I am pretty new to SQL and I have a problem. I want to make a recursive relationship (a table that relates to itself), but I get an error when I try to execute my code. It's working fine without the Coordinator_Office_ID foreign key.
The error is:
The number of columns in the foreign-key referencing list is not equal
to the number of columns in the referenced list.
Create table Logistican (
Office_ID Number(10) Constraint nb_office Not NULL,
Worker_ID Number(15) Constraint lg_worker not null,
Name_logistican Varchar(20),
Room Varchar(10) constraint log_room UNIQUE,
Coordinator_Office_ID Integer,
Primary key (Office_ID, Worker_ID),
Constraint work_id Foreign key (Worker_ID) References worker(worker_ID) on delete cascade,
Constraint lg_cord_id Foreign key (Coordinator_Office_ID) References Logistican(Office_ID)
);
Yes, that's cause you have defined composite primary key like Primary key (Office_ID, Worker_ID) and thus your FK should include both of them else it will result in PFD (partial functional dependency)
Add the constraint with alter table:
Create table Logistican (
Office_ID Number(10) Constraint nb_office Not NULL,
Worker_ID Number(15) Constraint lg_worker not null,
Name_logistican Varchar(20),
Room Varchar(10) constraint log_room UNIQUE,
Coordinator_Office_ID Integer,
Primary key (Office_ID, Worker_ID),
Constraint work_id Foreign key (Worker_ID) References worker(worker_ID) on delete cascade
);
alter table Logistican
add Constraint lg_cord_id
Foreign key (Coordinator_Office_ID, Worker_Id) References Logistican(Office_ID, Worker_Id);
The relationship needs all elements of the primary key to be valid. I'm not sure if it needs to be a separate statement in Oracle.
Related
I'm trying to created a table, and give as a primary key, the 3 attributes, which it have.
The code is below:
CREATE TABLE compra
(
dni_cli VARCHAR2(50),
cod_prod NUMBER(10) NOT NULL,
cantidad NUMBER (10),
CONSTRAINT pk_compra PRIMARY KEY (dni_cli, cod_prod, cantidad);
CONSTRAINT pelicula_codigo_prod_fg FOREIGN KEY (cod_prod) REFERENCES producto(cod_prod),
CONSTRAINT pelicula_codigo_cli_fg FOREIGN KEY (dni_cli) REFERENCES cliente(dni)
);
I also tried to create the table first, and then, add the constraint in order to create the combined PRIMARY KEY with the alter table, but is doesn't work.
The code is this:
ALTER TABLE CONSTRAINT pk_compra PRIMARY KEY (dni_cli, cod_prod, cantidad);
If the primary key already exists you need to drop the key:
ALTER TABLE compra drop constraint pk_compra;
then add the key:
ALTER TABLE compra add constraint pk_compra primary key (city_id, buildtime, time);
If the primary key does not exist in the table then just use the second command line.
Also as #stickybit noted your table has an error. This is the code without an error:
CREATE TABLE compra (
dni_cli VARCHAR2(50),
cod_prod NUMBER(10) NOT NULL,
cantidad NUMBER (10),
CONSTRAINT pk_compra PRIMARY KEY (dni_cli,cod_prod,cantidad), --<<change here
CONSTRAINT pelicula_codigo_prod_fg FOREIGN KEY (cod_prod) REFERENCES producto(cod_prod),
CONSTRAINT pelicula_codigo_cli_fg FOREIGN KEY (dni_cli) REFERENCES cliente(dni));
I'm in the process of building a database and have already successfully created 2 primary key tables however when I try to bring them in as 2 foreign keys to another table I am running into a
"CLIENTID" invalid identifier
Unsure how to resolve as not the best at this.
CREATE TABLE Booking(
BookingID number(10) NOT NULL,
CONSTRAINT Client_FK FOREIGN KEY (ClientID) REFERENCES client (ClientID),
CONSTRAINT Course_FK FOREIGN KEY (CourseID) REFERENCES course (CourseID),
CONSTRAINT Booking_PK PRIMARY KEY (ClientID, CourseID)
);
You are missing the columns on which your primary key and foreign keys are created; you need something like the following, to be edited with the right type for your columns:
CREATE TABLE Booking(
BookingID number(10) NOT NULL,
ClientId number, -- missing
CourseID number, -- missing
CONSTRAINT Client_FK FOREIGN KEY (ClientID) REFERENCES client (ClientID),
CONSTRAINT Course_FK FOREIGN KEY (CourseID) REFERENCES course (CourseID),
CONSTRAINT Booking_PK PRIMARY KEY (ClientID, CourseID)
)
This is the table I am trying to create. However, I get the error
SQL Error: ORA-02270: no matching unique or primary key for this column-list
SQL:
create table Meets_In
(
cid char(20),
rno integer,
time char(20),
CONSTRAINT PRIM_KEY PRIMARY KEY(time),
constraint meets_fk1 foreign key(cid) references COURSES(CID),
constraint meets_fk2 foreign key(rno) references ROOMS(RNO)
);
These are the parent tables:
create table Courses
(
cid char(20),
cname char(20),
credits integer,
constraint CoursesKey Primary Key (cid, cname)
);
CREATE TABLE ROOMS
(
rno INTEGER,
address CHAR(20),
capacity INTEGER,
CONSTRAINT room_key PRIMARY KEY(rno)
);
I don't understand why I am getting this error.
Cause
The ORA-2270, as the error message suggests, happens when there is no matching unique or primary key for this column-list. This could be because
the parent lacks a constraint altogether
the parent table's constraint is a compound key and we haven't referenced all the columns in the foreign key statement.
Now in your COURSES table, CID is not a primary key. It is a combination of cid,cname. So for every cid, there can be multiple rows.
Now when you reference cid as foreign key for meets_in, it will not work as it violates the second point as I mentioned above.
Workaround
Add column cname in your meets_in table as well. Then use it like below.
create table Meets_In
(
cid char(20) not null,
cname char(20),
rno integer not null,
time1 char(20) not null,
CONSTRAINT PRIM_KEY PRIMARY KEY(time1),
constraint meets_fk1 foreign key(cid,cname) references COURSES (cid,cname), /*Added cid,cname */
constraint meets_fk2 foreign key(rno) references ROOMS (RNO)
);
Meets_In is acting as an associative table. Therefore its primary key should include the foreign keys into the tables it is associating.
Try a primary key consisting of: cid, cname, rno and time.
As others have noted, your primary key for courses is (cid, cname), so you also need to include both of these in your foreign key constraint meets_fk1. Or, if possible, ensure that cid only is the primary key on courses.
(I think time may be a reserved word, so perhaps consider renaming it.)
Im very new to SQL and i tried to create a many to many relationship:
CREATE TABLE HOUSE_USER
(
USER_ID NUMBER(10) NOT NULL,
USER_EMAIL VARCHAR(255) NOT NULL,
USER_PASSWORD VARCHAR(255) NOT NULL,
CONSTRAINT USER_PK PRIMARY KEY(USER_ID),
CONSTRAINT PROFILE_FK FOREIGN KEY(PROFILE_ID) REFERENCES HOUSE_PROFILE(PROFILE_ID)
);
CREATE TABLE HOUSE_USER_GROUPE
(
USER_GROUPE_ID NUMBER(10) NOT NULL,
USER_GROUPE_NAME VARCHAR(255) NOT NULL,
CONSTRAINT USER_GROUPE_PK PRIMARY KEY(USER_GROUPE_ID)
);
CREATE TABLE HOUSE_USER_USER_GROUPE
(
USER_ID NUMBER(10) NOT NULL,
USER_GROUPE_ID NUMBER(10) NOT NULL,
CONSTRAINT USER_USER_GROUPE_PK PRIMARY KEY(USER_ID, USER_GROUPE_ID),
CONSTRAINT USER_FK FOREIGN KEY(USER_ID) REFERENCES HOUSE_USER(USER_ID),
CONSTRAINT USER_GROUPE_FK FOREIGN KEY(USER_GROUPE_ID) REFERENCES HOUSE_USER_GROUPE(USER_GROUPE_ID)
);
I need to ask now if these two constraints:
CONSTRAINT USER_FK FOREIGN KEY(USER_ID) REFERENCES HOUSE_USER(USER_ID),
CONSTRAINT USER_GROUPE_FK FOREIGN KEY(USER_GROUPE_ID) REFERENCES
are neccessary or not. I ask because i have another many to many relationship:
CREATE TABLE HOUSE_USER_GROUPE
(
USER_GROUPE_ID NUMBER(10) NOT NULL,
USER_GROUPE_NAME VARCHAR(255) NOT NULL,
CONSTRAINT USER_GROUPE_PK PRIMARY KEY(USER_GROUPE_ID)
);
CREATE TABLE HOUSE_ACCESSR
(
ACCESSR_ID NUMBER(10) NOT NULL,
ACCESSR_NAME VARCHAR(255) NOT NULL,
CONSTRAINT ACCESSR_PK PRIMARY KEY(ACCESSR_ID)
);
CREATE TABLE HOUSE_USER_GROUPE_ACCESR
(
USER_GROUPE_ID NUMBER(10) NOT NULL,
ACCESSR_ID NUMBER(10) NOT NULL,
CONSTRAINT USER_GROUPE_ACCESSR_PK PRIMARY KEY(USER_GROUPE_ID, ACCESSR_ID),
CONSTRAINT USER_GROUPE_FK FOREIGN KEY(USER_GROUPE_ID) REFERENCES HOUSE_USER_GROUPE(USER_GROUPE_ID),
CONSTRAINT ACCESSR_FK FOREIGN KEY(ACCESSR_ID) REFERENCES HOUSE_ACCESSR(ACCESSR_ID)
);
I cant create the second many to many table because i already used the constraint:
CONSTRAINT USER_GROUPE_FK FOREIGN KEY(USER_GROUPE_ID) REFERENCES HOUSE_USER_GROUPE(USER_GROUPE_ID),
I could just rename it but because of that error:
ORA-02264: name already used by an existing constraint
I just was wondering if these constraints are mandatory.
Yes, you should create the foreign key constrain on both tables.
The foreign key constraints are there to maintain referential integrity; ensuring that you can't insert values that don't exist in the parent table.
If you don't add the constraint to HOUSE_USER_GROUPE_ACCESR then you don't get that protection in that table. And you should want that protection everywhere.
Your only apparent mistake is that the constraint names are identical to each other. I traditionally either include No Name (letting Oracle decide on the name, because I never refer to the constraint by name) or use a format something like fk_<table>_<field>.
You need to do the constraints.. create the second constraints with another name.
Unable to create table as oracle shows ' no matching unique or primary key for this column-list' when I did label the primary key reference for the required table.
First table created successfully:
CREATE TABLE TEST
(
TESTno VARCHAR2(6) NOT NULL,
ExamNo VARCHAR2(6) NOT NULL,
TEST_Date DATE NOT NULL,
ACTUAL DATE,
PREDICTED Date,
CONSTRAINT TESTPKs PRIMARY KEY (TEST_Date, TESTno, ExamNo),
CONSTRAINT TTESTNO_Fk FOREIGN KEY (TESTno) REFERENCES TESTPAPER (Flightno)
CONSTRAINT TEXAMNo_FK FOREIGN KEY (ExamNo) REFERENCES Exam (ExamNo)
);
Here's the table i want to create and gives me error:
CREATE TABLE Assignment
(
TEST_Date DATE NOT NULL,
ExamNo VARCHAR2(6) NOT NULL,
TestNo VARCHAR2(6) NOT NULL,
Type VARCHAR2(20),
Hours_Spent Decimal(4,2),
CONSTRAINT ASSIGNPKS PRIMARY KEY (TEST_Date, TestNo , ExamNo),
CONSTRAINT ASSIGNTESTDATE_FK FOREIGN KEY (TEST_Date) REFERENCES TEST(TEST_Date) ON
DELETE CASCADE,
CONSTRAINT ASSIGNTESTNO_FK FOREIGN KEY (TESTno) REFERENCES TESTPAPER (Flightno)
CONSTRAINT TEXAMNo_FK FOREIGN KEY (ExamNo) REFERENCES Exam (ExamNo)
);
May i know where's the issue that it keeps giving me no matching unique primary keys? I already tried to recreate and labelled the 'test_Date' as my primary key. But oracle can't seems to find.
Thanks
The PK you refer to is PRIMARY KEY (TEST_Date, TESTno, ExamNo) — hence the foreign key should be FOREIGN KEY (TEST_Date, TESTno, ExamNo) as well. The error you're getting is due to your attempt to refer to a part of TEST's PK.
See also http://download.oracle.com/docs/cd/B10500_01/server.920/a96524/c22integ.htm
Check the tables you are referencing in your foreign keys. Those columns must be the primary key or otherwise unique on the foreign table.