Given this schema:
create table Review2 (
RID varchar(3),
YID varchar(3),
BID varchar(3),
-- other columns
primary key(RID,YID,BID)
);
create table textualContent2(
TID varchar(3),
RID varchar(3) NOT NULL,
-- other columns
primary key (TID),
foreign key (RID) references Review2 on delete cascade
);
I get this error:
ORA-02256: number of referencing columns must match referenced columns
Why is that and how do I fix it?
Review2 has PK:
primary key(RID,YID,BID),
but your FK definition
foreign key (RID) references Review2
uses the shorthand version, which implies referenced columns as being the PK columns (RID,YID,BID), so it's the same as coding:
foreign key (RID) references Review2(RID,YID,BID)
As suggested by the error message:
number of referencing columns must match referenced columns
the number of columns referenced (RID,YID,BID) disagrees those referencing (RID).
To fix the problem, either change your FK to:
foreign key (RID) references Review2(RID)
and define a unique constraint on RID in Review2, or add columns YID and BID to textualContent2 and add them to the FK:
foreign key (RID,YID,BID) references Review2(RID,YID,BID)
Related
This question already has an answer here:
ORA-02256: referencing foreign key
(1 answer)
Closed last year.
CREATE TABLE Goft_ForeEver_cus(
customer_Id VARCHAR(10),
first_Name VARCHAR2(20) CONSTRAINT sys_cus_fName_nn NOT NULL,
last_Name VARCHAR2(20) CONSTRAINT sys_cus_lName_nn NOT NULL,
girt_Card_Amount NUMBER(5,2) CONSTRAINT sys_cus_gca_nn NOT NULL,
email VARCHAR2(30) CONSTRAINT sys_cus_email_ck CHECK (email ='%[^a-z,0-9,#,.,_,-]%' ) CONSTRAINT sys_cus_email_nn NOT NULL,
CONSTRAINT sys_cus_pk PRIMARY KEY(customer_Id)
);
ALTER TABLE Goft_ForeEver_cus
ADD CONSTRAINT sys_cus_email_UK UNIQUE (email);
CREATE TABLE Goft_ForeEver_Course_Info(
course_Name VARCHAR2(20),
city VARCHAR2(30) CONSTRAINT sys_courtInf_city_nn NOT NULL,
prov VARCHAR2(20) CONSTRAINT sys_courtInf_prov_nn NOT NULL,
postal_Code VARCHAR2(10) CONSTRAINT sys_courtInf_posC_nn NOT NULL,
star_rating NUMBER(1,1),
discript VARCHAR2(200) CONSTRAINT sys_courtInf_descript_uk UNIQUE,
year_Build DATE CONSTRAINT sys_courtInf_date_nn NOT NULL,
court_length Number(5,2)
CONSTRAINT sys_courtInf_courtL_ck CHECK( court_length = 'YARD')
CONSTRAINT sys_courtInf_courtL_nn NOT NULL,
CONSTRAINT sys_courtInf_pk PRIMARY KEY (course_Name, star_rating )
);
CREATE TABLE Goft_ForeEver_favorite_courses(
course_Name VARCHAR2(20),
customer_Id VARCHAR2(10),
CONSTRAINT sys_favCourt_PK PRIMARY KEY(course_Name,customer_Id),
CONSTRAINT sys_favCourt_FK1 FOREIGN KEY (customer_Id) REFERENCES Goft_ForeEver_cus(customer_Id),
CONSTRAINT sys_favCourt_FK2 FOREIGN KEY (course_Name) REFERENCES Goft_ForeEver_Course_Info(course_Name)
);
);
Error
Error report - ORA-02256: number of referencing columns must match referenced columns 02256. 00000 - "number of referencing columns must match referenced columns" *Cause: The number of columns in the foreign-key referencing list is not equal to the number of columns in the referenced list. *Action: Make sure that the referencing columns match the referenced columns.
It is because Goft_ForeEver_Course_Info has primary key as
CONSTRAINT sys_courtInf_pk PRIMARY KEY (course_Name, star_rating )
while Goft_ForeEver_favorite_courses that references it has foreign key as
CONSTRAINT sys_favCourt_FK2 FOREIGN KEY (course_Name) REFERENCES Goft_ForeEver_Course_Info(course_Name)
See? You're referencing COURSE_NAME, STAR_RATING composite key by COURSE_NAME only - that won't work.
Therefore, either remove STAR_RATING from the primary key in Goft_ForeEver_Course_Info, add STAR_RATING to Goft_ForeEver_favorite_courses, or redesign everything alltogether.
Illustration (SQL*Plus, which points to the error):
SQL> CREATE TABLE Goft_ForeEver_favorite_courses(
2 course_Name VARCHAR2(20),
3 customer_Id VARCHAR2(10),
4 CONSTRAINT sys_favCourt_PK PRIMARY KEY(course_Name,customer_Id),
5 CONSTRAINT sys_favCourt_FK1 FOREIGN KEY (customer_Id) REFERENCES Goft_ForeEver_cus(customer_Id),
6 CONSTRAINT sys_favCourt_FK2 FOREIGN KEY (course_Name) REFERENCES Goft_ForeEver_Course_Info(course_Name)
7 );
CONSTRAINT sys_favCourt_FK2 FOREIGN KEY (course_Name) REFERENCES Goft_ForeEver_Course_Info(course_Name)
*
ERROR at line 6:
ORA-02270: no matching unique or primary key for this column-list
SQL>
The problem here is you have declared the "course_Name" along with "star_rating" column as composite primary key in Goft_ForeEver_Course_Info table whereas you are referencing only one column "course_Name" in sys_favCourt_FK2 foreign key declaration in Goft_ForeEver_favorite_courses table.
CREATE TABLE Route(
RouteNo VARCHAR(10),
Origin VARCHAR(30),
Destination VARCHAR(30),
DepartureTime VARCHAR(15),
SerialNo VARCHAR(5),
ArrivalTime VARCHAR(15),
PRIMARY KEY(RouteNo) );
CREATE TABLE Employee(
EmployeeID VARCHAR(5) NOT NULL,
Name VARCHAR(30),
Phone NUMBER,
JobTitle VARCHAR(30),
PRIMARY KEY(EmployeeID) );
CREATE TABLE Flight(
SerialNo VARCHAR(5),
RouteNo VARCHAR(5),
FlightDate DATE,
ActualTD VARCHAR(10),
ActualTA VARCHAR(10),
PRIMARY KEY(SerialNo, RouteNo, FlightDate),
FOREIGN KEY(RouteNo) REFERENCES Route(RouteNo),
FOREIGN KEY(SerialNo) REFERENCES Airplane(SerialNo) ); -- does Airplane table exists ?
CREATE TABLE CrewAssigment(
EmployeeID VARCHAR(5),
RouteNo VARCHAR(5),
FlightDate DATE,
Role VARCHAR(45),
Hours INT,
PRIMARY KEY(EmployeeID, RouteNo, FlightDate),
FOREIGN KEY(EmployeeID) REFERENCES Employee(EmployeeID),
FOREIGN KEY(RouteNo) REFERENCES Route(RouteNo),
FOREIGN KEY(FlightDate) REFERENCES Flight(FlightDate) );
Select * from CrewAssignment
This is my code where I'm getting an error in the CrewAssignment table and above are the tables where the foreign key is referenced from.
Error report -
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
A few objections.
This is clearly an Oracle question, not MySQL. How do I know? ORA-02270 is an Oracle database error code; pay attention to tags you use.
You should use VARCHAR2 datatype instead of VARCHAR. Why? Oracle recommends so.
create table flight fails first as it references the airplane table, and it doesn't exist yet (at least, not in code you posted)
error you're complaining about is due to create table crewassignment. One of its foreign keys references the flight table:
FOREIGN KEY(flightdate) REFERENCES flight(flightdate)
but flight's primary key is composite, made up of 3 columns:
PRIMARY KEY(serialno,
routeno,
flightdate)
which means that you can't create that foreign key.
So, what to do? No idea, I don't know rules responsible for such a data model. Either modify primary key of the flight table, or modify foreign key constraint of the crewassingment table.
Perhaps you could add a new column to flight table (made up of a sequence (or identity column, if your database version supports it) and then let the crewassignment table reference that primary key. Columns you currently use as a primary key (serialno, routeno, flightdate) would then switch to unique key.
I use oracle and I try to have a recursive relation
CREATE TABLE "EVENT"
(
"EVENT_ID" NUMBER(18) NOT NULL, //primary key
"NAME" VARCHAR(20) NULL,
"RELATED_EVENT_ID" NUMBER(18) NULL //foreign key
);
Event 1 parent is Event 2....
When I try to create this table, I get this error.
ALTER TABLE "EVENT"
ADD CONSTRAINT "FK_RELATED_EVENT_ID"
FOREIGN KEY ("RELATED_EVENT_ID") REFERENCES "EVENT" ("RELATED_EVENT_ID")
Error report -
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
You have two problems:
There is no primary key constraint on this table.
The foreign key constraint you defined has RELATED_EVENT_ID referencing RELATED_EVENT_ID. I suspect that was just a typo.
Change your table definition to:
CREATE TABLE EVENT
(EVENT_ID NUMBER
NOT NULL
CONSTRAINT PK_EVENT
PRIMARY KEY
USING INDEX,
NAME VARCHAR2(20),
RELATED_EVENT_ID NUMBER);
Then add the foreign key constraint as
ALTER TABLE EVENT
ADD CONSTRAINT EVENT_FK1
FOREIGN KEY (RELATED_EVENT_ID) REFERENCES EVENT(EVENT_ID);
db<>fiddle here
EDIT
Note that the better way to handle this is to use a junction table, such as:
CREATE TABLE EVENT_EVENT
(EVENT_ID1 NUMBER
CONSTRAINT EVENT_EVENT_FK1
REFERENCES EVENT(EVENT_ID),
EVENT_ID2 NUMBER
CONSTRAINT EVENT_EVENT_FK2
REFERENCES EVENT(EVENT_ID),
CONSTRAINT PK_EVENT_EVENT
PRIMARY KEY (EVENT_ID1, EVENT_ID2)
USING INDEX);
Then you can drop the RELATED_EVENT_ID column from EVENT as you no longer need it.
According to oracle document :
Foreign key specifies that the values in the column must correspond to values in a
referenced primary key or unique key column or that they are NULL.
In your case, create primary key on column (EVENT_ID) and use it in reference clause as following:
ALTER TABLE "EVENT"
ADD CONSTRAINT "FK_RELATED_EVENT_ID"
FOREIGN KEY ("RELATED_EVENT_ID")
REFERENCES "EVENT" ("EVENT_ID") -- this
Now, use EVENT2's EVENT_ID as RELATED_EVENT_ID in EVENT1 record to make EVENT2 as parent of EVENT1.
Cheers!!
Maybe I'm burnout, but I don't understand this. I have two tables in Oracle: TBL_a and TBL_x. I'm trying to create a foreign key between thos two tables as follows and get error
ORA-02270: no matching unique or primary key.
CREATE TABLE tbl_a (
cod_op integer,
cod_dni char(8),
cod_correl integer,
varchar2(50)
);
CREATE TABLE tbl_x (
cod_op integer,
cod_dni char(8),
blabla varchar2(50)
);
CREATE UNIQUE INDEX TBL_A_PK ON TBL_A (COD_OP);
CREATE UNIQUE INDEX TBL_x_PK ON TBL_x (COD_OP);
ALTER TABLE TBL_a ADD CONSTRAINT TBL_a_R01
FOREIGN KEY (COD_OP) REFERENCES TBL_x (COD_OP);
The problem is that you've created unique INDEXES on your tables, but you didn't create a unique or primary key CONSTRAINT. Oracle requires that the constraints exist in order to establish a foreign key relationship.
If you drop your existing indexes and add the appropriate constraints you can establish your foreign key relationship:
DROP INDEX TBL_A_PK;
DROP INDEX TBL_x_PK;
ALTER TABLE TBL_A
ADD CONSTRAINT UQ_A
UNIQUE(COD_OP)
USING INDEX;
ALTER TABLE TBL_X
ADD CONSTRAINT UQ_X
UNIQUE(COD_OP)
USING INDEX;
dbfiddle here
The table that is referred by the foreign key (here, tbl_x) must have a primary key or a unique constraint.
In your use case, as you are declaring a unique index on cod_op, you could simply make cod_op the primary key of tbl_x instead: that would make the error disappear.
Demo on DB Fiddle
In general, it is a good practice to have a primary key on any table. Extending the principe of turning your unique indexes to primary keys, your DDL statements could be simplified as follows:
CREATE TABLE tbl_x (
cod_op INTEGER PRIMARY KEY,
cod_dni CHAR(8),
blabla VARCHAR2(50)
);
CREATE TABLE tbl_a (
cod_op INTEGER PRIMARY KEY,
cod_dni CHAR(8),
cod_correl INTEGER,
blabla VARCHAR2(50),
CONSTRAINT TBL_a_R01 FOREIGN KEY (COD_OP) REFERENCES TBL_x (COD_OP)
);
Demo on DB Fiddle
New to oracle
Im trying to assign composite key
CREATE TABLE rep_contracts
( Store_id NUMBER(8),
Name NUMBER(5)
Quarter CHAR(3),
Rep_id NUMBER(5),
CONSTRAINT rep_contracts_rep_idstore_id_pk PRIMARY KEY (rep_id, store_id),
CONSTRAINT rep_contracts_rep_id_fk FOREIGN KEY (rep_id),
CONSTRAINT rep_contracts_store_id_fk FOREIGN KEY (store_id) );
and im receiving
ORA-00972: identifier is too long
Im aware that composit key identifier longer than 30 char
but if I cut identifier few character shorter ex:
rep_contrac_rep_idstore_id_pk
then I receive
ORA-00905: missing keyword
I couldn't find any workaround
I cleaned the script and incorporated the comments:
added a comma after number(5)
changed all names to uppercase to save pain later
changed NAME which is an Oracle reserved key work to S_NAME
changed the data type from CHAR to VARCHAR2
added the references keyword to point to the table where the foreign key is
renamed the constraint so it is not more than 30 characters
like so:
CREATE TABLE rep_contracts
( STORE_ID NUMBER(8),
S_NAME NUMBER(5),
QUARTER VARCHAR2(3),
REP_ID NUMBER(5),
CONSTRAINT rep_cont_rep_idstore_id_pk PRIMARY KEY (REP_ID, STORE_ID),
CONSTRAINT rep_contracts_rep_id_fk FOREIGN KEY REFERENCES your_table(REP_ID),
CONSTRAINT rep_contracts_store_id_fk FOREIGN KEY REFERENCES your_table(STORE_ID) );