All I need is to create 2 tabeles with next structure:
The SQL:
CREATE TABLE IF NOT EXISTS `ds_cats` (
`id` int(11) NOT NULL AUTO_INCREMENT,
PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 AUTO_INCREMENT=1 ;
CREATE TABLE IF NOT EXISTS `module_news_cats` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`parent` int(11) NOT NULL,
`cat_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `fk_module_news_cats_module_news_cats` (`parent`),
KEY `fk_module_news_cats_ds_cats1` (`cat_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
ALTER TABLE `module_news_cats`
ADD CONSTRAINT `fk_module_news_cats_ds_cats1` FOREIGN KEY (`cat_id`) REFERENCES `ds_cats` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION,
ADD CONSTRAINT `fk_module_news_cats_module_news_cats` FOREIGN KEY (`parent`) REFERENCES `module_news_cats` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION;
But when I try to insert first row to my table "module_news_cats", I recive next error:
#1452 - Cannot add or update a child row: a foreign key constraint fails (`empty`.`module_news_cats`, CONSTRAINT `fk_module_news_cats_module_news_cats` FOREIGN KEY (`parent`) REFERENCES `module_news_cats` (`id`) ON DELETE NO ACTION ON UPDATE NO ACTION)
Question:
How I can create table which will have an index with non-identifying relationship to the anther index in the same table? Some rows will have parents, and some not.
I think you just need to allow NULLs in module_news_cats.parent:
CREATE TABLE IF NOT EXISTS `module_news_cats` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`parent` int(11) NULL, -- Change this
`cat_id` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `fk_module_news_cats_module_news_cats` (`parent`),
KEY `fk_module_news_cats_ds_cats1` (`cat_id`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 AUTO_INCREMENT=1 ;
and then if there isn't a parent, create the row with a NULL in parent.
Your 'parent' field cannot be empty (NULL) if you insert a record, which means that every record you insert should refer to a parent ID (which is impossible if there are no entries in your table yet).
If you make the 'parent' field in the module_news_cats table nullable:
ALTER TABLE `module_news_cats` CHANGE `parent` `parent` INT( 11 ) NULL DEFAULT NULL
you should be able to insert records that have no parent ID associated (just supply NULL instead of a value).
You could make the parent column in the module_news_cats table nullable.
Then for rows that have no parents populate the parent column with null.
Related
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
Is it possible (and how can I achieve it) to get some kind of inheritance with database tables?
I intend to have a parent table X
CREATE TABLE `X` (
`xId` int(11) NOT NULL AUTO_INCREMENT,
`addressId` int(11) NOT NULL,
`poiType` enum('ParkingPOI','ChargingPOI') NOT NULL,
`status` enum('AVAILABLE','NOT_AVAILABLE') NOT NULL
PRIMARY KEY (`aId`),
KEY `fk_x_address_idx` (`addressId`),
CONSTRAINT `fk_address` FOREIGN KEY (`addressId`) REFERENCES `addresses` (`addressId`)
ON DELETE NO ACTION ON UPDATE CASCADE) ENGINE=InnoDB AUTO_INCREMENT=217 DEFAULT CHARSET=utf8;
and a child table B
CREATE TABLE `B` (
`bId` int(11) NOT NULL AUTO_INCREMENT,
`xId` int(11) NOT NULL',
`status` enum('AVAILABLE','NOT_AVAILABLE','PARTLY_AVAILABLE') NOT NULL
PRIMARY KEY (`bId`),
KEY `aId` (`xId`),
CONSTRAINT `fk_a` FOREIGN KEY (`xId`) REFERENCES `X` (`xId`) ON DELETE NO ACTION ON UPDATE NO ACTION) ENGINE=InnoDB AUTO_INCREMENT=2 DEFAULT CHARSET=utf8;
In table X I want to have something like an ENUM with values being inherited from the child table, for instance: AVAILABLE, NOT_AVAILABLE. In this table/column of the parent table (X) only these values shall be allowed.
In the child table, however, this ENUM should be extendend so that the values AVAILABE, NOT_AVAILABLE, PARTLY_AVAILABLE shall be possible.
How can I achieve this?
I have a table like so:
CREATE TABLE `jngi_category` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`Name` varchar(50) NOT NULL,
`parent` int(11) NOT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8
and i want, when a parent delete all of it's child delete so.
if there is any relations that defines by foreign-key so it do that automatically is good.
Add a foreign key constraint on this column parent with ON DELETE CASCADE:
CONSTRAINT `FK_ParentCategory` FOREIGN KEY (`parent`)
REFERENCES jngi_category(id) ON DELETE CASCADE ON UPDATE CASCADE
SQL Fiddle Demo
Try this sql
CREATE TABLE jngi_category (
id int(11) NOT NULL auto_increment,
Name varchar(50) NOT NULL,
parent int(11),
PRIMARY KEY (id),
foreign key (parent) references jngi_category(id) on delete cascade
) ENGINE=InnoDB AUTO_INCREMENT=3 DEFAULT CHARSET=utf8 ;
I have a problem with create table statement in MySQL.
The scenario is, I want to have a table P_CDP wchich stores some informations, and the table P_CDPFiles which stores the data of the uploaded files.
The column SelectedCDPFileID by default should be NULL unless the user selects some file. Then that column is filled by the file ID. But, I'm still getting the errno 150, why ? I think the FK names are set properly
CREATE TABLE `P_CDP` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`P_OrderID` int(11) NOT NULL DEFAULT '0',
`SelectedCDPFileID` int(11) NULL,
PRIMARY KEY (`ID`),
KEY `FK_P_CDP_P_Orders` (`P_OrderID`),
KEY `FK_P_CDP_P_CDPFiles` (`SelectedCDPFileID`),
CONSTRAINT `FK_P_CDP_P_Orders` FOREIGN KEY (`P_OrderID`) REFERENCES `P_Orders` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_P_CDP_P_CDPFiles` FOREIGN KEY (`SelectedCDPFileID`) REFERENCES `P_CDPFiles` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
CREATE TABLE `P_CDPFiles` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`FileID` int(11) NOT NULL DEFAULT '0',
`P_CDPID` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`ID`),
KEY `FK_P_CDPFiles_File` (`FileID`),
KEY `FK_P_CDPFiles_P_CDP` (`P_CDPID`),
CONSTRAINT `FK_P_CDPFiles_File` FOREIGN KEY (`FileID`) REFERENCES `File` (`FileID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_P_CDPFiles_P_CDP` FOREIGN KEY (`P_CDPID`) REFERENCES `P_CDP` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
You're attempting to reference a table that does not yet exist.
If you must have references in both directions between these two tables (which generally indicates quite poor design), you will have to:
Create the first table without any reference to the as-yet-undefined table:
CREATE TABLE `P_CDP` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`P_OrderID` int(11) NOT NULL DEFAULT '0',
`SelectedCDPFileID` int(11) NULL,
PRIMARY KEY (`ID`),
KEY `FK_P_CDP_P_Orders` (`P_OrderID`),
KEY `FK_P_CDP_P_CDPFiles` (`SelectedCDPFileID`),
CONSTRAINT `FK_P_CDP_P_Orders` FOREIGN KEY (`P_OrderID`)
REFERENCES `P_Orders` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
Create the second table, including its reference to the first table:
CREATE TABLE `P_CDPFiles` (
`ID` int(11) NOT NULL AUTO_INCREMENT,
`FileID` int(11) NOT NULL DEFAULT '0',
`P_CDPID` int(11) NOT NULL DEFAULT '0',
PRIMARY KEY (`ID`),
KEY `FK_P_CDPFiles_File` (`FileID`),
KEY `FK_P_CDPFiles_P_CDP` (`P_CDPID`),
CONSTRAINT `FK_P_CDPFiles_File` FOREIGN KEY (`FileID`)
REFERENCES `File` (`FileID`) ON DELETE NO ACTION ON UPDATE NO ACTION,
CONSTRAINT `FK_P_CDPFiles_P_CDP` FOREIGN KEY (`P_CDPID`)
REFERENCES `P_CDP` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;
Alter the first table to add the intended constraint:
ALTER TABLE `P_CDP`
ADD CONSTRAINT `FK_P_CDP_P_CDPFiles` FOREIGN KEY (`SelectedCDPFileID`)
REFERENCES `P_CDPFiles` (`ID`) ON DELETE NO ACTION ON UPDATE NO ACTION;
I have this table:
CREATE TABLE IF NOT EXISTS `produtos` (
`id` int(11) NOT NULL auto_increment,
`idcatprodutos` int(11) NOT NULL,
`idcategoria` int(11) NOT NULL,
`idmarca` int(11) NOT NULL,
`nome` varchar(100) NOT NULL,
PRIMARY KEY (`id`),
KEY `FK_produtos_2` (`idcatprodutos`),
KEY `FK_produtos_3` (`idmarca`),
KEY `FK_produtos_4` (`idcategoria`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 ROW_FORMAT=DYNAMIC AUTO_INCREMENT=39 ;
and this table:
CREATE TABLE IF NOT EXISTS `sugestoes` (
`id` int(11) NOT NULL auto_increment,
`idproduto` int(11) NOT NULL,
`idsugestao1` int(11) NOT NULL,
`idsugestao2` int(11) NOT NULL,
`idsugestao3` int(11) NOT NULL,
`idsugestao4` int(11) NOT NULL,
PRIMARY KEY (`id`),
KEY `FK_sugestoes_prod` (`idproduto`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 ROW_FORMAT=FIXED AUTO_INCREMENT=9 ;
I already have created a fk sugestoes.idproduto -> produtos.id working, but I want each of the other fields also refer to the produtos.id through new FK.
Run this command below that return MySQL Error : #1005 - Can't create table (errno: 150):
ALTER TABLE `infantile`.`sugestoes` ADD CONSTRAINT `FK_sugestoes_2` FOREIGN KEY `FK_sugestoes_2` (`idsugestao1`)
REFERENCES `produtos` (`id`)
ON DELETE SET NULL
ON UPDATE CASCADE
, ROW_FORMAT = FIXED;
Does anyone have any idea what's going on?
Try this,
it works:
ALTER TABLE `sugestoes`
ADD CONSTRAINT `FK_idproduto_produtos_1` FOREIGN KEY (`idproduto`) REFERENCES `produtos` (`id`),
ADD CONSTRAINT `FK_sugestoes_produtos_2` FOREIGN KEY (`idsugestao1`) REFERENCES `produtos` (`id`),
ADD CONSTRAINT `FK_sugestoes_produtos_3` FOREIGN KEY (`idsugestao2`) REFERENCES `produtos` (`id`),
ADD CONSTRAINT `FK_sugestoes_produtos_4` FOREIGN KEY (`idsugestao3`) REFERENCES `produtos` (`id`),
ADD CONSTRAINT `FK_sugestoes_produtos_5` FOREIGN KEY (`idsugestao4`) REFERENCES `produtos` (`id`)
UPDATE:
You can not specify
ON DELETE SET NULL
Because of this:
You have defined a SET NULL condition though some of the
columns are defined as NOT NULL
You can see exact error when you run
SHOW ENGINE INNODB STATUS;
Perhaps removing the ROW_FORMAT = FIXED:
ALTER TABLE `infantile`.`sugestoes`
ADD CONSTRAINT `FK_sugestoes_2`
FOREIGN KEY `FK_sugestoes_2` (`idsugestao1`)
REFERENCES `produtos` (`id`)
ON DELETE SET NULL
ON UPDATE CASCADE
;
On second thought, how do you expect the ON DELETE SET NULL to behave when your column is defined with NOT NULL ?
And third, does the table has any data in it? If some of the rows violate this FK constraint, then you can't create that FK.