create table departamento(
cod_dep char(5) not null constraint cp_dep primary key initially immediate deferrable,
nombre varchar(40) not null,
director varchar(20),
telefono char(15));

create table profesor(
cod_pro char(5) not null constraint cp_prof primary key initially immediate deferrable,
nombre varchar(40) not null,
telefono char(15),
cod_dep char(5) constraint ca_prof_dep references departamento(cod_dep) initially immediate deferrable);

create table asignatura(
cod_asg char(5) not null constraint cp_asi primary key initially immediate deferrable,
nombre varchar(40) not null,
semestre char(2) not null,
teoria number(3,1) not null,
prac number(3,1) not null,
cod_dep char(5) constraint ca_asi_dep references departamento(cod_dep) initially immediate deferrable);

create table docencia(
cod_pro char(5) not null constraint ca_doc_prof references profesor(cod_pro) initially immediate deferrable,
cod_asg char(5) not null constraint ca_doc_asi references asignatura(cod_asg) initially immediate deferrable,
gteo number(2) not null,
gprac number(2) not null,
constraint cp_doc primary key(cod_pro, cod_asg) initially immediate deferrable);