Sistema de emprestimo (LP3)

Criação das tabelas.sql

CREATE TABLE livro (
  id INT NOT NULL PRIMARY KEY GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
  nome VARCHAR(30)
);

CREATE TABLE amigo (
  id INT NOT NULL PRIMARY KEY GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
  nome VARCHAR(30),
  telefone VARCHAR(9)
);

CREATE TABLE emprestimo (
  id INT NOT NULL PRIMARY KEY GENERATED ALWAYS AS IDENTITY (START WITH 1, INCREMENT BY 1),
  id_livro INT NOT NULL,
  id_amigo INT NOT NULL
);

ALTER TABLE emprestimo ADD FOREIGN KEY (id_livro) REFERENCES livro(id);
ALTER TABLE emprestimo ADD FOREIGN KEY (id_amigo) REFERENCES amigo(id);