cant create a MySql table - mysql

Question

I have created this table
CREATE TABLE `Overview` (
`id` int(11) NOT NULL AUTO_INCREMENT,
`ops` varchar(11) NOT NULL,
`date` date NOT NULL,
`title` text,
`beneficiary_Institution` varchar(100) DEFAULT NULL,
`description` longtext,
`public_Expenditure_Budget` decimal(14,2) DEFAULT NULL,
`payments` decimal(14,2) DEFAULT NULL,
`completition_percent` int(11) DEFAULT NULL,
`start` varchar(11) DEFAULT NULL,
`finish` varchar(11) DEFAULT NULL,
`sub_projects` int(11) DEFAULT NULL,
`public_aid` decimal(14,2) DEFAULT NULL,
`operational_programme_number` int(11) DEFAULT NULL,
`operational_programme` varchar(100) DEFAULT NULL,
`title_ops` text,
`map_coordinates` varchar(15000) DEFAULT NULL,
PRIMARY KEY (`id`,`ops`,`date`)
)ENGINE=InnoDB;
and i try to create a table that has a foreign key with that
CREATE TABLE `Proposal_Body` (
`id` INT(11) NOT NULL AUTO_INCREMENT,
`ops` VARCHAR(11) NULL,
`title` VARCHAR(100) NULL,
`representative` VARCHAR(45) NULL,
`address` VARCHAR(45) NULL,
`email` VARCHAR(45) NULL,
PRIMARY KEY (`id`),
INDEX `fk_Proposal_Body_1_idx` (`ops` ASC),
CONSTRAINT `fk_Proposal_Body_1`
FOREIGN KEY (`ops`)
REFERENCES `espanew`.`Overview` (`ops`)
ON DELETE NO ACTION
ON UPDATE NO ACTION
)ENGINE=InnoDB;
This and any other attempt i tried gives me this error
ERROR 1005 (HY000): Can't create table
'Espa_Projects_Eng.Proposal_Body' (errno: 150)
I know that this is a foreign key problem, but i cant see the reason. This code is a comming from the mysql client, where i did the creation using the ui, didnt type the commands by hand, so it should work.
Thanks a lot

Answer 1

Reading from the documentation:
If you re-create a table that was dropped, it must have a definition
that conforms to the foreign key constraints referencing it. It must
have the correct column names and types, and it must have indexes on
the referenced keys, as stated earlier. If these are not satisfied,
MySQL returns Error 1005 and refers to Error 150 in the error message,
which means that a foreign key constraint was not correctly formed.
Similarly, if an ALTER TABLE fails due to Error 150, this means that a
foreign key definition would be incorrectly formed for the altered
table.
As you can see your first table has this primary key:
PRIMARY KEY (`id`,`ops`,`date`)
but in the second table the foreign key is:
FOREIGN KEY (`ops`)
You have to correct this to make it work.

Answer 2

Your Primary key is a composite key
PRIMARY KEY (id,ops,date)
And your foreign key is consist of only single column i.e.
FOREIGN KEY (ops)
Foreign keys have to match the primary/unique key they reference column for column. To remove this error either you need to add id and date to the Proposal_Body table or your first table Overview primary key is wrong and should just be (id).