Mysql composite key out of a foreign composite key - mysql

Question

I'm trying to make a many-to-many relationship between two tables In Mysql WorkBench, and one of those 2 tables has a composite primary key ( parts are coming from 2 foreign keys). When I'm trying to generate the SQL I'm getting this error :
ERROR: Error 1215: Cannot add foreign key constraint
SQL Code:
-- -----------------------------------------------------
-- Table `A_D_schema`.`Resources_has_OwnerGroups`
-- -----------------------------------------------------
CREATE TABLE IF NOT EXISTS `A_D_schema`.`Resources_has_OwnerGroups` (
`Resources_id` INT NOT NULL,
`OwnerGroups_id` INT NOT NULL,
`OwnerGroups_Instances_has_Customers_Instances_idInstances` INT NOT NULL,
`OwnerGroups_Instances_has_Customers_Customers_idCustomers` INT NOT NULL,
PRIMARY KEY (`Resources_id`, `OwnerGroups_id`, `OwnerGroups_Instances_has_Customers_Instances_idInstances`, `OwnerGroups_Instances_has_Customers_Customers_idCustomers`),
INDEX `fk_Resources_has_OwnerGroups_OwnerGroups1_idx` (`OwnerGroups_id` ASC, `OwnerGroups_Instances_has_Customers_Instances_idInstances` ASC, `OwnerGroups_Instances_has_Customers_Customers_idCustomers` ASC),
INDEX `fk_Resources_has_OwnerGroups_Resources1_idx` (`Resources_id` ASC),
CONSTRAINT `fk_Resources_has_OwnerGroups_Resources1`
FOREIGN KEY (`Resources_id`)
REFERENCES `A_D_schema`.`Resources` (`id`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_Resources_has_OwnerGroups_OwnerGroups1`
FOREIGN KEY (`OwnerGroups_id` , `OwnerGroups_Instances_has_Customers_Instances_idInstances` , `OwnerGroups_Instances_has_Customers_Customers_idCustomers`)
REFERENCES `A_D_schema`.`OwnerGroups` (`id` , `Instances_has_Customers_Instances_idInstances` , `Instances_has_Customers_Customers_idCustomers`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
From the SHOW ENGINE INNODB STATUS I can see this message :
Cannot resolve column name close to:
)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_Resources_has_OwnerGroups_OwnerGroups1`
FOREIGN KEY (`OwnerGroups_id` , `OwnerGroups_Instances_has_Customers_Instances_idInstances` , `OwnerGroups_Instances_has_Customers_Customers_idCustomers`)
REFERENCES `A_D_schema`.`OwnerGroups` (`id` , `Instances_has_Customers_Instances_idInstances` , `Instances_has_Customers_Customers_idCustomers`)
ON DELETE NO ACTION
ON UPDATE NO ACTION)
ENGINE = InnoDB
The SHOW CREATE TABLE Resources and SHOW CREATE TABLE OwnerGroups :
CREATE TABLE `Resources` (
`idResources` int(11) NOT NULL AUTO_INCREMENT,
`email` varchar(45) DEFAULT NULL,
`role` int(11) DEFAULT NULL COMMENT 'role : 1 disptcher \n0 admin',
PRIMARY KEY (`idResources`),
UNIQUE KEY `idresources_UNIQUE` (`idResources`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;
CREATE TABLE `OwnerGroups` (
`idOwnerGroups` int(11) NOT NULL AUTO_INCREMENT,
`name` varchar(45) DEFAULT NULL,
`group` int(11) DEFAULT NULL,
PRIMARY KEY (`idOwnerGroups`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Answer 1

CONSTRAINT `fk_Resources_has_OwnerGroups_Resources1`
FOREIGN KEY (`Resources_id`)
REFERENCES `A_D_schema`.`Resources` (`id`)
Your Resources table doesn't have a column id. Its primary key is idResources.
CONSTRAINT `fk_Resources_has_OwnerGroups_OwnerGroups1`
FOREIGN KEY (`OwnerGroups_id` , `OwnerGroups_Instances_has_Customers_Instances_idInstances` , `OwnerGroups_Instances_has_Customers_Customers_idCustomers`)
REFERENCES `A_D_schema`.`OwnerGroups` (`id` , `Instances_has_Customers_Instances_idInstances` , `Instances_has_Customers_Customers_idCustomers`)
Your OwnerGroups table doesn't have a column id. Its primary key is idOwnerGroups. It doesn't have the other two columns you reference at all.
In general, when you declare a foreign key, first you name the columns in the child table:
CREATE TABLE Child (
childCol1 INT,
childCol2 INT,
...
FOREIGN KEY (childCol1, childCol2) ...
Then you reference columns in the parent table:
... REFERENCES Parent (parentCol1, parentCol2)
);
You must use the names of columns as they exist in the parent table.
The columns you reference in the parent table must together be the PRIMARY KEY or UNIQUE KEY of that table. In other words, given the example above, it would not work against this Parent table:
CREATE TABLE Parent (
parentCol1 INT,
parentCol2 INT,
PRIMARY KEY (parentCol1)
);
Because the PRIMARY KEY does not include parentCol2.
In your case, the following should work:
CREATE TABLE IF NOT EXISTS `A_D_schema`.`Resources_has_OwnerGroups` (
`Resources_id` INT NOT NULL,
`OwnerGroups_id` INT NOT NULL,
`OwnerGroups_Instances_has_Customers_Instances_idInstances` INT NOT NULL,
`OwnerGroups_Instances_has_Customers_Customers_idCustomers` INT NOT NULL,
PRIMARY KEY (`Resources_id`, `OwnerGroups_id`, `OwnerGroups_Instances_has_Customers_Instances_idInstances`, `OwnerGroups_Instances_has_Customers_Customers_idCustomers`),
CONSTRAINT `fk_Resources_has_OwnerGroups_Resources1`
FOREIGN KEY (`Resources_id`)
REFERENCES `A_D_schema`.`Resources` (`idResources`)
ON DELETE NO ACTION
ON UPDATE NO ACTION,
CONSTRAINT `fk_Resources_has_OwnerGroups_OwnerGroups1`
FOREIGN KEY (`OwnerGroups_id`)
REFERENCES `A_D_schema`.`OwnerGroups` (`idOwnerGroups`)
ON DELETE NO ACTION
ON UPDATE NO ACTION
) ENGINE = InnoDB
I took out a couple of INDEX definitions that are redundant. You don't need to index your PRIMARY KEY, it's already the clustered index of the table. You don't need to index the column you use in a foreign key declaration, MySQL will index that column automatically if it need to (though if an index already exists for that column, the FK constraint will use that index).
I'm not sure I understand what your other two columns OwnerGroups_Instances_has_Customers_Instances_idInstances and OwnerGroups_Instances_has_Customers_Customers_idCustomers are meant to do. Typically in a many-to-many table, you only need enough columns to reference the primary keys of the respective parent tables.
Re your comment:
You should try refreshing the view of the schema from time to time. There's a button with a pair of curvy arrows, to the right of "SCHEMAS".