MySQL - Clave foranea en la misma tabla

create table depart (dept_no int,

	primary key(dept_no));

create table emple (emp_no int,

	dir int,

	dept_no int,

	foreign key (dept_no) references depart (dept_no)

	on delete cascade on update cascade,

	primary key(emp_no));

alter table emple add key (dir);

alter table emple add foreign key (dir) references emple (dept_no);

ERROR 1025 (HY000): Error on rename of './empleados/#sql-321_4' to './empleados/emple' (errno: 150 - Foreign key constraint is incorrectly formed)

Welcome to the MariaDB monitor.  Commands end with ; or \g.

Your MariaDB connection id is 85

Server version: 10.0.24-MariaDB mariadb.org binary distribution

Copyright (c) 2000, 2016, Oracle, MariaDB Corporation Ab and others.

Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.

MariaDB [dblaweb]> create table depart (dept_no int,

    ->  primary key(dept_no));

Query OK, 0 rows affected (0.24 sec)

MariaDB [dblaweb]> create table emple (emp_no int,

    ->  dir int,

    ->  dept_no int,

    ->  foreign key (dept_no) references depart (dept_no)

    ->  on delete cascade on update cascade,

    ->  primary key(emp_no));

Query OK, 0 rows affected (0.27 sec)

MariaDB [dblaweb]> alter table emple add key (dir);

Query OK, 0 rows affected (0.16 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [dblaweb]> alter table emple add foreign key (dir) references emple (dept_no);

Query OK, 0 rows affected (0.73 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [dblaweb]>

create database empleados character set utf8 collate utf8_general_ci;

use empleados;

create table depart (dept_no int,

	nombre varchar(50),

	loc varchar(50),

	primary key(dept_no));

create table emple (emp_no int,

	apellido varchar(50),

	oficio varchar(50),

	dir int,

	fecha_alt date,

	salario dec(10,0),

	comision dec(10,0),

	dept_no int,

	foreign key (dept_no) references depart (dept_no)

	on delete cascade on update cascade,

	primary key(emp_no));

insert into depart value ("10","CONTABILIDAD","SERVILLA"),

	("20","INVESTIGACION","MADRID"),

	("30","VENTAS","BARCELONA"),

	("40","PRODUCCION","BILBAO");

insert into emple value ("7369","SANCHEZ","EMPLEADO","7902","1980/12/17","10400",NULL,"20"),

	("7499","ARROYO","EMPLEADO","7698","1980/02/20","2080000","39000","30"),

	("7521","SALA","VENDEDOR","7698","1981/02/22","162500","162500","30"),

	("7566","JIMENEZ","DIRECTOR","7839","1981/04/02","386750",NULL,"20"),

	("7654","MARTIN","VENDEDOR","7698","1981/09/29","182000",NULL,"30"),

	("7698","NEGRO","DIRECTOR","7839","1981/05/01","370500",NULL,"20"),

	("7788","GIL","ANALISTA","7566","1981/11/09","3900000",NULL,"20"),

	("7839","REY","PRESIDENTE",NULL,"1981/11/17","6500000",NULL,"10"),

	("7844","TOVAR","VENDEDOR","7698","1981/09/08","1950000","0","30"),

	("7876","ALONSO","EMPLEADO","7788","1981/09/23","143000",NULL,"20"),

	("7900","JIMENO","EMPLEADO","7698","1981/12/03","12350000",NULL,"30"),

	("7902","FERNANDEZ","ANALISTA","7566","1981/12/03","390000",NULL,"20"),

	("7934","MUÑOZ","EMPLEADO","7782","1982/01/23","169000",NULL,"10");

alter table emple add key (dir);

alter table emple add foreign key (dir) references emple (emp_no) on delete cascade on update cascade;

alter table depart add tlf int;