` (`website_id`),
CONSTRAINT `FK_WEBSITE_ID` FOREIGN KEY (`website_id`) REFERENCES `core_website` (`website_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=44 DEFAULT CHARSET=utf8
You need add foreign key to core_website table and point it to website_id field in account table. In other words, foreign key should be added to the dependent table and pointed to main table, in this case when you delete row from main table - row from dependent table will be deleted because of FK. In your case you did it "upside down".
Related
Is it possible to cascade delete from same MySQL table? I want to cascade delete in a table that references itself in relations.
Example:
I have a comments table that has comment_id and parent_id, where parent_id is the same id in comment_id.
Parent_id could be either another comment_id or null if it's a root
comment.
I want to be able to select any node in this tree and delete it. In the process, all child nodes and sub-child nodes should be deleted.
I have tried to alter my table using this query
ALTER TABLE `comment`
ADD FOREIGN KEY (`comment_id`)
REFERENCES `comment`(`parent_id`) ON DELETE CASCADE ON UPDATE RESTRICT;
but I end up with an error
Cannot add or update a child row: a foreign key constraint fails
(zendaya001.#sql-6c1_1044ab, CONSTRAINT comment_ibfk_3 FOREIGN
KEY (comment_id) REFERENCES comment (parent_id) ON DELETE
CASCADE ON UPDATE RESTRICT)
For reproduction, this is my comment table:
CREATE TABLE `comment` (
`comment_id` int NOT NULL,
`post_id` int UNSIGNED NOT NULL,
`user_id` int NOT NULL,
`parent_id` int DEFAULT NULL,
`content` text NOT NULL,
`type` varchar(50) DEFAULT NULL,
`count_replies` int NOT NULL DEFAULT '0',
`count_likes` int NOT NULL DEFAULT '0',
`timestamp` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
--
-- Indexes for table `comment`
--
ALTER TABLE `comment`
ADD PRIMARY KEY (`comment_id`),
ADD KEY `user_id` (`user_id`),
ADD KEY `post_id` (`post_id`),
ADD KEY `parent_id` (`parent_id`);
You try to create the foreign key with incorrect direction.
Must be:
ALTER TABLE `comment`
ADD FOREIGN KEY (`parent_id`)
REFERENCES `comment`(`comment_id`) ON DELETE CASCADE ON UPDATE RESTRICT;
https://dbfiddle.uk/iJRlziwL
comment_id must be defined at least UNIQUE (maybe PRIMARY KEY).
I cannot insert a new record into the table even if ON UPDATE RESTRICT is also set to CASCADE – Freesoul
You do something wrongly.
https://dbfiddle.uk/rcUupB2b
CREATE TABLE `class` (
`class_id` int(11) NOT NULL AUTO_INCREMENT,
`section_name` varchar(50) NOT NULL,
`class_alias` varchar(200) NOT NULL,
`grading_scheme` int(11) NOT NULL DEFAULT '0',
`year` year(4) NOT NULL,
`grade_calc_method_id` varchar(20) DEFAULT NULL,
PRIMARY KEY (`class_id`)
) ENGINE=InnoDB AUTO_INCREMENT=48819 DEFAULT CHARSET=latin1;
CREATE TABLE `teachers` (
`teacher_id` int(11) NOT NULL AUTO_INCREMENT,
`user_id` int(11) NOT NULL,
`teacher_subject` varchar(20) NOT NULL DEFAULT 'None',
PRIMARY KEY (`teacher_id`),
KEY `user_id` (`user_id`,`school_id`)
) ENGINE=InnoDB AUTO_INCREMENT=48606 DEFAULT CHARSET=latin1;
CREATE TABLE `teacher_classes` (
`teacher_class_id` int(11) NOT NULL AUTO_INCREMENT,
`teacher_id` int(11) NOT NULL,
`class_id` int(11) NOT NULL,
PRIMARY KEY (`teacher_class_id`),
UNIQUE KEY `teacher_id_class_id` (`teacher_id`,`class_id`),
KEY `teacher_id` (`teacher_id`,`class_id`)
) ENGINE=InnoDB AUTO_INCREMENT=46707 DEFAULT CHARSET=latin1;
Trying to insure data consistency between the tables by using foreign key so that the DBMS can check for errors.I have another junction table teacher_classes
Here is my query to add foreign keys constraint
ALTER TABLE teacher_classes
ADD CONSTRAINT `tc_fk_class_id` FOREIGN KEY (`class_id`)
REFERENCES class (`class_id`) ON UPDATE NO ACTION ON DELETE NO ACTION,
ADD CONSTRAINT `tc_fk_teacher_id` FOREIGN KEY (`teacher_id`)
REFERENCES teachers (`teacher_id`) ON UPDATE NO ACTION ON DELETE NO ACTION;
've seen the other posts on this topic, but no luck, getting following error.
Cannot add or update a child row: a foreign key constraint fails
(DB_NAME.#sql-403_12, CONSTRAINT
tc_fk_teacher_id FOREIGN KEY (teacher_id) REFERENCES teachers
(teacher_id) ON DELETE NO ACTION ON UPDATE NO ACTION)
Too late to Answer. I just had the same problem the solution is easy.
You're getting this error because you're trying to or UPDATE a row to teacher_classes doesn't match the id in table teachers.
A simple solution is disable foreign key checks before performing any operation on the table.
SET FOREIGN_KEY_CHECKS = 0;
After you are done with the table enable it again.
SET FOREIGN_KEY_CHECKS = 1;
Or you can remove not null constraint and insert a NULL value in it.
That's most probably the column definition doesn't match properly. For table teachers the PK column definition is as below.
`teacher_id` int(11) NOT NULL AUTO_INCREMENT
Make sure you have the same definition in your child table teacher_classes
I have 2 tables following below:
CREATE TABLE `queststatus` (
`queststatusid` int(10) unsigned NOT NULL AUTO_INCREMENT,
`characterid` int(11) NOT NULL DEFAULT '0',
`quest` int(6) NOT NULL DEFAULT '0',
`status` tinyint(4) NOT NULL DEFAULT '0',
`time` int(11) NOT NULL DEFAULT '0',
`forfeited` int(11) NOT NULL DEFAULT '0',
`customData` varchar(255) DEFAULT NULL,
PRIMARY KEY (`queststatusid`),
KEY `characterid` (`characterid`),
CONSTRAINT `queststatus_ibfk_1` FOREIGN KEY (`characterid`) REFERENCES `characters` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=2148654268 DEFAULT CHARSET=utf8 ROW_FORMAT=FIXED
and
CREATE TABLE `queststatusmobs` (
`queststatusmobid` int(10) unsigned NOT NULL AUTO_INCREMENT,
`queststatusid` int(10) unsigned NOT NULL DEFAULT '0',
`mob` int(11) NOT NULL DEFAULT '0',
`count` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`queststatusmobid`),
KEY `queststatusid` (`queststatusid`),
CONSTRAINT `queststatusmobs_ibfk_1` FOREIGN KEY (`queststatusid`) REFERENCES `queststatus` (`queststatusid`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 ROW_FORMAT=DYNAMIC;
So,when I update the queststatusid of table queststatus, I use these command because the queststatusid reached the maximum of INT:
SET foreign_key_checks = 1;
SET #newid=0;
UPDATE queststatus SET queststatusid=(#newid:=#newid+1) ORDER BY queststatusid;
this command should makes queststatusid of table queststatusmobs change when queststatusid of of table queststatus update, but it doesn't.
It shows:
ERROR 1452 (23000): Cannot add or update a child row: a foreign key constraint fails (`twms`.`queststatus`, CONSTRAINT `queststatus_ibfk_1` FOREIGN KEY (`characterid`) REFERENCES `characters` (`id`) ON DELETE CASCADE ON UPDATE CASCADE)
I have deleted all useless foreign key which not in queststatus by using this command first:
DELETE FROM queststatusmobs WHERE queststatusid not in (SELECT queststatusid FROM queststatus);
How can I solve this problem?
You didn't have that particular id is not available on your characters table.
First you insert characters table id and used that id as a foreign key on queststatus table.
Or
Remove the foreign key reference from queststatus.
You might not able to change the id if you have a foreign key against it as it validate vice versa. You will either have to disable the foreign key checks or consider about changing the data type to BIGINT. That will be the most appropriate thing instead of trying to modifying the data.
To disable the foreign key check:
SET foreign_key_checks = 0;
Or else you can drop and create the foreign key
I'm building a table with a two part foreign key that references a two part key in another table. It isn't working, and I can't see why because the data types line up.
Can't create table 'tsugi.video_comments' (errno: 150)
Here's the code I'm trying to run:
CREATE TABLE `video_comments` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`video_id` varchar(11) NOT NULL DEFAULT '',
`link_id` int(11) NOT NULL,
`videoTime` int(11) NOT NULL,
`comment` text NOT NULL,
`parent` int(11) unsigned DEFAULT NULL,
`private` tinyint(1) DEFAULT NULL,
`replies` int(11) unsigned DEFAULT '0',
`reports` int(11) DEFAULT '0',
`user_id` int(11) NOT NULL,
`displayname` varchar(2048) DEFAULT NULL,
PRIMARY KEY (`id`),
KEY `video_ibfk_1` (`link_id`),
KEY `video_ibfk_2` (`user_id`),
CONSTRAINT `video_comments_ibfk_1` FOREIGN KEY (`parent`) REFERENCES `video_comments` (`id`) ON DELETE CASCADE,
CONSTRAINT `video_ibfk_1` FOREIGN KEY (`link_id`) REFERENCES `lti_link` (`link_id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `video_ibfk_2` FOREIGN KEY (`user_id`) REFERENCES `lti_user` (`user_id`) ON DELETE CASCADE ON UPDATE CASCADE,
CONSTRAINT `video_key` FOREIGN KEY (`link_id`, `video_id`) REFERENCES `video_ids` (`link_id`, `video_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=285 DEFAULT CHARSET=utf8;
The command runs successfully if I delete the last constraint, so that's where the problem is, not in the other constraints.
Here's the table it's referencing:
CREATE TABLE `video_ids` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`video_id` varchar(11) NOT NULL DEFAULT '',
`link_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `video_key` (`video_id`,`id`),
KEY `link_id` (`link_id`),
KEY `id` (`id`,`video_id`),
CONSTRAINT `video_ids_ibfk_1` FOREIGN KEY (`link_id`) REFERENCES `t_lti_link` (`link_id`) ON DELETE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
To make sure that the video_id and link_id fields are exactly the same, I copied them directly from the existing table's code to the code for creating the new table. I expected that to solve it, but it did not. Here's the error log:
------------------------
LATEST FOREIGN KEY ERROR
------------------------
141114 22:04:09 Error in foreign key constraint of table tsugi/video_comments:
FOREIGN KEY (`link_id`, `video_id`) REFERENCES `video_ids` (`link_id`, `video_id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=285 DEFAULT CHARSET=utf8:
Cannot find an index in the referenced table where the
referenced columns appear as the first columns, or column types
in the table and the referenced table do not match for constraint.
Note that the internal storage type of ENUM and SET changed in
tables created with >= InnoDB-4.1.12, and such columns in old tables
cannot be referenced by such columns in new tables.
See http://dev.mysql.com/doc/refman/5.5/en/innodb-foreign-key-constraints.html
for correct foreign key definition.
Foreign key references need to be to unique or primary keys. So, you can fix this just by having a unique declaration in video_ids:
CREATE TABLE `video_ids` (
`id` int(11) unsigned NOT NULL AUTO_INCREMENT,
`video_id` varchar(11) NOT NULL DEFAULT '',
`link_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
UNIQUE KEY `video_key` (`video_id`,`id`),
KEY `link_id` (`link_id`),
KEY `id` (`id`,`video_id`),
UNIQUE (link_id, video_id),
CONSTRAINT `video_ids_ibfk_1` FOREIGN KEY (`link_id`) REFERENCES `t_lti_link` (`link_id`) ON DELETE CASCADE
) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
Here is a SQL Fiddle with an example.
I've created table Address with this SQL query:
CREATE TABLE `address` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`Street` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
`Number` smallint(6) DEFAULT NULL,
`other_id` bigint(20) NOT NULL,
PRIMARY KEY (`id`),
FOREIGN KEY (`other_id`) REFERENCES `other` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci;
But there's also this query:
CREATE TABLE `address` (
`id` bigint(20) NOT NULL AUTO_INCREMENT,
`Street` varchar(255) COLLATE utf8_unicode_ci DEFAULT NULL,
`Number` smallint(6) DEFAULT NULL,
`other_id` bigint(20) NOT NULL,
PRIMARY KEY (`id`),
KEY `other_id` (`other_id`),
CONSTRAINT `adress_ibfk_1` FOREIGN KEY (`other_id`) REFERENCES `other` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci$$
and it seems that booth query create identical tables.
So can anyone explain to me what does this line do:
KEY `other_id` (`other_id`),
and what is the difference between these two lines:
FOREIGN KEY (`other_id`) REFERENCES `other` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
and
CONSTRAINT `adress_ibfk_1` FOREIGN KEY (`other_id`) REFERENCES `other` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
If the difference between last two lines is that latter gives name 'adress_ibfk_1' to foreign key ? If that's true - should I do it ? I mean, why should I name foreign keys ? Will I ever need their names ?
Thanks ! :)
MySQL interprets KEY as an index, so the second query creates an index on the column other_id.
The difference between the two FK declaration is that you manually set the name in the second line. In the first line, MySQL automatically sets a name.
They do need names, but you don't necessarily have to be aware of them. Some more advanced RDBMS use them to be more explicit when a query raises an error.
KEY is a synonym for INDEX, so that is creating an index on the other_id column.
The only difference in the foreign key construction is that the latter constraint version allows you to name the constraint, whereas the former will be given a system generated name.
This name can be seen in the INFORMATION_SCHEMA TABLE_CONSTRAINTS table.