I'm receiving this error when trying to create a table and I don't know why:
[2016-07-05 14:08:02] [42000][2270] ORA-02270: no matching unique or primary key for this column-list
This question seems different (to me) from a similar question, because in that question the OP is referencing a table with a composite PK, while I am not.
And while this other question has the same error code, it is because the OP is incorrectly references the primary key, which I don't think I did.
May someone more experienced in SQL educate me?
(A couple of things to note: 1) I know the table/column names have small errors/deviations from convention, but this is for homework, and the teacher requires I have the tables and rows declared exactly his way, even if it's non-conventional. 2) Yes, that's silly; but no, I can't change it or I get marked down.)
CREATE TABLE Student_Course
(
Stu_ID NUMBER(5) NOT NULL,
Course_ID VARCHAR2(8) NOT NULL,
Section# NUMBER(3),
CONSTRAINT pk_stu_crse PRIMARY KEY (Stu_ID, Course_ID),
CONSTRAINT fk_course_id FOREIGN KEY (Course_ID) REFERENCES course(Course_ID),
CONSTRAINT fk_stu_id FOREIGN KEY (Stu_ID) REFERENCES student(Stu_ID),
CONSTRAINT fk_section FOREIGN KEY (Section#) REFERENCES course(Section#)
)
There are only two, small, referenced tables, which are:
CREATE TABLE student
(
Stu_ID NUMBER(5) PRIMARY KEY ,
Lname VARCHAR2(20),
Fname VARCHAR2(20),
Mi CHAR(1),
Sex CHAR(1),
Major VARCHAR2(15),
Home_State CHAR(2)
);
CREATE TABLE course
(
Course_ID VARCHAR2(8) PRIMARY KEY ,
Section# NUMBER(3),
C_Name VARCHAR2(30),
C_Description VARCHAR2(30)
);
A foreign key is a reference to a primary key in another table.
The last constraint CONSTRAINT fk_section FOREIGN KEY (Section#) REFERENCES course(Section#) won't work - Section# isn't a primary key in that table
Section# Must be at least UNIQUE in course table.
If you want to use Section# as a reference for a foreign key, it must be a UNIQUE or a PRIMARY KEY
More information about FOREIGN KEY and constraints
Thanks to good answers, I'm posting my code which I corrected based on help here. Hope my corrections help others in the future.
CREATE TABLE student
(
Stu_ID NUMBER(5) PRIMARY KEY ,
Lname VARCHAR2(20),
Fname VARCHAR2(20),
Mi CHAR(1),
Sex CHAR(1),
Major VARCHAR2(15),
Home_State CHAR(2)
);
CREATE TABLE course
(
Course_ID VARCHAR2(8) ,
Section# NUMBER(3) ,
C_Name VARCHAR2(30),
C_Description VARCHAR2(30),
CONSTRAINT pk_course PRIMARY KEY (Course_ID, Section#)
);
CREATE TABLE Student_Course
(
Stu_ID NUMBER(5) ,
Course_ID VARCHAR2(8) ,
Section# NUMBER(3) ,
CONSTRAINT pk_stu_crse PRIMARY KEY (Stu_ID, Course_ID, Section#),
CONSTRAINT fk_stu FOREIGN KEY (Stu_ID) REFERENCES student(Stu_ID),
CONSTRAINT fk_course_id FOREIGN KEY (Course_ID, Section#) REFERENCES course(Course_ID, Section#)
);
Related
I addressed in class that the 2 foreign keys in the FlightData table are Depart_Code and Ariv_Code that there isn't any table to make references to them being a primary key in, in the relational schema we were given.
In class I was told that they reference Airport_Code in the Airport table. I was wondering I would go about doing that? I feel like I am missing something obvious. I appreciate any help offered I am still new to database in general and I am currently on Oracle 11g.
Airport table
CREATE TABLE Airport
(
Airport_Code VARCHAR2(7) CONSTRAINT pk_Airport Primary Key,
City_Code VARCHAR2(3),
CONSTRAINT fk_Airport_City_Code
FOREIGN KEY(City_Code) REFERENCES City,
Airport_Name VARCHAR2(30)
);
FlightData table:
CREATE TABLE FlightData
(
Flt_Nbr VARCHAR2(3) CONSTRAINT pk_FlightData Primary Key,
Depart_Code VARCHAR2(30),
Ariv_Code VARCHAR2(30)
);
To make sure Depart_Code and Ariv_Code always reference an airport in the Airport table you need to:
Make these columns NOT NULL.
Ensure they have the same data type as the key in Airport. Make them have a length of 7.
Add two foreign key constraints, each one based on each column.
For example, the second table could look like:
CREATE TABLE FlightData (
Flt_Nbr VARCHAR2(3) CONSTRAINT pk_FlightData Primary Key,
Depart_Code VARCHAR2(7) not null,
constraint fk1 foreign key (Depart_Code) references Airport (Airport_Code),
Ariv_Code VARCHAR2(7) not null,
constraint fk2 foreign key (Ariv_Code) references Airport (Airport_Code)
);
I'm getting an error from oracle that says "number of referencing columns must match referenced columns."
I want my column recorded_on in the table measurement to reference recorded_on in the table called sample
The column Recorded on in the Sample table must be part of a composite key together with Scientist_Num
The error is coming from
FOREIGN KEY (Recorded_On) REFERENCES Sample(Scientist, Recorded_On, Site_ID)
CREATE TABLE Sample (
Scientist_Num varchar2(5) not null,
Recorded_On date not null,
Site_ID varchar2(4) not null,
Comments clob,
Primary key (Scientist_Num, Recorded_On),
FOREIGN KEY (Scientist_Num) REFERENCES Scientist(Scientist_Num),
FOREIGN KEY (Site_ID) REFERENCES Site(Site_ID)
);
CREATE TABLE Measurement (
Site_ID varchar2(4) not null,
Recorded_On date not null,
Name varchar2(10) not null,
Value varchar2(10),
Outlier_Indicator varchar2(10),
Primary key (Site_ID, Recorded_On, Name),
FOREIGN KEY (Site_ID) REFERENCES Sample(Site_ID),
FOREIGN KEY (Recorded_On) REFERENCES Sample(Scientist, Recorded_On, Site_ID)
);
The Scientist_Num and Recorded_On columns must be in a composite key together.
The answer to my problem and an explanation of what went wrong would be greatly appreciated.
You can create virtual column in sample table:
Recorded_virtual varchar2(5) [GENERATED ALWAYS] AS
(Scientist||Recorded_On||Site_ID) [VIRTUAL]
And create reference to this column:
CONSTRAINT fk_column
FOREIGN KEY (Recorded_On)
REFERENCES Sample(Recorded_virtual )
Foreign key references need to match the primary keys in number and type. So I think you intend:
CREATE TABLE Measurement (
Site_ID varchar2(4) not null,
Scientist_Num varchar2(5) not null,
----^ added for foreign key reference
Recorded_On date not null,
Name varchar2(10) not null,
Value varchar2(10),
Outlier_Indicator varchar2(10),
Primary key (Site_ID, Recorded_On, Name),
FOREIGN KEY (Site_ID) REFERENCES Site(Site_ID),
-------------------------------------^ Presumably you intend the site table
FOREIGN KEY (Scientist_Num, Recorded_On) REFERENCES
Sample(Scientist_Num, Recorded_On)
-----------------^ two columns, both need to already be defined
);
I suspect there are other issues with your data model, but this should fix the syntax error. If you want further help, then ask another question.
i'm creating a few tables which look like this
CREATE TABLE sickness
(
sickness_id number(2),
sickness_name varchar2(20),
PRIMARY KEY (sickness_id)
);
CREATE TABLE cover
(
cover_needed char(1) NOT NULL,
employee_id number(3),
responsibilities varchar2(50),
notes varchar2(50),
PRIMARY KEY (cover_needed, employee_id)
);
this works fine then when i try to make a parent table (see below), i get the error.
ORA-02270: no matching unique or primary key for this column-list
i have however narrowed it down to the last line but i can not for the life of me figure it out, thank you
CREATE TABLE absences
(
absences_id number(2) NOT NULL,
manager_id number(3),
employee_id number(3) NOT NULL,
absence_name varchar2(15) NOT NULL,
sickness_id number(2),
date_from date NOT NULL,
date_to date NOT NULL,
length number(2) NOT NULL,
description varchar2(40),
authorised_by_manager char(1) NOT NULL,
cover_needed char(1) NOT NULL,
half_day char(1) NOT NULL,
PRIMARY KEY (absences_id, manager_id, employee_id),
FOREIGN KEY (sickness_id) REFERENCES sickness (sickness_id),
FOREIGN KEY (cover_needed) REFERENCES cover (cover_needed)
);
This is how you define cover:
CREATE TABLE cover (
. . .
**PRIMARY KEY (cover_needed, employee_id)**
);
You have a composite primary key. Foreign key references need to reference both keys . . . and in the same order.
So:
FOREIGN KEY (cover_needed, employee_id)
REFERENCES cover (cover_needed, employee_id)
I think your data structures and queries would be simpler if you used auto-generated numeric primary keys. That would simplify the foreign key relationships and simplify the queries that connect tables.
Yeah, not too sure on this one. New to sql and I thought everything was done right, any ideas? If this is not the way to add foreign keys, could someone please explain to me how the correct way to do it is please? Would appreciate it, thanks.
CREATE TABLE customer (
reference NUMBER(5) PRIMARY KEY,
company_name VARCHAR2(30),
address VARCHAR2(30),
post_code VARCHAR2(10),
telephone VARCHAR(20),
contact_fname VARCHAR2(20),
contact_sname VARCHAR2(20),
contact_email VARCHAR2(30)
);
CREATE TABLE manifest (
barcode NUMBER(10) PRIMARY KEY,
trip_id NUMBER(10),
pickup_customer_ref VARCHAR2(30),
delivery_customer_ref VARCHAR2(30),
category NUMBER(1),
weight NUMBER(10)
);
CREATE TABLE category (
category NUMBER(1) PRIMARY KEY,
description VARCHAR2(15),
requirements VARCHAR2(30),
FOREIGN KEY (category) REFERENCES manifest(category)
);
CREATE TABLE trip (
trip_id NUMBER(10) PRIMARY KEY,
departure_date DATE,
return_date DATE,
vehicle_id VARCHAR2(10),
employee_no NUMBER(10),
FOREIGN KEY (trip_id) REFERENCES manifest(trip_id)
);
CREATE TABLE vehicle (
registration VARCHAR2(10) PRIMARY KEY,
vehicle_type_id VARCHAR2(10),
model VARCHAR2(15),
make VARCHAR2(15),
body VARCHAR2(15),
year NUMBER(4),
FOREIGN KEY (registration) REFERENCES trip(registration)
);
CREATE TABLE model (
vehicle_type_id VARCHAR(10) PRIMARY KEY,
make VARCHAR2(15),
model VARCHAR2(15),
FOREIGN KEY (vehicle_type_id) REFERENCES vehicle(vehicle_type_id)
);
CREATE TABLE driver (
employee_no NUMBER(10) PRIMARY KEY,
first_name VARCHAR2(20),
last_name VARCHAR(20),
ni_no VARCHAR2(15),
telephone VARCHAR2(20),
mobile VARCHAR2(12),
hazardous_goods VARCHAR2(1),
FOREIGN KEY (employee_no) REFERENCES trip(employee_no)
);
and the error message I get is
SQL Error: ORA-02270: no matching unique or primary key for this column-list
02270. 00000 - "no matching unique or primary key for this column-list"
*Cause: A REFERENCES clause in a CREATE/ALTER TABLE statement
gives a column-list for which there is no matching unique or primary
key constraint in the referenced table.
*Action: Find the correct column names using the ALL_CONS_COLUMNS
catalog view
I get this error for every table after manifest btw
The error message is pretty clear. The reference for a foreign key needs to be a unique or primary key in the other table. So this is wrong in the category table.
FOREIGN KEY (category) REFERENCES manifest(category)
I assume you intend for the manifest to look like this:
CREATE TABLE manifest (
barcode NUMBER(10) PRIMARY KEY,
trip_id NUMBER(10) REFERENCES trip(trip_id),
pickup_customer_ref VARCHAR2(30),
delivery_customer_ref VARCHAR2(30),
category NUMBER(1) REFERENCES category(category),
weight NUMBER(10)
);
And so on for the other places where foreign keys are used. (This uses a short-hand notation for the foreign key reference; a separate clause in CREATE TABLE is also fine.)
Of course, the definition of manifest has to go after category and trip, in this example.
In other words, the reference goes in the other table, not where the primary key is defined.
Also, I would recommend being consistent with the names of the foreign keys. At the very least, they should generally have the same name as the primary key, where possible.
trip_id, vehicle_type_id, and employee_no all need to be marked as UNIQUE.
Having trouble with a ORA-02270 error. After going through the primary keys and foreign keys over and over, I can't find what the problem is.
CREATE TABLE CUSTACC(
REFNO CHAR(4),
ACCNO NUMBER(7),
CONSTRAINT CUSTACC_PK PRIMARY KEY (REFNO, ACCNO));
CREATE TABLE CUST(
CUSTNO CHAR(4),
NAME VARCHAR2(30),
ADDRESS VARCHAR2(50),
AREA VARCHAR2(10),
CONSTRAINT CUSTNO_PK PRIMARY KEY(CUSTNO),
CONSTRAINT CUSTNO_FK FOREIGN KEY (CUSTNO)
REFERENCES CUSTACC(REFNO));
CREATE TABLE ACC(
ACCNO NUMBER(7),
BALANCE NUMBER(8,2),
BRANCH VARCHAR2(10),
OPENED DATE,
BONUS NUMBER(8,2),
CONSTRAINT ACCNO_PK PRIMARY KEY (ACCNO),
CONSTRAINT ACCNO_FK FOREIGN KEY (ACCNO)
REFERENCES CUSTACC(ACCNO));
I must be blind but I've checked everything people have suggested before.
The primary key on CUSTACC consists of two columns: REFNO and ACCNO.
The foreign key reference should include both of them. So, your tables need both columns.
I suspect, in fact, that you want the foreign key reference in the first table, something like this:
CREATE TABLE CUST (
CUSTNO CHAR(4),
NAME VARCHAR2(30),
ADDRESS VARCHAR2(50),
AREA VARCHAR2(10),
CONSTRAINT CUSTNO_PK PRIMARY KEY(CUSTNO)
);
CREATE TABLE ACC (
ACCNO NUMBER(7),
BALANCE NUMBER(8,2),
BRANCH VARCHAR2(10),
OPENED DATE,
BONUS NUMBER(8,2),
CONSTRAINT ACCNO_PK PRIMARY KEY (ACCNO)
);
CREATE TABLE CUSTACC (
REFNO CHAR(4),
ACCNO NUMBER(7),
CONSTRAINT CUSTACC_PK PRIMARY KEY (REFNO, ACCNO),
CONSTRAINT CUSTNO_FK FOREIGN KEY (REFNO)
REFERENCES CUST(CUSTNO),
CONSTRAINT ACCNO_FK FOREIGN KEY (ACCNO)
REFERENCES ACC(ACCNO)
);
Here is a SQL Fiddle.