"Foreign key constraint is incorrectly formed" Trying to make a old project work - mysql

Question

So i'm trying to make a old project work again but when i put back my tables to the new database i'm having this issue
ERROR 1005 (HY000) at line 777: Can't create table ****.#sql-3f2_45 (errno: 150 "Foreign key constraint is incorrectly formed")
There is the table that causing problems:
CREATE TABLE `install__dashboards` (
`id` int(11) NOT NULL PRIMARY KEY,
`zone` varchar(255) CHARACTER SET utf8 DEFAULT NULL,
`protocol` varchar(255) CHARACTER SET utf8 DEFAULT NULL,
`agent` varchar(255) CHARACTER SET utf8 DEFAULT NULL,
`object` varchar(255) CHARACTER SET utf8 DEFAULT NULL,
`type` set('dashboard','visualization','search') DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
--
-- Contraintes pour la table `install__dashboards`
--
ALTER TABLE `install__dashboards`
ADD CONSTRAINT `dash_agent` FOREIGN KEY (`agent`) REFERENCES `install__agents` (`name`),
ADD CONSTRAINT `dash_proto` FOREIGN KEY (`protocol`) REFERENCES `install__ports` (`protocol`),
ADD CONSTRAINT `dash_zone` FOREIGN KEY (`zone`) REFERENCES `install__zone` (`slug`);
References tables :
CREATE TABLE `install__agents` (
`id` int(11) NOT NULL,
`OS` varchar(255) NOT NULL,
`name` varchar(255) NOT NULL,
`zone` varchar(255) NOT NULL,
`IP` text,
`isLog` tinyint(1) NOT NULL DEFAULT '0'
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `install__ports` (
`id` int(11) NOT NULL,
`numero` int(11) NOT NULL,
`protocol` varchar(255) NOT NULL,
`isUDP` tinyint(1) NOT NULL DEFAULT '0',
`machine` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `install__zone` (
`slug` varchar(255) NOT NULL,
`status` enum('notpresent','installing','installed') NOT NULL,
`options` text,
`IPrange` text,
`IPsystem` text,
`system` varchar(255) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

Answer 1

To be honest, the error message isn't very descriptive :-(
To get more details about the cause of the error, just check InnoDB status:
$ mysql -e"SHOW ENGINE INNODB STATUS\G" | grep -C3 "FOREIGN KEY ERROR"
SEMAPHORES
----------
------------------------
LATEST FOREIGN KEY ERROR
------------------------
2022-12-06 11:08:12 0x7f43a80ba700 Error in foreign key constraint of table `test`.`install__dashboards`:
Alter table `test`.`install__dashboards` with foreign key `dash_proto` constraint failed. There is no index in the referenced table where the referenced columns appear as the first columns.------------
So the problem/reason is There is no index in the referenced table where the referenced columns appear as the first columns

Answer 2

You need to create indexes on the referencing column:
CREATE INDEX `ix_install__agents_name` ON `install__agents` (`name`);
CREATE INDEX `ix_install__ports_protocol` ON `install__ports` (`protocol`);
CREATE INDEX `ix_install__zone_slug` ON `install__zone` (`slug`);
but your schema does not look right. It's better to have the ID of the entity.
Something like this:
CREATE TABLE `install__agents` (
`id` int(11) NOT NULL PRIMARY KEY,
`OS` varchar(255) NOT NULL,
`name` varchar(255) NOT NULL,
`zone` varchar(255) NOT NULL,
`IP` text,
`isLog` tinyint(1) NOT NULL DEFAULT '0'
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `install__ports` (
`id` int(11) NOT NULL PRIMARY KEY,
`numero` int(11) NOT NULL,
`protocol` varchar(255) NOT NULL,
`isUDP` tinyint(1) NOT NULL DEFAULT '0',
`machine` varchar(255) NOT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `install__zone` (
`id` int(11) NOT NULL PRIMARY KEY,
`slug` varchar(255) NOT NULL,
`status` enum('notpresent','installing','installed') NOT NULL,
`options` text,
`IPrange` text,
`IPsystem` text,
`system` varchar(255) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
CREATE TABLE `install__dashboards` (
`id` int(11) NOT NULL PRIMARY KEY,
`zone_id` int(11) DEFAULT NULL,
`protocol_id` int(11) DEFAULT NULL,
`agent_id` int(11)DEFAULT NULL,
`object` varchar(255) CHARACTER SET utf8 DEFAULT NULL,
`type` set('dashboard','visualization','search') DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;
ALTER TABLE `install__dashboards`
ADD CONSTRAINT `dash_agent` FOREIGN KEY (`agent_id`) REFERENCES `install__agents` (`id`),
ADD CONSTRAINT `dash_proto` FOREIGN KEY (`protocol_id`) REFERENCES `install__ports` (`id`),
ADD CONSTRAINT `dash_zone` FOREIGN KEY (`zone_id`) REFERENCES `install__zone` (`id`);