title: Error Code: 1062. Duplicate entry 'PRIMARY'
body: <p>So, my professor gave me tables to insert it in a database but when I execute his code, MySQL is constantly giving the Error Code: 1062.
  Here is the conflict tables and the inserts:</p>
  
  <p><strong>TABLES</strong></p>
  
  <pre><code>CREATE TABLE FABRICANTES(
  COD_FABRICANTE integer NOT NULL,
  NOMBRE         VARCHAR(15), 
  PAIS           VARCHAR(15),
  primary key (cod_fabricante)
  );
  
  CREATE TABLE ARTICULOS(
  ARTICULO       VARCHAR(20)NOT NULL,
  COD_FABRICANTE integer NOT NULL,
  PESO           integer NOT NULL ,
  CATEGORIA      VARCHAR(10) NOT NULL,
  PRECIO_VENTA   integer,
  PRECIO_COSTO   integer,
  EXISTENCIAS    integer,
  primary key (articulo,cod_fabricante),
  foreign key (cod_fabricante) references Fabricantes(cod_fabricante)
  );
  </code></pre>
  
  <p><strong>INSERT INTO:</strong></p>
  
  <pre><code>INSERT INTO FABRICANTES VALUES(10,'CALVO', 'ESPAÑA');
  INSERT INTO FABRICANTES VALUES(15,'LU', 'BELGICA');
  INSERT INTO FABRICANTES VALUES(20,'BARILLA', 'ITALIA');
  INSERT INTO FABRICANTES VALUES(25,'GALLO', 'ESPAÑA');
  INSERT INTO FABRICANTES VALUES(30,'PRESIDENT', 'FRANCIA');
  
  INSERT INTO ARTICULOS VALUES ('Macarrones',20, 1, 'Primera',100,98,120);
  INSERT INTO ARTICULOS VALUES ('Tallarines',20, 2, 'Primera',120,100,100);
  INSERT INTO ARTICULOS VALUES ('Tallarines',20, 1, 'Segunda',99,50,100);
  INSERT INTO ARTICULOS VALUES ('Macarrones',20, 1, 'Tercera',80,50,100);
  INSERT INTO ARTICULOS VALUES ('Atún',10, 3, 'Primera',200,150,220);
  INSERT INTO ARTICULOS VALUES ('Atún',10, 3, 'Segunda',150,100,220);
  INSERT INTO ARTICULOS VALUES ('Atún',10, 3, 'Tercera',100,50,220);
  INSERT INTO ARTICULOS VALUES ('Sardinillas',10, 1,'Primera',250,200,200);
  INSERT INTO ARTICULOS VALUES ('Sardinillas',10, 1,'Segunda',200,160,200);
  INSERT INTO ARTICULOS VALUES ('Sardinillas',10, 1,'Tercera',100,150,220);
  INSERT INTO ARTICULOS VALUES ('Mejillones',10, 1, 'Tercera',90,50,200);
  INSERT INTO ARTICULOS VALUES ('Mejillones',10, 1, 'Primera',200,150,300);
  INSERT INTO ARTICULOS VALUES ('Macarrones',25, 1, 'Primera',90,68,150);
  INSERT INTO ARTICULOS VALUES ('Tallarines',25, 1, 'Primera',100,90,100);
  INSERT INTO ARTICULOS VALUES ('Fideos',25, 1, 'Segunda',75,50,100);
  INSERT INTO ARTICULOS VALUES ('Fideos',25, 1, 'Primera',100,80,100);
  INSERT INTO ARTICULOS VALUES ('Galletas Cuadradas',15, 1, 'Primera',100,80,100);
  INSERT INTO ARTICULOS VALUES ('Galletas Cuadradas',15, 1, 'Segunda',70,50,100);
  INSERT INTO ARTICULOS VALUES ('Galletas Cuadradas',15, 1, 'Tercera',50,40,100);
  INSERT INTO ARTICULOS VALUES ('Barquillos',15, 1, 'Primera',100,80,100);
  INSERT INTO ARTICULOS VALUES ('Barquillos',15, 1, 'Segunda',100,80,100);
  INSERT INTO ARTICULOS VALUES ('Canutillos',15, 2, 'Primera',170,150,110);
  INSERT INTO ARTICULOS VALUES ('Canutillos',15, 2, 'Segunda',120,150,110);
  INSERT INTO ARTICULOS VALUES ('Leche entera',30, 1, 'Primera',110,100,300);
  INSERT INTO ARTICULOS VALUES ('Leche desnat.',30, 1, 'Primera',120,100,300);
  INSERT INTO ARTICULOS VALUES ('Leche semi.',30, 1, 'Primera',130,110,300);
  INSERT INTO ARTICULOS VALUES ('Leche entera',30, 2, 'Primera',210,200,300);
  INSERT INTO ARTICULOS VALUES ('Leche desnat.',30, 2, 'Primera',220,200,300);
  INSERT INTO ARTICULOS VALUES ('Leche semi.',30, 2, 'Primera',230,210,300);
  INSERT INTO ARTICULOS VALUES ('Mantequilla',30, 1, 'Primera',510,400,200);
  INSERT INTO ARTICULOS VALUES ('Mantequilla',30, 1, 'Segunda',450,340,200);
  </code></pre>
  
  <p><strong><em>The ERROR:</em></strong> </p>
  
  <pre><code>Error Code: 1062. Duplicate entry 'Macarrones-20' for key 'PRIMARY'
  </code></pre>
  
  <p>If I delete that row gives me the same error but with 'Tallarines-20'</p>
  
  <p>Sorry if there is any spell mistake. Thanks!</p>