Here's my problem when I write my SQLSever expressions:
There are no primary or candidate keys in the referenced table 'Room'
that match the referencing column list in the foreign key 'FK_Booking_RoomNo__4E298478'.
And some snapshots to my program:
CREATE TABLE Booking(
HotelNo NVARCHAR(4) not null,
GuestNo SMALLINT,
DateFrom DATETIME not null,
DateTo DATETIME,
RoomNo SMALLINT not null,
PRIMARY KEY (HotelNo,DateFrom,RoomNo),
FOREIGN KEY (HotelNo) REFERENCES Hotel(HotelNo),
FOREIGN KEY (GuestNo) REFERENCES Guest(GuestNo),
FOREIGN KEY (RoomNo) REFERENCES Room(RoomNo)); <---trouble on this line
CREATE TABLE Room(
RoomNo SMALLINT not null,
HotelNo NVARCHAR(4) not null,
RoomType NVARCHAR(25),
Price DECIMAL(5,2),
PRIMARY KEY (RoomNo,HotelNo),
CONSTRAINT fk_Room FOREIGN KEY (HotelNo) REFERENCES Hotel(HotelNo));
and here is the Hotel table
CREATE TABLE Hotel(
HotelNo NVARCHAR(4) not null,
HotelName NVARCHAR(25),
City NVARCHAR(25),
PRIMARY KEY (HotelNo) );
I tried to do some search on this problem, and it says this might be caused when there's no primary key defined in the table Room, but as above, it is defined.
Can someone please help me with this problem?
Thank you in advance.
Any reference to composite key must also include both columns.
FOREIGN KEY (RoomNo, HotelNo) REFERENCES Room(RoomNo, HotelNo))
Related
I'm a beginner learning SQL and am having trouble implementing this concept.
Suppose you create the following three tables:
CREATE TABLE dogOwner(
ownerNo VARCHAR(8) CONSTRAINT ownerNo_pk1 PRIMARY KEY,
ownerName VARCHAR(10)
);
CREATE TABLE catOwner(
ownerNo VARCHAR(8) CONSTRAINT ownerNo_pk2 PRIMARY KEY,
ownerName VARCHAR(10)
);
CREATE TABLE petsAdopted(
petNo VARCHAR(8) CONSTRAINT petNo_pk PRIMARY KEY,
ownerNo VARCHAR(8) CONSTRAINT ownerNo_fk1 REFERENCES dogOwner(ownerNo)
CONSTRAINT ownerNo_fk2 REFERENCES catOwner(ownerNo)
);
How do you properly create constraints for the foreign key ownerNo, which references ownerNo from two other tables?
You can't. You could have 2 columns in petsAdopted: dogOwnerNo and catOwnerNo and 2 foreign keys. But the table design doesn't seem to make sense: surely a pet either is a dog or a cat (or something else) regardless of who owns it?
Here is an alternative design:
CREATE TABLE owner(
ownerNo VARCHAR(8) CONSTRAINT ownerNo_pk2 PRIMARY KEY,
ownerName VARCHAR(10)
);
CREATE TABLE petsAdopted(
petNo VARCHAR(8) CONSTRAINT petNo_pk PRIMARY KEY,
petType VARCHAR2(10) NOT NULL CONSTRAINT petTypeChk (CHECK petType in ('CAT','DOG'))
ownerNo VARCHAR(8) CONSTRAINT ownerNo_fk REFERENCES owner(ownerNo)
);
This only address syntax part of your answer which You have got lot of syntax error, but this will not work, Please rethink your design.
CREATE TABLE dogOwner(
ownerNo VARCHAR(8) CONSTRAINT ownerNo_pk1 PRIMARY KEY,
ownerName VARCHAR(10)
);
CREATE TABLE catOwner(
ownerNo VARCHAR(8),
ownerName VARCHAR(10),
CONSTRAINT ownerNo_pk2 PRIMARY KEY (ownerNo),
CONSTRAINT ownerNo_fk1 FOREIGN KEY (ownerNo) REFERENCES dogOwner(ownerNo)
);
CREATE TABLE petsAdopted(
petNo VARCHAR(8) ,
ownerNo VARCHAR(8),
CONSTRAINT petNo_pk PRIMARY KEY (petNo),
CONSTRAINT ownerNo_fk_pet1 FOREIGN KEY (ownerNo) REFERENCES dogOwner(ownerNo),
CONSTRAINT ownerNo_fk_pet2 FOREIGN KEY (ownerNo) REFERENCES catOwner(ownerNo)
);
I did look up for solutions for this problem but i still get the same error..
I'm trying to insert values into PART and MANUFACTURER tables. Initially, i inserted values into MANUFACTURER without knowing the fact i need to deal with the parent table i.e. PART. So, i did the PART then the MANUFACTURER but still not working :(.
These are the tables:
PART(PNum, PName, PUnitPrice, ComponentOf)
primary key (PNum)
foreign key (ComponentOf) references PART(PNum)
MANUFACTURER(MName, MAddress, MPhone)
primary key (MName)
candidate key (MPhone)
candidate key (MAddress)
PART-MANUFACTURED(MDate, PNum, MName, Quantity)
primary key (MName, PNum, MDate)
foreign key (PNum) references PART(PNum)
foreign key (MName) references MANUFACTURER(MName)
CUSTOMER(CNum, CName, CType)
primary key (CNum)
domain constraint ctype in ('INDIVIDUAL', 'INSTITUTION')
ORDERS(CNum, PNum, OrderDate, OrderQuantity)
primary key (CNum, PNum, OrderDate)
foreign key (CNum) references CUSTOMER(CNum)
foreign key (PNum) references PART(PNum)
Create statements:
CREATE TABLE PART(PNum VARCHAR(25) NOT NULL, PName VARCHAR(75) NOT NULL, PUnitPrice NUMBER(7,2) NOT NULL, ComponentOf VARCHAR(25), PRIMARY KEY(PNum), FOREIGN KEY(ComponentOf) REFERENCES PART(PNum));
Table created.
SQL> CREATE TABLE MANUFACTURER(MName VARCHAR(50) NOT NULL, MAddress VARCHAR(100) NOT NULL, MPhone VARCHAR(25) NOT NULL, PRIMARY KEY(MName), CONSTRAINT UK_MADDRESS Unique(MAddress), CONSTRAINT UK_MPHONE UNIQUE(MPhone));
Table created.
SQL> CREATE TABLE PARTMANUFACTURED(MDate DATE NOT NULL, PNum VARCHAR(25) NOT NULL, MName VARCHAR(50) NOT NULL, QUANTITY NUMBER(10) NOT NULL, PRIMARY KEY(MName, PNum, MDate), FOREIGN KEY(PNum) REFERENCES PART(PNum), FOREIGN KEY(MName) REFERENCES MANUFACTURER(MName));
Table created.
SQL> CREATE TABLE CUSTOMER(CNum VARCHAR(25) NOT NULL, CName VARCHAR(75) NOT NULL, CType VARCHAR(20) NOT NULL, PRIMARY KEY(CNum), CHECK(Ctype in('INDIVIDUAL','INSTITUTION')));
Table created.
SQL> CREATE TABLE ORDERS(CNum VARCHAR(25) NOT NULL, PNum VARCHAR(25) NOT NULL, OrderDate DATE NOT NULL, OrderQuantity NUMBER(7,2) NOT NULL, PRIMARY KEY(CNum, PNum, OrderDate), FOREIGN KEY(CNum) REFERENCES CUSTOMER(CNum), FOREIGN KEY(PNum) REFERENCES PART(PNum));
Isn't the PNum already the primary or parent key? and PART table is the parent table? since, other tables have the PNum as foreign key.. i really don't get it..
anyone knows and can help me with it, is greatly appreciated. thanks :)
The error with your insert statement INSERT INTO PART VALUES('S001', 'System-economy', 1100, 'Null') is that you are trying to insert a string 'NULL' rather than an actual NULL for the column ComponentOf in the PART table.
The problem with the string 'NULL' is that you have a FOREIGN KEY constraint on ComponentOf that references the column PNum, which means that all the values in the column ComponentOf must also be in PNum. However, there is no value 'NULL' in PNum so that's why it threw the error. An actual NULL works since it means that it is not referencing anything.
The value inserted for ComponentOf has to match an existing PNum in the PARTS table. Your key is their to ensure you don't have any "orphaned" components.
If you try to insert 'Null' (a string value as mentioned in the comments) then it can't find the "parent". However, null is allowed since it means that particular part is not a component of any other part, i.e. it doesn't have a "parent".
This is my first database, I created HOTEL, ROOM and GUEST tables, but when I execute the BOOKING table, it's not working.
The error is:
There are no primary or candidate keys in the referenced table 'ROOM'
that match the referencing column list in the foreign key
'FK_BOOKING_ROOM'
Scripts:
CREATE DATABASE HOTEL
USE HOTEL
CREATE TABLE HOTEL
(
HolCode varchar(20) UNIQUE NOT NULL,
Name varchar(30),
City varchar(20) DEFAULT 'Ha noi',
CONSTRAINT PK_HOLEL PRIMARY KEY (HolCode)
)
CREATE TABLE ROOM
(
RoomNo int,
HolCode varchar(20),
TypeRoom char(1) DEFAULT 'S',
Price double precision,
CONSTRAINT CHK_TYPE CHECK (TypeRoom = 'D' OR TypeRoom = 'S' OR TypeRoom = 'F'),
CONSTRAINT CHK_PRICE CHECK (10 <= Price AND Price <= 200),
CONSTRAINT PK_ROOM PRIMARY KEY (RoomNo, HolCode),
CONSTRAINT FK_ROOM FOREIGN KEY (HolCode) REFERENCES HOTEL(HolCode)
)
-- TAO BANG GUEST
CREATE TABLE GUEST
(
GuestNo int,
GuestName varchar(30),
Address varchar(50),
CONSTRAINT PK_GUEST PRIMARY KEY (GuestNo)
)
--TAO BANG BOOKING
CREATE TABLE BOOKING
(
HolNo varchar(20) NOT NULL,
GuestNo int NOT NULL,
DateFrom DateTime DEFAULT GETDATE(),
DateTo DateTime,
RoomNo int NOT NULL,
CONSTRAINT PK_BOOKING PRIMARY KEY (HolNo, DateFrom, RoomNo),
-- CONSTRAINT FK_BOOKING_HOTEL FOREIGN KEY (HolNo) REFERENCES HOTEL(Code),
CONSTRAINT FK_BOOKING_GUEST FOREIGN KEY (GuestNo) REFERENCES GUEST(GuestNo),
CONSTRAINT FK_BOOKING_ROOM FOREIGN KEY (RoomNo, HolCode)
REFERENCES ROOM(RoomNo, HolCode)
)
DROP TABLE BOOKING
Try:
CONSTRAINT FK_BOOKING_ROOM FOREIGN KEY (RoomNo,HolNo)
REFERENCES ROOM(RoomNo,HolCode)
Rooms aren't uniquely identified by just a RoomNo so the foreign key needs to have the hotel code also. I'd also suggest, just as a stylistic point, that you try to use the same names in every table where the contents should be the same - so either HolNo or HolCode, but not both.
I'm getting this error when trying to create a table with foreign key:
There are no primary or candidate keys in the referenced table 'TeamToPlayers' that match the referencing column list in the foreign key 'FKey2'.
I don't understand why, there is a primary key in the table TeamToPlayers.
Here are the queries:
create table TeamToPlayers
(TeamName varchar(50) NOT NULL,
PlayerName varchar(50) NOT NULL,
primary key(TeamName,PlayerName),
CONSTRAINT FKey FOREIGN KEY (TeamName) REFERENCES Teams(TeamName)
)
create table Players
(PlayerName varchar(50) NOT NULL,
primary key(PlayerName),
CONSTRAINT FKey2 FOREIGN KEY (PlayerName) REFERENCES TeamToPlayers(PlayerName)
);
Table TeamToPlayers primary key consists of two fields - you must reference both as otherwise it's not a key. I think you may have your key the wrong way round - it should be on TeamToPlayers and referencing Players like so:
create table TeamToPlayers
(
TeamName varchar(50) NOT NULL,
PlayerName varchar(50) NOT NULL,
primary key(TeamName,PlayerName),
CONSTRAINT FKey FOREIGN KEY (TeamName) REFERENCES Teams(TeamName),
CONSTRAINT FKey2 FOREIGN KEY (PlayerName) REFERENCES Players(PlayerName)
)
create table Players
(PlayerName varchar(50) NOT NULL,
primary key(PlayerName),
);
I cant find a good anwser too my question, I want to create a table that have references too one table but i use it twice in the code..
Vårdnadshavare VARCHAR(11),
FOREIGN KEY (Vårdnadshavare) REFERENCES Person(Personnummer),
Barn VARCHAR(11),
FOREIGN KEY (Barn) REFERENCES Person(Personnummer)
But then i get the error:
ORA-02256: number of referencing columns must match referenced columns
I understand that my reference is wrong some how but can´t figure it out...
Sorry for the swedish words!!
Create table Ärende(
Ärendenr VARCHAR(50) NOT NULL,
Handläggare VARCHAR(50),
FOREIGN KEY (Handläggare) REFERENCES Handläggare(Anställningsnr),
Vårdnadshavare VARCHAR(11),
FOREIGN KEY (Vårdnadshavare) REFERENCES Person(Personnummer),
Barn VARCHAR(11),
FOREIGN KEY (Barn) REFERENCES Person(Personnummer),
In Datum VARCHAR(50),
Ömmande Skäl VARCHAR(5),
Förskola VARCHAR(50),
FOREIGN KEY (Förskola) REFERENCES Förskola(IDnr),
PRIMARY KEY (Ärendenr)
);
I have used Person(Personnumer) as a reference before just not twice in createing a table..
I created this script which does work. Probably there is an issue with your indexes:
create table handläggare
( anställningsnr varchar(50) primary key
)
create table person
( personnummer varchar(11) primary key
)
;
create table förskola
( idnr varchar(50) primary key
);
create table ärende
( ärendenr varchar(50) not null
, handläggare varchar(50)
, foreign key (handläggare) references handläggare(anställningsnr)
, vårdnadshavare varchar(11)
, foreign key (vårdnadshavare) references person(personnummer)
, barn varchar(11)
, foreign key (barn) references person(personnummer)
, indatum varchar(50)
, ömmandeskäl varchar(5)
, förskola varchar(50)
, foreign key (förskola) references förskola(idnr)
, primary key (ärendenr)
);
There are two other issues in your script above which I edited:
In Datum should be one name, not separated by a space;
Ömmande Skäl, same as above.
In you create statement you have provided 4 referenes:
Handläggare VARCHAR(50),
FOREIGN KEY (Handläggare) REFERENCES Handläggare(Anställningsnr),
Vårdnadshavare VARCHAR(11),
FOREIGN KEY (Vårdnadshavare) REFERENCES Person(Personnummer),
Barn VARCHAR(11),
FOREIGN KEY (Barn) REFERENCES Person(Personnummer),
Förskola VARCHAR(50),
FOREIGN KEY (Förskola) REFERENCES Förskola(IDnr),
Please check that all 3 distinct columns are of same data type.
That means:
Handläggare(Anställningsnr) should be VARCHAR(50)
Person(Personnummer) should be VARCHAR(11)
Förskola(IDnr) should be VARCHAR(50).
As per me i think you are making a mistake in
Förskola(IDnr) should be VARCHAR(50)
which should have been a Number