SQL error: #1005 - Can't create table - mysql

Question

Here is my code:
create table if not exists Pelajar (
no_pelajar char(7) not null,
nama varchar(30) not null,
alamat varchar(50) not null,
no_telepon varchar(10),
grade integer not null,
primary key (no_pelajar)
);
create table if not exists Kelas (
kode_kelas char(5) not null,
no_pengajar char(9) not null,
no_pelajaran char(4) not null,
ruang integer not null,
waktu char(5) not null,
primary key (kode_kelas)
);
create table if not exists Pelajaran (
no_pelajaran char(4) not null,
grade integer not null,
subjek varchar(30) not null,
primary key (no_pelajaran)
);
create table if not exists Pengajar (
no_pengajar char(9) not null,
nama varchar(30) not null,
alamat varchar(50) not null,
no_telepon varchar(10) not null,
primary key (no_pengajar)
);
create table if not exists Pembayaran (
no_pembayaran char(11) not null,
status_pembayaran varchar(11) not null,
tgl_pembayaran char(8) not null,
primary key (no_pembayaran)
);
create table if not exists KartuAnggota (
no_pelajar char(7) not null,
kode_kelas char(5) not null
);
create table if not exists SlipPembayaran (
no_pembayaran char(11) not null,
no_pelajar char(7) not null
);
alter table SlipPembayaran
add foreign key (no_pembayaran)
references Pembayaran(no_pembayaran);
alter table SlipPembayaran
add foreign key (no_pelajar)
references Pelajar(no_pelajar);
alter table KartuAnggota
add foreign key (kode_kelas)
references Kelas(kode_kelas);
alter table KartuAnggota
add foreign key (no_pelajar)
references Pelajar(no_pelajar);
alter table Kelas
add foreign key (no_pelajaran)
references Pelajaran(no_pelajaran);
alter table Kelas
add foreign key (no_pengajar)
references Pengajar(no_pengajar);
=================================================================================
after running the code, i got the message:
SQL query:
ALTER TABLE KartuAnggota ADD FOREIGN KEY ( kode_kelas ) REFERENCES Kelas( kode_kelas ) ;
MySQL said:
#1005 - Can't create table 'bimbel.#sql-2f2c_1c6' (errno: 150)
can you explain that?

Answer 1

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 right column names and types, and it must have indexes on the referenced keys, as stated earlier. If these are not satisfied, MySQL returns error number 1005 and refers to error 150 in the error message.