I'm creating a DBSM on Mysql Workbench, but when Itry creating the last table i get an error because it can't add the foreign key, but i can't understand why since the child key has the same data type and collation as the parent key and the name isn't repeated.
That's the code for the two tables:
CREATE TABLE PRESTITO( MATRICOLA_U INT, CODICE_LIB SMALLINT(4), DATA_P DATE, DATA_R DATE, N_DIP SMALLINT(2), PRIMARY KEY(CODICE_LIB), FOREIGN KEY(MATRICOLA_U) REFERENCES UTENTI(MATRICOLA), FOREIGN KEY(CODICE_LIB) REFERENCES LIBRI(CODICE_L) ); CREATE TABLE DIPARTIMENTO( NUMERO_DIP SMALLINT(2), NOME_DIP VARCHAR(50) NOT NULL, INDIRIZZO_DIP VARCHAR(50), PRIMARY KEY(NUMERO_DIP), FOREIGN KEY (NUMERO_DIP) REFERENCES PRESTITO(N_DIP) );
Is there someone able to help? Thank you very much!