I have to create a table how's structure is
create table reparto
(
numrep integer,
nomespec varchar(20),
nomeosp varchar(20),
cittaosp varchar(25),
primary key (numrep,nomespec,nomeosp,cittaosp),
foreign key(nomeosp,cittaosp) references ospedale(nomeosp,cittaosp),
foreign key nomespec references specializzazione(nomeospe)
);
of course I've already create the tables
create table ospedale
(
nomeosp varchar(20),
cittaosp varchar(25),
numasl integer,
idasp varchar(4),
primary key(nomeosp,cittaosp)
);
and
create table specializzazione
(
nomespe varchar (20) primary key
);
of course it doesn't work and I don't know what to do, can someone tell me how to create several differentsforeign key?
There's a few obvious things we can point out here. The column name given in the foreign key definition:
references specializzazione(nomeospe)
^
Doesn't match the column name in the table definition
... specializzazione ( nomespe ...
^^^^^^^
And the column list for the foreign key should be enclosed in parens
... foreign key (nomespec)
^ ^
You have some literal error and incorect order creating tables please check this:
create table specializzazione
(
nomespe varchar (20) primary key
);
create table ospedale
(
nomeosp varchar(20),
cittaosp varchar(25),
numasl integer,
idasp varchar(4),
primary key(nomeosp,cittaosp)
);
create table reparto
(
numrep integer,
nomespec varchar(20),
nomeosp varchar(20),
cittaosp varchar(25),
primary key (numrep,nomespec,nomeosp,cittaosp),
foreign key(nomeosp,cittaosp) references ospedale(nomeosp,cittaosp),
foreign key (nomespec) references specializzazione(nomespe)
);
Related
I am having a hard time understanding why my code is giving me cannot add foreign key constraint error. I just started coding in MySQL so I am sorry for anything dumb.
drop table if exists COURSE_INSTRUCTORJG;
drop table if exists CLASSJG;
drop table if exists COURSEJG;
drop table if exists INSTRUCTORJG;
create table INSTRUCTORJG(
InstructorID int,
DepartHead int,
primary key(InstructorID)
);
create table COURSEJG(
CourseNo char(10),
ComputerNeeded smallint,
primary key(CourseNo)
);
create table CLASSJG(
Building CHAR(20),
RoomNum smallint,
Maxcap int,
primary key(Building, RoomNum)
);
create table COURSE_INSTRUCTORJG (
COURSEJG_CourseNo CHAR(10),
INSTRUCTORJG_InstructorID INT,
Semester CHAR(20),
Section INT,
CLASSJG_Building char(20),
CLASSJG_RoomNum smallint,
primary key(COURSEJG_CourseNo, INSTRUCTORJG_InstructorID, Semester, Section),
foreign key (COURSEJG_CourseNo) references COURSEJG(CourseNo),
foreign key (INSTRUCTORJG_InstructorID) references INSTRUCTORJG(InstructorID),
foreign key (CLASSJG_Building) references CLASSJG(Building),
foreign key (CLASSJG_RoomNum) references CLASSJG(RoomNum)
);
My error is coming from the line: foreign key (CLASSJG_RoomNum) references CLASSJG(RoomNum).
You can reference primary key, keys or unique comnstrqaint, but in table CLASSJG you have a double primary key, so reference both columns or define another key
create table CLASSJG(
Building CHAR(20),
RoomNum smallint,
Maxcap int,
primary key(Building, RoomNum),
KEY(RoomNum)
);
see sample fiddle
CREATE TABLE Departament
(d_nume varchar(30), d_nr int, manager varchar(30), PRIMARY KEY(d_nr),
FOREIGN KEY (manager) REFERENCES Angajat(nume));
CREATE TABLE Angajat
(nume varchar(30), prenume varchar(30), cnp char(13), d_nr int, PRIMARY KEY(cnp),
FOREIGN KEY(d_nr) REFERENCES Departament(d_nr));
"Cannot add foreign key constraint"
I use this editor online http://sqlfiddle.com/
When two tables reference each other, you can use alter table:
CREATE TABLE Departament (
d_nr int,
d_nume varchar(30),
manager char(13),
PRIMARY KEY (d_nr)
);
CREATE TABLE Angajat (
cnp char(13),
nume varchar(30),
prenume varchar(30),
d_nr int,
PRIMARY KEY(cnp),
FOREIGN KEY(d_nr) REFERENCES Departament(d_nr)
);
ALTER TABLE Departament ADD CONSTRAINT FOREIGN KEY (manager) REFERENCES Angajat(cnp);
Foreign key references should also be to the primary key, which I normally make the first column in a table. Here is a SQL Fiddle.
I am trying to create 5 tables (should not be too hard), but I am having issues assigning the foreign keys. PhpMyAdmin gives me this error:
Can't create table 'databasexx.gave' (errno: 150)
Basically all the tables with no foreign keys are created.
DROP TABLE IF EXISTS oppbygging;
CREATE TABLE oppbygging (
gnr INT,
dnr INT,
ant INT,
CONSTRAINT dnr_grn_pk PRIMARY KEY (gnr, dnr)
) ENGINE=InnoDB;
DROP TABLE IF EXISTS onske;
CREATE TABLE onske (
onr INT,
pnr INT,
gnr INT,
prioriet INT,
ferdig INT,
CONSTRAINT pnr_gnr_pk PRIMARY KEY (pnr, gnr)
) ENGINE=InnoDB;
DROP TABLE IF EXISTS person;
CREATE TABLE person (
pnr INT,
fornavn VARCHAR(64),
etternavn VARCHAR(64),
fdato DATE,
CONSTRAINT pnr_pk PRIMARY KEY (pnr),
CONSTRAINT person_pnr_fk FOREIGN KEY (pnr) REFERENCES onske(pnr)
) ENGINE=InnoDB;
DROP TABLE IF EXISTS gave;
CREATE TABLE gave
(
gnr int,
navn varchar (255) UNIQUE,
prod_tid int NOT NULL,
CONSTRAINT gnr_pk PRIMARY KEY (gnr),
CONSTRAINT gave_gnr_fk FOREIGN KEY (gnr) REFERENCES oppbygging(gnr),
CONSTRAINT gave_gnr_fk FOREIGN KEY (gnr) REFERENCES onske(gnr)
) ENGINE=InnoDB;
DROP TABLE IF EXISTS del;
CREATE TABLE del (
dnr INT,
navn VARCHAR(64),
lager_ant INT NOT NULL,
CONSTRAINT dnr_pk PRIMARY KEY (dnr),
CONSTRAINT del_dnr_fk FOREIGN KEY (dnr) REFERENCES oppbygging(dnr)
) ENGINE=InnoDB;
I am sure that I am making some sort of obvious mistake, but I just cannot figure it out. Any help would be very much appreciated.
Here is the relationship view, ignore the Eiendom table:
TO CREATE ANOTHER TABLE WITH A FOREIGN KEY, THE FOREIGN KEY
SPECIFIED MUST BE THE PRIMARY KEY OF AT LEAST ONE TABLE
THAT HAS ALREADY BEEN CREATED,E.G.
CREATE TABLE 1 WITH THE PRIMARY KEY:
CREATE TABLE PERSONS(
PERSON_ID INT(10),
FNAME VARCHAR(20)NOT NULL,
LNAME VARCHAR(20),
DOB DATETIME,
AMOUNTPAID DECIMAL(15,2),
PRIMARY KEY(PERSON_ID)
);
THEN CREATE TABLE 2 WITH THE FOREIGN KEY:
CREATE TABLE COMMENTS(
COMMENTID INT AUTO_INCREMENT,
COMMENTS VARCHAR(500),
PERSON_ID INT(10),
PRIMARY KEY(COMMENTID),
FOREIGN KEY (PERSON_ID) REFERENCES PERSONS(PERSON_ID)
);
My SQL script works fine, till some point where error 1215 appears. I don't know what is wrong whith the code.
Here's the code:
CREATE DATABASE IF NOT EXISTS ΝΟΣΟΚΟΜΕΙΟ;
CREATE TABLE IF NOT EXISTS ΤΜΗΜΑΤΑ
(ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ INT,
ΟΝΟΜΑΣΙΑ_ΤΜΗΜΑΤΟΣ CHAR,
ΣΥΝΟΛΙΚΟΣ_ΑΡΙΘΜΟΣ_ΚΛΙΝΩΝ INT,
ΔΙΑΘΕΣΙΜΟΣ_ΑΡΙΘΜΟΣ_ΚΛΙΝΩΝ INT,
PRIMARY KEY (ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ));
CREATE TABLE IF NOT EXISTS ΑΣΘΕΝΕΙΣ
(ΚΩΔΙΚΟΣ_ΑΣΘΕΝΗ INT,
ΟΝΟΜΑ_ΑΣΘΕΝΗ VARCHAR (20),
ΕΠΩΝΥΜΟ_ΑΣΘΕΝΗ VARCHAR (20),
ΦΥΛΛΟ VARCHAR (1),
ΗΜ_ΝΙΑ_ΓΕΝΝΗΣΗΣ DATE,
ΔΙΕΥΘΥΝΣΗ_ΑΣΘΕΝΗ CHAR ,
ΤΗΛΕΦΩΝΟ_ΑΣΘΕΝΗ VARCHAR (10),
PRIMARY KEY (ΚΩΔΙΚΟΣ_ΑΣΘΕΝΗ));
CREATE TABLE IF NOT EXISTS ΙΑΤΡΟΙ
(ΚΩΔΙΚΟΣ_ΙΑΤΡΟΥ INT ,
ΟΝΟΜΑ_ΙΑΤΡΟΥ VARCHAR (20),
ΕΠΩΝΥΜΟ_ΙΑΤΡΟΥ VARCHAR (20),
ΕΙΔΙΚΟΤΗΤΑ CHAR,
ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ INT,
ΔΙΕΥΘΥΝΣΗ_ΙΑΤΡΟΥ CHAR,
ΤΗΛΕΦΩΝΟ_ΙΑΤΡΟΥ VARCHAR (10),
PRIMARY KEY (ΚΩΔΙΚΟΣ_ΙΑΤΡΟΥ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ) REFERENCES ΤΜΗΜΑΤΑ(ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ)
);
CREATE TABLE IF NOT EXISTS ΠΕΡΙΣΤΑΤΙΚΑ
(ΚΩΔΙΚΟΣ_ΠΕΡΙΣΤΑΤΙΚΟΥ INT,
ΚΩΔΙΚΟΣ_ΑΣΘΕΝΗ INT,
ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ INT,
ΚΩΔΙΚΟΣ_ΙΑΤΡΟΥ INT,
ΗΜ_ΝΙΑ_ΕΙΣΑΓΩΓΗΣ DATE,
ΗΜ_ΝΙΑ_ΕΞΙΤΗΡΙΟΥ DATE,
ΑΞΙΑ_ΠΕΡΙΣΤΑΤΙΚΟΥ INT,
PRIMARY KEY (ΚΩΔΙΚΟΣ_ΠΕΡΙΣΤΑΤΙΚΟΥ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΑΣΘΕΝΗ) REFERENCES ασθενεισ(ΚΩΔΙΚΟΣ_ΑΣΘΕΝΗ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ) REFERENCES τμηματα(ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΙΑΤΡΟΥ) REFERENCES ιατροι(ΚΩΔΙΚΟΣ_ΙΑΤΡΟΥ)
);
CREATE TABLE IF NOT EXISTS ΚΑΤΗΓΟΡΙΕΣ_ΠΡΟΪΟΝΤΩΝ
(ΚΩΔΙΚΟΣ_ΚΑΤΗΓΟΡΙΑΣ INT,
ΟΝΟΜΑΣΙΑ_ΚΑΤΗΓΟΡΙΑΣ CHAR,
PRIMARY KEY (ΚΩΔΙΚΟΣ_ΚΑΤΗΓΟΡΙΑΣ)
);
CREATE TABLE IF NOT EXISTS ΠΡΟΪΟΝΤΑ
(ΚΩΔΙΚΟΣ_ΠΡΟΪΟΝΤΟΣ INT,
ΚΩΔΙΚΟΣ_ΚΑΤΗΓΟΡΙΑΣ INT,
ΟΝΟΜΑΣΙΑ_ΠΡΟΪΟΝΤΟΣ CHAR,
ΑΞΙΑ_ΜΟΝΑΔΑΣ_ΠΡΟΪΟΝΤΟΣ INT,
PRIMARY KEY (ΚΩΔΙΚΟΣ_ΠΡΟΪΟΝΤΟΣ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΚΑΤΗΓΟΡΙΑΣ) REFERENCES ΚΑΤΗΓΟΡΙΕΣ_ΠΡΟΪΟΝΤΩΝ(ΚΩΔΙΚΟΣ_ΚΑΤΗΓΟΡΙΑΣ)
);
CREATE TABLE IF NOT EXISTS ΧΡΕΩΣΕΙΣ_ΠΕΡΙΣΤΑΤΙΚΩΝ
(ΚΩΔΙΚΟΣ_ΠΕΡΙΣΤΑΤΙΚΟΥ INT,
ΚΩΔΙΚΟΣ_ΠΡΟΪΟΝΤΟΣ INT,
ΗΜΕΡΟΜΗΝΙΑ_ΧΡΕΩΣΗΣ DATE,
ΠΟΣΟΤΗΤΑ INT,
PRIMARY KEY (ΗΜΕΡΟΜΗΝΙΑ_ΧΡΕΩΣΗΣ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΠΕΡΙΣΤΑΤΙΚΟΥ) REFERENCES ΠΕΡΙΣΤΑΤΙΚΑ(ΚΩΔΙΚΟΣ_ΠΕΡΙΣΤΑΤΙΚΟΥ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΠΡΟΪΟΝΤΟΣ) REFERENCES ΠΡΟΙΟΝΤΑ(ΚΩΔΙΚΟΣ_ΠΡΟΪΟΝΤΟΣ)
);
...........................................
I have a problem with the last two tables where that error occurs.Is there anyone that could help me ?
Thanks, Dimitris
I tested this on Linux, MySQL 5.6.17. I was able to get this to work with two changes:
Match the case of table names to the way they are spelled when you create them:
CREATE TABLE IF NOT EXISTS ΠΕΡΙΣΤΑΤΙΚΑ
(
. . .
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΑΣΘΕΝΗ) REFERENCES ΑΣΘΕΝΕΙΣ(ΚΩΔΙΚΟΣ_ΑΣΘΕΝΗ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ) REFERENCES ΤΜΗΜΑΤΑ(ΚΩΔΙΚΟΣ_ΤΜΗΜΑΤΟΣ),
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΙΑΤΡΟΥ) REFERENCES ΙΑΤΡΟΙ(ΚΩΔΙΚΟΣ_ΙΑΤΡΟΥ)
);
Use the same spelling, including diacritics in ΠΡΟΪΟΝΤΑ:
CREATE TABLE IF NOT EXISTS ΧΡΕΩΣΕΙΣ_ΠΕΡΙΣΤΑΤΙΚΩΝ
(
. . .
FOREIGN KEY (ΚΩΔΙΚΟΣ_ΠΡΟΪΟΝΤΟΣ) REFERENCES ΠΡΟΪΟΝΤΑ(ΚΩΔΙΚΟΣ_ΠΡΟΪΟΝΤΟΣ)
);
I am trying to create three tables however I am getting error as
You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'REFERENCES personal_details(personID)
)'
The above error is for third table i.e. table hobbies_person.
I am creating tables as follow.
CREATE TABLE personal_details (
personID INT PRIMARY KEY,
firstName varchar(30),
middleName varchar(30),
lastName varchar(30),
age INT,
aboutMe varchar(500)
);
CREATE TABLE hobbies (
hobbID INT PRIMARY KEY,
hobbName varchar(30)
);
CREATE TABLE hobbies_person (
personID INT,
hobbID INT,
PRIMARY KEY (personID, hobbID),
FOREIGN KEY personID REFERENCES personal_details(personID)
);
I also tried with
CREATE TABLE hobbies_person (
personID INT,
hobbID INT,
PRIMARY KEY (personID, hobbID),
FOREIGN KEY personID REFERENCES personal_details(personID),
FOREIGN KEY hobbID REFERENCES hobbies(hobbID)
);
but still same error.
Link to check query
Any idea how to tackle this?
NOTE
In table hobbies_person I am using composite primary key as PRIMARY KEY (personID, hobbID),
You need to enclose the column personID in brackets for the FK definition:
CREATE TABLE hobbies_person (
personID INT NOT NULL,
hobbID INT NOT NULL,
PRIMARY KEY (personID, hobbID),
FOREIGN KEY (personID) REFERENCES personal_details(personID)
);
You forgot the () around your foreign key
FOREIGN KEY (personID) REFERENCES personal_details(personID)