I keep getting an error:
There are no primary or candidate keys in the referenced table 'TProducts' that match the referencing column list in the foreign key 'TProducts_TCategories_FK'."
When trying to establish a relationship between my products table and categories table. I have checked the spelling multiple times but can't seem to figure out why I keep getting this error. The rest of my tables are fine, and I used the same method.
CREATE TABLE TCategories
(
intCategoryID INTEGER NOT NULL,
strCategoryName VARCHAR(255) NOT NULL,
CONSTRAINT TCategories_PK PRIMARY KEY (intCategoryID)
)
CREATE TABLE TProducts
(
intProductID INTEGER NOT NULL,
intVendorID INTEGER NOT NULL,
intCategoryID INTEGER NOT NULL,
strProductName VARCHAR(255) NOT NULL,
monCostofProduct MONEY NOT NULL,
monRetailCost MONEY NOT NULL,
intInventory INTEGER NOT NULL,
CONSTRAINT TProducts_PK PRIMARY KEY (intProductID)
)
ALTER TABLE TProducts
ADD CONSTRAINT TProducts_TCategories_FK
FOREIGN KEY (intCategoryID) REFERENCES TProducts (intCategoryID)
You are referencing to TProducts table and not TCategories table:
ALTER TABLE TProducts ADD CONSTRAINT TProducts_TCategories_FK
FOREIGN KEY ( intCategoryID ) REFERENCES TCategories( intCategoryID )
Related
I have two tables:
CREATE TABLE Trasy_srodki_transportu(
ID_Trasy Integer NOT NULL,
ID_pojazdu Integer NOT NULL
)
/
CREATE TABLE Trasy(
ID_Trasy Integer NOT NULL,
Linia Varchar2(4 ) NOT NULL,
Data_rozpoczecia_kursowania Date NOT NULL,
Data_zakonczenia_kursowania Date,
ID_Pracownika Integer NOT NULL
)
Now i want to add foreign key to Trasy_srodki_transportu referencing to Trasy table:
ALTER TABLE Trasy_srodki_transportu ADD CONSTRAINT Trasa_jest_wykorzystywana FOREIGN KEY (ID_Trasy) REFERENCES Trasy (ID_Trasy)
/
and this throws Oracle (ORA-02270) : no matching unique or primary key for this column-list error. Any suggestions how to fix this?Data modeler view
A foreign key needs to reference a key on the related table, but it's not the case in your example. Change the definition of the second table by adding a PRIMARY KEY constraint in it, as in:
CREATE TABLE Trasy (
ID_Trasy Integer PRIMARY KEY NOT NULL,
Linia Varchar2(4 ) NOT NULL,
Data_rozpoczecia_kursowania Date NOT NULL,
Data_zakonczenia_kursowania Date,
ID_Pracownika Integer NOT NULL
)
Alternatively, you can create a unique constraint on it, that can also serve as a key. For example:
CREATE TABLE Trasy (
ID_Trasy Integer NOT NULL,
Linia Varchar2(4 ) NOT NULL,
Data_rozpoczecia_kursowania Date NOT NULL,
Data_zakonczenia_kursowania Date,
ID_Pracownika Integer NOT NULL,
CONSTRAINT uq_idtrasy UNIQUE (ID_Trasy)
)
I know that this question has been already answered a million of times, but I couldn't find any solution. Well I have these three tables on postgres sql.
CREATE TABLE user_account (
id SERIAL not null,
firstName VARCHAR(60) not null,
lastName VARCHAR(60) not null,
password VARCHAR(150) not null,
email VARCHAR(40) not null UNIQUE,
isVolunteer BOOLEAN,
complete BOOLEAN,
CONSTRAINT pk_user PRIMARY KEY (id));
CREATE TABLE incident (
id SERIAL not null,
patientId INTEGER not null,
incidentTime VARCHAR(10) not null,
latitude NUMERIC not null,
longitude NUMERIC not null,
city VARCHAR(60) not null,
state VARCHAR(60),
country VARCHAR(60),
complete BOOLEAN,
CONSTRAINT pk_incident PRIMARY KEY (id, patientId),
CONSTRAINT fk_incident FOREIGN KEY (patientId)
REFERENCES user_account (id) MATCH SIMPLE
ON UPDATE CASCADE ON DELETE CASCADE);
CREATE TABLE incident_has_volunteer (
incidentId INTEGER not null,
volunteerId INTEGER not null,
incidentTime VARCHAR(10) not null,
complete BOOLEAN,
CONSTRAINT pk_incident_has_volunteer PRIMARY KEY (incidentId, volunteerId),
CONSTRAINT fk_volunteer FOREIGN KEY (volunteerId)
REFERENCES user_account (id) MATCH SIMPLE
ON UPDATE CASCADE ON DELETE CASCADE,
CONSTRAINT fk_incident FOREIGN KEY (incidentId)
REFERENCES incident (id) MATCH SIMPLE
ON UPDATE CASCADE ON DELETE CASCADE);
When I try to create the table incident_has_volunteer it throws the error there is no unique constraint matching given keys for referenced table "incident".
I tried to add on the third table and the patientId as a foreign key from table incident table but with no luck. I can't understand why it throws this error even if I have already set the primary keys on the incident table.
I'm not an expert in postgres, but I believe that the problem is while fk_incident is referencing incident.id, incident's primary key is made of id + patientId. Since incident.id is guaranteed to be unique only in combination with patientId, there's no way to ensure referential integrity.
I believe that if you add a unique constraint to incident.id (I'm assuming that it would be unique), your foreign key will be legal.
Very simply - one table of primary key acts as a foreign key for another table, so you must ensure that both key is referenced or not.
Simply you will not assign foreign key to the column of another table which does not have primary key. this is called as RDBMS.
Thanks
I am starting to build something like system up to the just cooperate with suggestions coming into the database called ForslagOpslag.
Every time I try to update table with likes, you will see it with this one error:
Update cannot proceed due to validation errors. Please correct the following errors and try again.
SQL71516 :: The referenced table '[dbo].[ForslagOpslag]' contains no
primary or candidate keys that match the referencing column list in
the foreign key. If the referenced column is a computed column, it
should be persisted.
Here is how I built my ForslagOpslagLikes table:
CREATE TABLE [dbo].[ForslagOpslagLikes]
(
[fk_brugerid] INT NOT NULL,
[opretdato] DATETIME NOT NULL,
[getid] INT NOT NULL,
CONSTRAINT [PK_ForslagOpslagLikes]
PRIMARY KEY CLUSTERED ([fk_brugerid], [getid]),
CONSTRAINT [FK_ForslagOpslagLikes_ToGetid]
FOREIGN KEY ([getid])
REFERENCES [dbo].[ForslagOpslag]([Id]),
CONSTRAINT [FK_ForslagOpslagLikes_ToForslagBrugerid]
FOREIGN KEY ([fk_brugerid])
REFERENCES [dbo].[ForslagOpslag]([fk_brugerid])
);
Reason I have both fk_brugerid and getid is for sure me that the user can not vote / like more once!
The way I have built my ForslagOpslag table:
CREATE TABLE [dbo].[ForslagOpslag]
(
[Id] INT IDENTITY (1, 1) NOT NULL,
[text] NVARCHAR (MAX) NOT NULL,
[fk_brugerid] INT NOT NULL,
[opretdato] DATETIME NOT NULL,
PRIMARY KEY CLUSTERED ([Id] ASC)
);
like this to be my like system do:
ForslagOpslagLikes -> fk_brugerid to ForslagOpslag -> fk_brugerid
ForslagOpslagLikes -> getid to ForslagOpslag -> id
Well - the error seems pretty clear: you're trying to estabslish a foreign key relationship to ForslagOpslag.fk_brugerid here:
CONSTRAINT [FK_ForslagOpslagLikes_ToForslagBrugerid]
FOREIGN KEY ([fk_brugerid])
REFERENCES [dbo].[ForslagOpslag]([fk_brugerid])
but that column is NOT the primary key of that other table - and it's not a UNIQUE constraint either - so you cannot reference that column in a foreign key relationship.
But the column(s) that a foreign key references must be the primary key of that other table - or in SQL Server, it's good enough if there's a UNIQUE constraint on that column. You must ensure that the values you reference in FroslagOpslag only match a single column in that table - otherwise, you cannot establish a foreign key relationship
Try to remove the foreing key in your first table like this
CREATE TABLE [dbo].[ForslagOpslagLikes]
(
[fk_brugerid] INT NOT NULL,
[opretdato] DATETIME NOT NULL,
[getid] INT NOT NULL,
CONSTRAINT [PK_ForslagOpslagLikes]
PRIMARY KEY CLUSTERED ([fk_brugerid], [getid]),
CONSTRAINT [FK_ForslagOpslagLikes_ToGetid]
FOREIGN KEY ([getid])
REFERENCES [dbo].[ForslagOpslag]([Id]),
);
Then you need to add the foreign key in the second table with the primary key with the first table
CREATE TABLE [dbo].[ForslagOpslag]
(
[Id] INT IDENTITY (1, 1) NOT NULL,
[text] NVARCHAR (MAX) NOT NULL,
[fk_brugerid] INT NOT NULL,
[opretdato] DATETIME NOT NULL,
PRIMARY KEY CLUSTERED ([Id] ASC),
CONSTRAINT [FK_ForslagOpslagLikes_ToForslagBrugerid]
FOREIGN KEY ([fk_brugerid])
REFERENCES [dbo].[ForslagOpslagLikes]([fk_brugerid])
);
You sound scandinavian, and Bruger means User (for all the non-scandinavians here).
What you appear to want is a Bruger (User) table, where fk_brugerid in ForslagOpslag is the user who created the record with opretdato being the creation date, and ForslagOpslagLikes is an association table of users who likes the ForslagOpslag with opretdato being the date they clicked on "Like".
CREATE TABLE [dbo].[Bruger]
(
[brugerid] INT IDENTITY (1, 1) NOT NULL,
...,
CONSTRAINT [PK_Bruger]
PRIMARY KEY CLUSTERED ([brugerid])
);
CREATE TABLE [dbo].[ForslagOpslag]
(
[Id] INT IDENTITY (1, 1) NOT NULL,
[text] NVARCHAR(MAX) NOT NULL,
[fk_brugerid] INT NOT NULL,
[opretdato] DATETIME NOT NULL,
CONSTRAINT [PK_ForslagOpslag]
PRIMARY KEY CLUSTERED ([Id]),
CONSTRAINT [FK_ForslagOpslag_Bruger]
FOREIGN KEY ([fk_brugerid])
REFERENCES [dbo].[Bruger] ([brugerid])
);
CREATE TABLE [dbo].[ForslagOpslagLikes]
(
[fk_brugerid] INT NOT NULL,
[opretdato] DATETIME NOT NULL,
[getid] INT NOT NULL,
CONSTRAINT [PK_ForslagOpslagLikes]
PRIMARY KEY CLUSTERED ([fk_brugerid], [getid]),
CONSTRAINT [FK_ForslagOpslagLikes_Bruger]
FOREIGN KEY ([fk_brugerid])
REFERENCES [dbo].[Bruger] ([brugerid]),
CONSTRAINT [FK_ForslagOpslagLikes_ForslagOpslag]
FOREIGN KEY ([getid])
REFERENCES [dbo].[ForslagOpslag]([Id])
);
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 am creating 6 tables. When creating the first 3 tables, everything works well. But then when I have to use a Foreign Key that I have used previously when creating another table, the system presents an error.
These are the 3 first tables:
CREATE TABLE Employee (
EmployeeID INTEGER PRIMARY KEY NOT NULL,
Name TEXT NOT NULL,
Position TEXT NOT NULL,
Salary REAL NOT NULL,
Remarks TEXT
);
CREATE TABLE Planet (
PlanetID INTEGER PRIMARY KEY NOT NULL,
Name TEXT NOT NULL,
Coordinates REAL NOT NULL
);
CREATE TABLE Has_Clearance (
Employee INTEGER NOT NULL
CONSTRAINT fk_Employee_EmployeeID REFERENCES Employee(EmployeeID),
Planet INTEGER NOT NULL
CONSTRAINT fk_Planet_PlanetID REFERENCES Planet(PlanetID),
Level INTEGER NOT NULL,
PRIMARY KEY(Employee, Planet)
);
Then I create the 4th table:
CREATE TABLE Shipment (
ShipmentID INTEGER PRIMARY KEY NOT NULL,
Date TEXT,
Manager INTEGER NOT NULL
CONSTRAINT fk_Employee_EmployeeID REFERENCES Employee(EmployeeID),
Planet INTEGER NOT NULL
CONSTRAINT fk_Planet_PlanetID REFERENCES Planet(PlanetID)
);
And I get the following error:
"There is already an object named 'fk_Employee_EmployeeID' in the database. Could not create constraint."
Please let me know how to create the FK in this 4th table.
The constraint "fk_Employee_EmployeeID" is first created on table "Has_Clearance" and then you try to create another constraint with the same name - which is not allowed.
Just rename the constraint in the 4-th table like this:
CREATE TABLE Shipment (
ShipmentID INTEGER PRIMARY KEY NOT NULL,
Date TEXT,
Manager INTEGER NOT NULL CONSTRAINT fk_Maneger_EmployeeID REFERENCES Employee(EmployeeID),
Planet INTEGER NOT NULL CONSTRAINT fk_Planet_PlanetID REFERENCES Planet(PlanetID)
);