Question

I have a question about how to update a field on cascade with a second field as constraint.

The structure is this (I removed the unnecessary columns):

Table nodes with columns idNode and idDimension (together they form the primary key).

Table forces with columns idForce (PK), idNode (foreign key to nodes.idNode) and idDimension.

Cascade update and delete on everything.

The problem in this structure that it seems to appear is this:

If in nodes I have an entry like (1, 1) and one like (1, 2) and in forces (1, 1, 1) and (1, 1, 2) and I update or delete first entry from nodes both entries in forces will be affected.

I need to affect only the one that also has the corresponding idDimension. How can I modify current structure to do that?

Edit: Tables – Nodes:

CREATE TABLE IF NOT EXISTS `nodes` (
  `idNode` varchar(11) NOT NULL,
  `idDimension` int(10) unsigned NOT NULL,
  `idNetwork` int(10) unsigned NOT NULL DEFAULT '0',
  `level` int(11) unsigned NOT NULL DEFAULT '0',
  `energy` bigint(20) DEFAULT NULL,
  `resources` bigint(20) unsigned NOT NULL DEFAULT '0',
  `x` int(11) NOT NULL,
  `y` int(11) NOT NULL,
  `name` varchar(20) DEFAULT NULL,
  `order` tinyint(3) DEFAULT '0' COMMENT 'energy 0\nassemble 1\nupgrade 2',
  `core` tinyint(1) unsigned NOT NULL DEFAULT '0',
  PRIMARY KEY (`idNode`,`idDimension`),
  KEY `network_dimension` (`idDimension`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1 COMMENT='Node table';

Forces:

 CREATE TABLE IF NOT EXISTS `forces` (
  `idForce` bigint(10) unsigned NOT NULL AUTO_INCREMENT,
  `idNode` varchar(11) NOT NULL,
  `idDimension` int(10) unsigned NOT NULL,
  `drones` bigint(20) DEFAULT NULL,
  `stance` tinyint(3) DEFAULT NULL COMMENT '0 - defense\n1 - neutral\n2 - attack      \n\nIf planet is parano and you are not allied to owner you can only be in attack.\n\nIf owner is allied you can only be in defense or neutral.\n\nIf you are owner you can only be in defense.',
   `order` tinyint(3) DEFAULT '0' COMMENT 'extract energy 1\nbuild node 2\nreplicate 3\nmove 4',
  `value` text,
   PRIMARY KEY (`idForce`),
   KEY `idNode` (`idNode`,`idDimension`),
   KEY `idDimension` (`idDimension`)
  ) ENGINE=InnoDB  DEFAULT CHARSET=latin1 AUTO_INCREMENT=4 ;

—

— Constraints for table forces

  ALTER TABLE `forces`
    ADD CONSTRAINT `forces_ibfk_2` FOREIGN KEY (`idDimension`) REFERENCES `nodes`  (`idDimension`) ON DELETE CASCADE ON UPDATE CASCADE,
    ADD CONSTRAINT `fk_forces_nodes1` FOREIGN KEY (`idNode`, `idDimension`) REFERENCES `nodes` (`idNode`, `idDimension`) ON DELETE NO ACTION ON UPDATE NO ACTION,
    ADD CONSTRAINT `forces_ibfk_1` FOREIGN KEY (`idNode`) REFERENCES `nodes` (`idNode`) ON DELETE CASCADE ON UPDATE CASCADE;

My constraints are not working as I would like so feel free to ignore them :).

Answer 1

There are two strange foreign key (forces_ibfk_1 and forces_ibfk_2) which refers to non unique fields. Remove them –

ALTER TABLE forces DROP FOREIGN KEY forces_ibfk_1;
ALTER TABLE forces DROP FOREIGN KEY forces_ibfk_2;

Then recreate fk_forces_nodes1 that refers to unique pair of fields with CASCADE action option –

ALTER TABLE forces
  DROP FOREIGN KEY fk_forces_nodes1;

ALTER TABLE orces
  ADD CONSTRAINT fk_forces_nodes1 FOREIGN KEY (idNode, idDimension)
    REFERENCES nodes(idNode, idDimension) ON DELETE CASCADE ON UPDATE CASCADE;