title: MySQL Foreign Key Error 1005 errno 150 primary key as foreign key
body: <p>I'm making a small DataBase with MySQL Workbench. I have a main table, called &quot;Immobili&quot;, which has a Primary Key composed by four columns: (Comune, Via, Civico, Immobile).</p>
  <p>I also have three other tables, which have the same primary key (Comune, Via, Civico, Immobile), but these fields are also referenced to the table Immobili.</p>
  <p>First question: Can I make a Primary Key that is also a Foreign Key?</p>
  <p>Second Question: When I try to export the changes it says:</p>
  <pre><code>Executing SQL script in server
  
  # ERROR: Error 1005: Can't create table 'dbimmobili.condoni' (errno: 150)
  
  CREATE  TABLE IF NOT EXISTS `dbimmobili`.`Condoni` (
  
    `ComuneImmobile` VARCHAR(50) NOT NULL ,
    `ViaImmobile` VARCHAR(50) NOT NULL ,
    `CivicoImmobile` VARCHAR(5) NOT NULL ,
    `InternoImmobile` VARCHAR(3) NOT NULL ,
    `ProtocolloNumero` VARCHAR(15) NULL ,
    `DataRichiestaSanatoria` DATE NULL ,
    `DataSanatoria` DATE NULL ,
    `SullePartiEsclusive` TINYINT(1) NULL ,
    `SullePartiComuni` TINYINT(1) NULL ,
    `OblazioneInEuro` DOUBLE NULL ,
    `TecnicoOblazione` VARCHAR(45) NULL ,
    `TelefonoTecnico` VARCHAR(15) NULL ,
    INDEX `ComuneImmobile` (`ComuneImmobile` ASC) ,
    INDEX `ViaImmobile` (`ViaImmobile` ASC) ,
    INDEX `CivicoImmobile` (`CivicoImmobile` ASC) ,
    INDEX `InternoImmobile` (`InternoImmobile` ASC) ,
  
    PRIMARY KEY (`ComuneImmobile`, `ViaImmobile`, `CivicoImmobile`, `InternoImmobile`) ,
  
    CONSTRAINT `ComuneImmobile`
      FOREIGN KEY (`ComuneImmobile` )
      REFERENCES `dbimmobili`.`Immobile` (`ComuneImmobile` )
      ON DELETE CASCADE
      ON UPDATE CASCADE,
  
    CONSTRAINT `ViaImmobile`
      FOREIGN KEY (`ViaImmobile` )
      REFERENCES `dbimmobili`.`Immobile` (`ViaImmobile` )
      ON DELETE CASCADE
      ON UPDATE CASCADE,
  
    CONSTRAINT `CivicoImmobile`
      FOREIGN KEY (`CivicoImmobile` )
      REFERENCES `dbimmobili`.`Immobile` (`CivicoImmobile` )
      ON DELETE CASCADE
      ON UPDATE CASCADE,
  
    CONSTRAINT `InternoImmobile`
      FOREIGN KEY (`InternoImmobile` )
      REFERENCES `dbimmobili`.`Immobile` (`InternoImmobile` )
      ON DELETE CASCADE
      ON UPDATE CASCADE
  ) ENGINE = InnoDB
  </code></pre>
  <p>Showing the Engine Status:</p>
  <blockquote>
  <p>Error in foreign key constraint of table dbimmobili/valutazionimercato:</p>
  </blockquote>
  <blockquote>
  <p>Cannot find an index in the referenced table where the referenced columns appear as the first columns, or columns typse in the table and the referenced table do not match for constraint. Note that the internal storage type of ENUM and SET changed in tables created with &gt;= InnoDB-4.1.12, and such columns in old tables cannot be referenced by such columns in new tables.</p>
  </blockquote>
  <p>Where am I doing wrong?</p>