Sql Fiddle errors - sql

Question

I am trying to create SQL statements for an assignment in SQL Fiddle and I keep getting the error "Cannot add foreign key constraint". I have tried various things but I recieve different errors when I change things. What am I doing wrong?
CREATE TABLE Person (
ID int NOT NULL,
FName varchar(255),
LName varchar(255),
Preferred_Name varchar(255),
PRIMARY KEY (ID)
)
;
CREATE TABLE Song (
ID varchar(255) NOT NULL,
Title varchar(255),
Run_Time varchar(255),
Lyrics varchar(255),
LeadID int,
FOREIGN KEY (LeadID) REFERENCES Person(ID),
PRIMARY KEY (ID)
)
;
CREATE TABLE Album (
Title varchar(255) NOT NULL,
Run_Time int,
Release_Year TIMESTAMP,
PRIMARY KEY (Title)
)
;
CREATE TABLE Has (
Album_Title varchar(255),
Song_Title varchar(255),
FOREIGN KEY (Album_Title) REFERENCES Album(Title),
FOREIGN KEY (Song_Title) REFERENCES Song(ID)
)
;
CREATE TABLE Part_Of (
PersonID int,
SongID int,
Role varchar(255) NOT NULL,
FOREIGN KEY (PersonID) REFERENCES Person(ID),
FOREIGN KEY (SongID) REFERENCES Song(ID),
PRIMARY KEY (Role)
)
;

Answer 1

In the Song and Has tables you defined Song.ID and Has.Song_Title as a varchar(255). In the Part_Of table you defined SongID as an int. This is why the foreign key is failing. Use the same datatype in all tables (INT seems like a good option) to fix this.
CREATE TABLE Song (
ID varchar(255) NOT NULL, <------
Title varchar(255),
Run_Time varchar(255),
Lyrics varchar(255),
LeadID int,
FOREIGN KEY (LeadID) REFERENCES Person(ID),
PRIMARY KEY (ID)
)
;
CREATE TABLE Has (
Album_Title varchar(255),
Song_Title varchar(255), <-----
FOREIGN KEY (Album_Title) REFERENCES Album(Title),
FOREIGN KEY (Song_Title) REFERENCES Song(ID)
)
;
CREATE TABLE Part_Of (
PersonID int,
SongID int, <-----
Role varchar(255) NOT NULL,
FOREIGN KEY (PersonID) REFERENCES Person(ID),
FOREIGN KEY (SongID) REFERENCES Song(ID),
PRIMARY KEY (Role)
)
;